Re: PDP 11 gear finally moved

[Local52Mixer]

Hi all,
 
Question to the group...not a vintage computer problem.  A problem  with a 
much newer system.  An Acer Aspire desktop about 10 years old.   I'm trying 
to sell it and reset windows (vista) to factory original.  It  locked up'd 
during that process and I reset it.  Seems the BIOS is now  corrupted.  I 
need to re-flash the BIOS and to do that I need a bootable CD  disk.
 
I have tried several times to format a brand new disk and make it a boot  
disk.  Problem is the format option under Windows 8 doesn't allow me to  
click that make boot disk option.  Any ideas on how to create a boot  disk for 
a 
windows vista system?  Once I have the boot disk, it's a simple  matter to 
copy the BIOS files to that disk and re-flash the system.   Once it is 
started again, I can see what's up with the original Vista or whether  i need 
to 
do a full re-load.
 
I would like any ideas anyone has to offer.  I have lots of computer  gear 
and need to "cull the heard", too much space and I'm moving soon.  I  hate 
to see a buyer slip away.
 
You can email me directly at _local52mixer@aol.com_ 
(mailto:local52mi...@aol.com)  _or_ (mailto:local52mixer@or)  call my 
cell...732-530-1924.
 
Thanks in advance,
BD
 
 
In a message dated 7/24/2015 1:18:09 A.M. Eastern Daylight Time,  
tothw...@concentric.net writes:

On Wed,  22 Jul 2015, Chuck Guzis wrote:
> On 07/22/2015 10:09 PM, Tothwolf  wrote:
>
>> One example I can give are some Pentium P55C  architecture (Socket 7) 
>> systems which I've been running with  minimal downtime for ~15 years. 
>> The original power supplies with  their original (and relatively low 
>> quality) capacitors lasted  about 15 to 17 years (I think the 
>> manufacture date code stamped  on the oldest one was 1998) before the 
>> systems began to develop  stability issues, requiring me to rebuild the 
>> power supplies with  new capacitors. I fully expect that the 
>> replacements would last  even longer than 20 years, however I rather 
>> doubt I'll be running  those computers by then.
>
> Does anyone have much experience with  the so-called "solid electrolyte" 
> electrolytics?  Fvor replacing  vintage caps, they're probably not a 
> viable choice as they're mostly  SMT, but just wondering...

I believe there are a few webpages out there  written by people who have 
tried it. From what I remember reading about  them years ago, they had no 
success when they tried to use them as  replacements in switch mode power 
supplies (no surprise, since the solid  polymer parts they attempted to use 
had way to low of ripple current  rating for that application) but had 
better results with certain PC  motherboards.

I use solid polymers as replacements in some  applications, and as they 
continue to decrease in cost, I've been  considering using them more for 
replacement of aging SMD aluminum  electrolytics. One application where I 
particularly like solid polymers is  for replacement of the vcore regulator 
filter capacitors on Pentium 4  industrial single board computers (yes, the 
P4 is still /widely/ used and  extremely common in that market, although it 
is slowly being replaced by  the Core Duo). The original aluminum 
electrolytics in that application are  usually 6.3V rated parts while the 
solid polymer replacements are 2.5V or  4V (vcore is under 2V).

In addition to long term stability, another  major benefit to solid 
polymers is that unlike aluminum electrolytics and  solid tantalums, solid 
aluminum polymers they can be used at their full  rated voltage with no ill 
effects. The only real downside that I know of  for a solid polymer is that 
they have an incredibly low ESR (less than  0.01 ohm), which can actually 
upset older circuit designs which were not  designed for capacitors with 
such a low  ESR.

Re: Dumping Intel 43201 microcode ROM

[Andrew Jones]

Eric, a friend pointed me to your inspiring ClassicCMP post about 
getting your 432 online.  The photos of your home-made QUIP socket were 
really cool.


I reached out today because I've been wanting to hack on a 432 emulator 
for some years, ever since I found some contemporary textbooks about the 
architecture.  Unfortunately, object code in good condition is very hard 
to find.


I've been working on some floppy images, but they were taken using a 
non-MDS floppy drive from very poor quality media.  Progress is slow.


I was wondering if I could have a copy of your microcode dump.  I 
realize, being microcode, it is not object code in the most meaningful 
sense of the word, but it's a lot more than I've been able to locate so far.

First Computer Store

[Murray McCullough]

A momentus event happened 40 years ago around this time, July 1975,
the world's first computer store opened in West Los Angeles, called
Arrow Head Computer Store, tag-lined, 'The Computer Store'. It was
opened by Dick Heiser. How time has flown by!

Murray  :)

Re: Chromatics on ebay

[Sean Caron]

+1; weak sauce from the seller ... he listed it and the auction ran to
completion ... It always irks me when people renege on eBay auctions.

Best,

Sean


On Thu, Jul 23, 2015 at 5:12 PM, Todd Goodman  wrote:

> That's just seller's remorse.
>
> It's obviously up to you, but I'd have strongly considered disputing it
> with
> eBay as a seller refusing to honor the auction results is every bit as
> bad (or even worse) than a buyer refusing to honor the auction result.
>
> The value of it was determined.  It's the $5 you were willing to pay and
> that no one else was willing to pay more for it.
>
> Just my worthless $.02
>
> Todd
>
> * Josh Dersch  [150723 17:03]:
> > Just FYI -- the seller and I failed to reach an agreement; I assume this
> > means he'll be relisting it (hopefully with a starting bid or reserve
> that
> > matches his expectations).
> >
> > - Josh
> >
> > On Thu, Jul 23, 2015 at 10:45 AM, william degnan 
> > wrote:
> >
> > > I told him he might get $500 in untested condition, a lot more if it
> > > works.  Video, good pics, be ready with a ship quote, etc.   He may
> have
> > > asked more than just me, but that is what I told him
> > > On Jul 23, 2015 12:31 PM, "Josh Dersch"  wrote:
> > >
> > > > It was me.  Despite the listing being "local pickup only" the
> description
> > > > notes that the seller's willing to arrange shipping (it just won't be
> > > > cheap).  So I put in a lowball bid on it.  Did not expect to be the
> high
> > > > bidder, definitely did not expect to be the only bidder.
> > > >
> > > > That said, immediately after the auction ended, the seller contacted
> me
> > > > and explained that he'd screwed up; he's new to eBay, couldn't
> figure out
> > > > how to set a reserve (or an opening bid amount, apparently) and just
> > > > couldn't let the thing go for $5.  Since I'm not completely heartless
> > > (just
> > > > mostly) I'm trying to work something out with him, but we'll see; he
> > > seems
> > > > to think it's worth a fortune -- I'm not so sure.  (Rare doesn't
> > > > necessarily equate to worth and all that...)
> > > >
> > > > If I do end up with the system, I'll dump the ROMs, etc.
> > > >
> > > > - Josh
> > > >
> > > >
> > > > On 7/23/15 7:24 AM, Al Kossow wrote:
> > > >
> > > >> did anyone here get this?
> > > >>
> > > >> http://www.ebay.com/itm/281752359535
> > > >>
> > > >> I am interested in a firmware dump, but not enough to drive to
> socal to
> > > >> get it.
> > > >>
> > > >>
> > > >>
> > > >
> > >
>

Re: Chromatics on ebay

[Tothwolf]

On Thu, 23 Jul 2015, William Donzelli wrote:


That's just seller's remorse.

It's obviously up to you, but I'd have strongly considered disputing it 
with eBay as a seller refusing to honor the auction results is every 
bit as bad (or even worse) than a buyer refusing to honor the auction 
result.


I agree. Report him.

Basic Ebay auctions are extremely easy to do - any idiot can do it.

He had six days while he could review and make sure everything was OK, 
and revise the listing if and error was spotted.


Within the last year or so, eBay removed the ability to report a 
"non-selling seller". The only way to report a seller for this now (so 
they get a "strike" on their account) is to pick up the phone and call 
eBay. You have to ask (demand) to speak to someone in "Trust and Safety" 
and you also have to be prepared to spend about an hour or so on hold.

Re: PDP 11 gear finally moved

[Tothwolf]

On Wed, 22 Jul 2015, Chuck Guzis wrote:

On 07/22/2015 10:09 PM, Tothwolf wrote:

One example I can give are some Pentium P55C architecture (Socket 7) 
systems which I've been running with minimal downtime for ~15 years. 
The original power supplies with their original (and relatively low 
quality) capacitors lasted about 15 to 17 years (I think the 
manufacture date code stamped on the oldest one was 1998) before the 
systems began to develop stability issues, requiring me to rebuild the 
power supplies with new capacitors. I fully expect that the 
replacements would last even longer than 20 years, however I rather 
doubt I'll be running those computers by then.


Does anyone have much experience with the so-called "solid electrolyte" 
electrolytics?  Fvor replacing vintage caps, they're probably not a 
viable choice as they're mostly SMT, but just wondering...


I believe there are a few webpages out there written by people who have 
tried it. From what I remember reading about them years ago, they had no 
success when they tried to use them as replacements in switch mode power 
supplies (no surprise, since the solid polymer parts they attempted to use 
had way to low of ripple current rating for that application) but had 
better results with certain PC motherboards.


I use solid polymers as replacements in some applications, and as they 
continue to decrease in cost, I've been considering using them more for 
replacement of aging SMD aluminum electrolytics. One application where I 
particularly like solid polymers is for replacement of the vcore regulator 
filter capacitors on Pentium 4 industrial single board computers (yes, the 
P4 is still /widely/ used and extremely common in that market, although it 
is slowly being replaced by the Core Duo). The original aluminum 
electrolytics in that application are usually 6.3V rated parts while the 
solid polymer replacements are 2.5V or 4V (vcore is under 2V).


In addition to long term stability, another major benefit to solid 
polymers is that unlike aluminum electrolytics and solid tantalums, solid 
aluminum polymers they can be used at their full rated voltage with no ill 
effects. The only real downside that I know of for a solid polymer is that 
they have an incredibly low ESR (less than 0.01 ohm), which can actually 
upset older circuit designs which were not designed for capacitors with 
such a low ESR.

Re: Chromatics on ebay

[Noel Chiappa]

> From: Josh Dersch

> I spent some time debating that last night and this morning. Chalk it
> up to me feeling charitable this week ... I thought I'd give the guy a
> break.

Well, the question is, how important is this gear to you? If you've been
looking for one for a decade, that's different from if you just saw it and
said 'that looks cool'. If the latter, yeah, you can be quite charitable.

Which would mean, e.g. that you could agree to pass on enforcing the contract
if the seller agrees to immediately re-list the item in another open auction,
with a minimum reasonable reserve (I'd say $50, myself), and absolute
commitment to go through with the sale, no matter what. After all, an open
auction _is_ the current _real value_ for something.

And they should understand that if they persist in selecting 'local pickup
only', the value of the piece drops by about 75% - or more - it's cutting the
size of the pool of bidders by like 95% (LA area population / total US
population) by doing so.

Noel

Re: Fwd: Old gear avail in NY

[Steven M Jones]

On 07/23/2015 18:18, Tapley, Mark wrote:

forwarded from Cindy at Electronics Plus. Contact eaustin in NY directly

[...]

Please email eaus...@sunnking.com if you are 
interested in purchasing these or similar items in quantity.


Sounds suspiciously like it might be prolific, long-time eBay seller 
"sunnking":


http://www.ebay.com/usr/sunnking?_trksid=p2047675.l2559

They have old PCs and components currently listed. Wonder what's 
prompted the urge to purge...

--S.

Re: VCF Midwest 10

[Jason T]

A few notes regarding the upcoming 10th incarnation of the Midwest's
finest retro technology/hacker/pizza con:

- The dates are August 29th and 30th, with early load-in and dinner on
the night of the 28th.  Can't mention that enough.

- Table registration has closed (Check out our exhibitor list at
http://vcfmw.org/ex.html)!  We have however rented an extra room which
will be used for "overflow" and late-comers.  Unlike the main hall, it
will not be assigned spaces.  If you'd like to show or sell, come
early and grab what space is left.

- There is - I've been told - a free shuttle from O'Hare airport
(KORD) to the hotel.  Look for the Holiday Inn bus where the hotel
transport congregates.  Could be the tipping point that brings in one
or two more out-of-towners!

- If you are making the trip and have not yet made your hotel
reservation, please do so now!  Our pre-arranged block (linked at
vcfmw.org) closes on the 31st.  As of this Monday, there were seven
block-rate rooms remaining.

- There is still room on the schedule for speakers
(http://vcfmw.org/pres.html).  If enjoy addressing groups of nerds and
can put together 30 or so minutes on a relevant topic, please let me
know.

- Seriously, look at this stuff:  http://loumalnatis.com.  People come
to Chicago just to eat there.  You can do that and hang out with us.


I want to say THANK YOU to everyone who is coming out - from near or
far - and making the show what it is.  It's your demos, expertise,
unique stories and experiences and clever projects that make it all
worthwhile.  Without you, we'd be a few guys hanging out for an
afternoon in a hotel and talking about old computers before going out
for pizza.  But thanks to you, we're over 100 people, and we spend a
whole weekend on it.

See you in August,

-j

Re: diagnosing an Intel Series II MDS monitor failure

[Eric Smith]

Al wrote:
> does it have a horizontal oscillator?
> some ball monitors require horizonal drive before the hv works

It doesn't appear to have a horizontal oscillator.

Re: diagnosing an Intel Series II MDS monitor failure

[Al Kossow]

On 7/23/15 6:56 PM, Eric Smith wrote:

I'll test the
monitor on a lab power supply to see if it's drawing too much current.


does it have a horizontal oscillator?

some ball monitors require horizonal drive before the hv works

diagnosing an Intel Series II MDS monitor failure

[Eric Smith]

A few weeks ago, while I was testing a spare IPB-80 CPU card in an
Intel Series II MDS, the monitor stopped working, with the raster
collapsing to a very bright dot in the center of the screen. I hit the
power switch and pulled the line plug immediately, but the dot
persisted for several minutes, only gradually dimming.

I just started investigating it. With the monitor cable unplugged from
the IOC board, the +15V DC at the IOC connector reads 0.74V. Of the
two DC power supplies described in the service manual, this MDS uses
the Power One. The +15V rail uses a separate transformer winding, a
723C regulator, a house-marked (12500-4) NPN pass transistor, and a
zener and SCR crowbar. The 0.74V makes me think the crowbar has
tripped and the 723 regulator is current limiting. Nothing else in the
MDS uses the +15V supply.

I was a bit lucky that this particular MDS used "method A" of
installing the monitor, which makes it easier to remove. Once the
metal shield is removed, the label was visible. It is a Ball
Electronic Displays TV-120 monitor, which is a common enough model
that it was easy to find the service manual online. I'll test the
monitor on a lab power supply to see if it's drawing too much current.
I may kludge up Rich Ottosen's PIC-based TV test pattern generator on
a breadboard.

Re: Chromatics on ebay

[William Donzelli]

> I'm also trying to be a nicer person (look how few arguments I've gotten in
> on cctalk lately!  progress!) and I thought I'd give the guy a break.  But
> I'm still pretty ticked off about it, so maybe I'll reconsider :).

Reconsider with some shitty feedback.

--
Will

Re: Chromatics on ebay

[Josh Dersch]

On Thu, Jul 23, 2015 at 2:15 PM, William Donzelli 
wrote:

> > That's just seller's remorse.
> >
> > It's obviously up to you, but I'd have strongly considered disputing it
> with
> > eBay as a seller refusing to honor the auction results is every bit as
> > bad (or even worse) than a buyer refusing to honor the auction result.
>
> I agree. Report him.
>
> Basic Ebay auctions are extremely easy to do - any idiot can do it.
>
> He had six days while he could review and make sure everything was OK,
> and revise the listing if and error was spotted.
>


Yeah, I spent some time debating that last night and this morning.  Chalk
it up to me feeling charitable this week, but I felt like giving him the
benefit of the doubt on the situation, and having been there in the past
with eBay sales that don't go the way I want them to, I'm a bit empathetic
(though I didn't try to back out of the sale in those cases...).

I'm also trying to be a nicer person (look how few arguments I've gotten in
on cctalk lately!  progress!) and I thought I'd give the guy a break.  But
I'm still pretty ticked off about it, so maybe I'll reconsider :).

- Josh



>
> --
> Will
>

Fwd: Old gear avail in NY

[Tapley, Mark]

All,
forwarded from Cindy at Electronics Plus. Contact eaustin in NY directly if you 
are interested. No connection, just forwarding.
- Mark

Begin forwarded message:

From: mailto:sa...@elecplus.com>>
Subject: Old gear avail in NY
Date: July 22, 2015 at 12:49:02 PM CDT
To: Mark Tapley mailto:mtap...@swri.edu>>

I still can't post to the list!

We are looking for wholesale buyers of legacy (early 90’s) PC parts & 
accessories:

IBM, Tandy, Amiga, Packard Bell, Gateway 2000, etc
Motherboards
Sound Cards - Creative Sound Blaster
Display / Video cards
Hard Drives – Seagate, Conner, WD, IBM <2GB
Keyboards
& more

Items can be tested before sale if necessary.
Please email eaus...@sunnking.com if you are 
interested in purchasing these or similar items in quantity. Thanks!

He is in NY.

Cindy

Re: Chromatics on ebay

[Jason T]

Another thing that will affect the value here that I don't think has
been pointed out yet: the seller apparently has three of these things
(note his responses to bidder questions.)

And another another thing:  they've also been sitting outside for who
knows how many years.

Re: Chromatics on ebay

[william degnan]

obviously not in this case!
On Jul 23, 2015 8:21 PM, "Ian Finder"  wrote:

> Just for the record, I hate the methodology below:
> Are auctions no longer a valid way to determine value?
>
>
> > I told him start with buy it now for $2000 with best offer, leave it
> > to see what kind of watchers and interest he gets then lower the price
> > until a sale is made.
>
> Sent from my iPhone
>
> > On Jul 23, 2015, at 15:08, william degnan  wrote:
>
> > I told him start with buy it now for $2000 with best offer, leave it
> > to see what kind of watchers and interest he gets then lower the price
> > until a sale is made.
>
> >  That said, because you're asking for the item
> > to be shipped, the seller can refuse on that ground,  you have a
> > Mexican standoff.  I believe it's ok to say Mexican standoff because
> > that's a historic not racial reference, having to do with 19th century
> > Mexican history.
> >
> > On Thu, Jul 23, 2015 at 5:27 PM, Noel Chiappa 
> wrote:
> >>> From: Josh Dersch
> >>
> >>> the seller and I failed to reach an agreement
> >>
> >> You were very nice to try and work with the person; if they couldn't
> take that
> >> on board, and in return come to some agreement that you could be happy
> with,
> >> they're being some combinations of greedy and unreasonable.
> >>
> >> I have to agree with other people: an open auction was held, and the
> value of
> >> the item was determined by that to be $5. End of story.
> >>
> >>Noel
> >
> >
> >
> > --
> > Bill
> > vintagecomputer.net
>

Re: Chromatics on ebay

[Ian Finder]

Just for the record, I hate the methodology below:
Are auctions no longer a valid way to determine value?


> I told him start with buy it now for $2000 with best offer, leave it
> to see what kind of watchers and interest he gets then lower the price
> until a sale is made. 

Sent from my iPhone

> On Jul 23, 2015, at 15:08, william degnan  wrote:

> I told him start with buy it now for $2000 with best offer, leave it
> to see what kind of watchers and interest he gets then lower the price
> until a sale is made. 

>  That said, because you're asking for the item
> to be shipped, the seller can refuse on that ground,  you have a
> Mexican standoff.  I believe it's ok to say Mexican standoff because
> that's a historic not racial reference, having to do with 19th century
> Mexican history.
> 
> On Thu, Jul 23, 2015 at 5:27 PM, Noel Chiappa  
> wrote:
>>> From: Josh Dersch
>> 
>>> the seller and I failed to reach an agreement
>> 
>> You were very nice to try and work with the person; if they couldn't take 
>> that
>> on board, and in return come to some agreement that you could be happy with,
>> they're being some combinations of greedy and unreasonable.
>> 
>> I have to agree with other people: an open auction was held, and the value of
>> the item was determined by that to be $5. End of story.
>> 
>>Noel
> 
> 
> 
> -- 
> Bill
> vintagecomputer.net

Re: Chromatics on ebay

[John Robertson]

On 07/23/2015 2:15 PM, William Donzelli wrote:

That's just seller's remorse.

It's obviously up to you, but I'd have strongly considered disputing it with
eBay as a seller refusing to honor the auction results is every bit as
bad (or even worse) than a buyer refusing to honor the auction result.

I agree. Report him.

Basic Ebay auctions are extremely easy to do - any idiot can do it.

He had six days while he could review and make sure everything was OK,
and revise the listing if and error was spotted.

--
Will

I had a buyers remorse back in 2006 where a very rare (only one or two 
on the planet) vintage arcade game we were selling got something like 
$4000 at the close. The buyer (call him B/R) pleaded with me to cancel 
his bid as he said he accidentally typed the wrong amount in.


I agreed to cancel the auction.

The item ended up selling for around $750 to the person who was the 
other bidder (call him O/B) who had bid it up to around $3995. However 
O/B has since spent a fair bit of money at my shop and both participants 
are nice guys.


What was interesting is the buyer (B/R) who backed out, had a garage 
storage unit that he had forgotten about and the owner of the garage 
contacted me after not hearing from B/R for many months sold me the 
classic games at a very good price.


I ended up doing just fine as a result.

My 2 cents.

John :-#)#

Re: Chromatics on ebay

[wulfman]

You can offer to take him to small claims court for the item. That
option has worked well for me in the past.
Once you let them know the option of a court case is real they are more
than willing to deal with the contract.
IT's quite clear in the ebay auction terms.



On 7/23/2015 3:54 PM, Noel Chiappa wrote:
> > From: william degnan
>
> > I told him start with buy it now for $2000 with best offer
>
> And there's the key to the situation. The seller thought they were going to
> get big dineros for it, and not so much.
>
> Which is likely a good part of why they aren't being reasonable in the
> post-sale negotiations with Josh.
>
>
> > because you're asking for the item to be shipped, the seller can refuse
> > on that ground
>
> Err, the listing does say:
>
>   "I dont wanna have to mess with shipping, but if you absolutely need it
>   shipped we can work something out."
>
> So I don't think that dog will hunt.
>
> But, just to close that door, is there anyone in the LA area who can, in
> fact, go pick this thing up, and ship it off to Josh? That would leave the
> seller without a leg.
>
>
> But the seller does only have a feedback of 4, so maybe they really are
> clueless about eBay.
>
> But the bottom line is that the _reality_ is that honouring the contract with
> Josh is _not_ going to cost the seller a lot of money - because in an _open
> auction_, it went for $5.
>
>   Noel
>


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Re: Chromatics on ebay

[Noel Chiappa]

> From: william degnan

> I told him start with buy it now for $2000 with best offer

And there's the key to the situation. The seller thought they were going to
get big dineros for it, and not so much.

Which is likely a good part of why they aren't being reasonable in the
post-sale negotiations with Josh.


> because you're asking for the item to be shipped, the seller can refuse
> on that ground

Err, the listing does say:

  "I dont wanna have to mess with shipping, but if you absolutely need it
  shipped we can work something out."

So I don't think that dog will hunt.

But, just to close that door, is there anyone in the LA area who can, in
fact, go pick this thing up, and ship it off to Josh? That would leave the
seller without a leg.


But the seller does only have a feedback of 4, so maybe they really are
clueless about eBay.

But the bottom line is that the _reality_ is that honouring the contract with
Josh is _not_ going to cost the seller a lot of money - because in an _open
auction_, it went for $5.

Noel

Re: Chromatics on ebay

[Chuck Guzis]

On 07/23/2015 03:27 PM, William Donzelli wrote:

It is always hard to know the real story. It *is* possible the seller
genuinely didn't know what they were doing.


As an Ebay veteran, I can say I have heard ALL the excuses. This does
sound like classic sellers remorse.


I agree with this.  I've seen cases where someone cleaned out a basement 
and turned up a really valuable musical instrument, put it up for 
auction, then refused to honor the hammer price.  It also happens that 
the seller will sometimes claim that the item was stolen or damaged or 
even lost in shipping to get out of the deal.  Often, someone will 
contact the seller and make a private offer.  Then, suddenly, the item 
becomes "not available".  I thought that one of the eBay rules was that 
a seller can cancel the auction only before a qualified bid (i.e. one 
that meets the reserve, if any) has been received.


Didn't eBay used to (perhaps still does) say that "Your bid is a 
contract".  Well, contracts can't be one-sided.


--Chuck

Re: Chromatics on ebay

[William Donzelli]

> It is always hard to know the real story. It *is* possible the seller
> genuinely didn't know what they were doing.

As an Ebay veteran, I can say I have heard ALL the excuses. This does
sound like classic sellers remorse.

If he really though it was worth serious money, he should have been
more careful, and figured out AND REVIEWED his actions placing the
thing on Ebay.

--
Will

Re: Chromatics on ebay

[william degnan]

different than chromatix, correct?

On Thu, Jul 23, 2015 at 6:12 PM, Jarratt RMA
 wrote:
> It is always hard to know the real story. It *is* possible the seller
> genuinely didn't know what they were doing. I know I can be too willing to
> give others the benefit of the doubt, and, equally this could be an
> experienced seller pretending not to know, when his plan to avoid higher
> insertion fees failed. I would be inclined to report him if he wasn't
> prepared to accept an offer that was (presumably) more generous than the
> final bid.
>
> Regards
>
> Rob
>
> On 23 July 2015 at 22:27, Noel Chiappa  wrote:
>
>> > From: Josh Dersch
>>
>> > the seller and I failed to reach an agreement
>>
>> You were very nice to try and work with the person; if they couldn't take
>> that
>> on board, and in return come to some agreement that you could be happy
>> with,
>> they're being some combinations of greedy and unreasonable.
>>
>> I have to agree with other people: an open auction was held, and the value
>> of
>> the item was determined by that to be $5. End of story.
>>
>> Noel
>>



-- 
Bill
vintagecomputer.net

Re: Chromatics on ebay

[Jarratt RMA]

It is always hard to know the real story. It *is* possible the seller
genuinely didn't know what they were doing. I know I can be too willing to
give others the benefit of the doubt, and, equally this could be an
experienced seller pretending not to know, when his plan to avoid higher
insertion fees failed. I would be inclined to report him if he wasn't
prepared to accept an offer that was (presumably) more generous than the
final bid.

Regards

Rob

On 23 July 2015 at 22:27, Noel Chiappa  wrote:

> > From: Josh Dersch
>
> > the seller and I failed to reach an agreement
>
> You were very nice to try and work with the person; if they couldn't take
> that
> on board, and in return come to some agreement that you could be happy
> with,
> they're being some combinations of greedy and unreasonable.
>
> I have to agree with other people: an open auction was held, and the value
> of
> the item was determined by that to be $5. End of story.
>
> Noel
>

Re: Chromatics on ebay

[william degnan]

I told him start with buy it now for $2000 with best offer, leave it
to see what kind of watchers and interest he gets then lower the price
until a sale is made.  That said, because you're asking for the item
to be shipped, the seller can refuse on that ground,  you have a
Mexican standoff.  I believe it's ok to say Mexican standoff because
that's a historic not racial reference, having to do with 19th century
Mexican history.

On Thu, Jul 23, 2015 at 5:27 PM, Noel Chiappa  wrote:
> > From: Josh Dersch
>
> > the seller and I failed to reach an agreement
>
> You were very nice to try and work with the person; if they couldn't take that
> on board, and in return come to some agreement that you could be happy with,
> they're being some combinations of greedy and unreasonable.
>
> I have to agree with other people: an open auction was held, and the value of
> the item was determined by that to be $5. End of story.
>
> Noel



-- 
Bill
vintagecomputer.net

Re: Chromatics on ebay

[Noel Chiappa]

> From: Josh Dersch

> the seller and I failed to reach an agreement

You were very nice to try and work with the person; if they couldn't take that
on board, and in return come to some agreement that you could be happy with,
they're being some combinations of greedy and unreasonable.

I have to agree with other people: an open auction was held, and the value of
the item was determined by that to be $5. End of story.

Noel

Re: PDP 11 gear finally moved

[Eric Smith]

I wrote:
>> I proposed it, and was willing to build microcontroller-based boards
>> and write firmware, but IIRC it was decided that there was too little
>> benefit.

On Thu, Jul 23, 2015 at 12:00 PM, William Donzelli  wrote:
> That seems odd, considering the lengths you guys took on the caps, and
> the whole museum mentality of keeping things "safe" for the artifacts.

There's no artifact safety issue for the PDP-1 power supplies.  They
use a ferroresonant transformer, rectifiers, and filter capacitors.
If any of those fail, the machine won't work properly, but it won't be
damaged.

If there had been voltage regulators, the failure of which could have
resulted in serious overvoltage, we probably would have added crowbar
circuits.

In the Type 30 display, it's possible, though rather unlikely, for a
failure in the deflection power supply to blow the deflection drive
transistors. Adding a microcontroller isn't likely to avoid that. A
crowbar circuit might be useful, though the damage happens so quickly
that the deflection transistors might still fail.

Re: Chromatics on ebay

[William Donzelli]

> That's just seller's remorse.
>
> It's obviously up to you, but I'd have strongly considered disputing it with
> eBay as a seller refusing to honor the auction results is every bit as
> bad (or even worse) than a buyer refusing to honor the auction result.

I agree. Report him.

Basic Ebay auctions are extremely easy to do - any idiot can do it.

He had six days while he could review and make sure everything was OK,
and revise the listing if and error was spotted.

--
Will

Re: Chromatics on ebay

[Todd Goodman]

That's just seller's remorse.

It's obviously up to you, but I'd have strongly considered disputing it with
eBay as a seller refusing to honor the auction results is every bit as
bad (or even worse) than a buyer refusing to honor the auction result.

The value of it was determined.  It's the $5 you were willing to pay and
that no one else was willing to pay more for it.

Just my worthless $.02

Todd

* Josh Dersch  [150723 17:03]:
> Just FYI -- the seller and I failed to reach an agreement; I assume this
> means he'll be relisting it (hopefully with a starting bid or reserve that
> matches his expectations).
> 
> - Josh
> 
> On Thu, Jul 23, 2015 at 10:45 AM, william degnan 
> wrote:
> 
> > I told him he might get $500 in untested condition, a lot more if it
> > works.  Video, good pics, be ready with a ship quote, etc.   He may have
> > asked more than just me, but that is what I told him
> > On Jul 23, 2015 12:31 PM, "Josh Dersch"  wrote:
> >
> > > It was me.  Despite the listing being "local pickup only" the description
> > > notes that the seller's willing to arrange shipping (it just won't be
> > > cheap).  So I put in a lowball bid on it.  Did not expect to be the high
> > > bidder, definitely did not expect to be the only bidder.
> > >
> > > That said, immediately after the auction ended, the seller contacted me
> > > and explained that he'd screwed up; he's new to eBay, couldn't figure out
> > > how to set a reserve (or an opening bid amount, apparently) and just
> > > couldn't let the thing go for $5.  Since I'm not completely heartless
> > (just
> > > mostly) I'm trying to work something out with him, but we'll see; he
> > seems
> > > to think it's worth a fortune -- I'm not so sure.  (Rare doesn't
> > > necessarily equate to worth and all that...)
> > >
> > > If I do end up with the system, I'll dump the ROMs, etc.
> > >
> > > - Josh
> > >
> > >
> > > On 7/23/15 7:24 AM, Al Kossow wrote:
> > >
> > >> did anyone here get this?
> > >>
> > >> http://www.ebay.com/itm/281752359535
> > >>
> > >> I am interested in a firmware dump, but not enough to drive to socal to
> > >> get it.
> > >>
> > >>
> > >>
> > >
> >

Re: Chromatics on ebay

[Josh Dersch]

Just FYI -- the seller and I failed to reach an agreement; I assume this
means he'll be relisting it (hopefully with a starting bid or reserve that
matches his expectations).

- Josh

On Thu, Jul 23, 2015 at 10:45 AM, william degnan 
wrote:

> I told him he might get $500 in untested condition, a lot more if it
> works.  Video, good pics, be ready with a ship quote, etc.   He may have
> asked more than just me, but that is what I told him
> On Jul 23, 2015 12:31 PM, "Josh Dersch"  wrote:
>
> > It was me.  Despite the listing being "local pickup only" the description
> > notes that the seller's willing to arrange shipping (it just won't be
> > cheap).  So I put in a lowball bid on it.  Did not expect to be the high
> > bidder, definitely did not expect to be the only bidder.
> >
> > That said, immediately after the auction ended, the seller contacted me
> > and explained that he'd screwed up; he's new to eBay, couldn't figure out
> > how to set a reserve (or an opening bid amount, apparently) and just
> > couldn't let the thing go for $5.  Since I'm not completely heartless
> (just
> > mostly) I'm trying to work something out with him, but we'll see; he
> seems
> > to think it's worth a fortune -- I'm not so sure.  (Rare doesn't
> > necessarily equate to worth and all that...)
> >
> > If I do end up with the system, I'll dump the ROMs, etc.
> >
> > - Josh
> >
> >
> > On 7/23/15 7:24 AM, Al Kossow wrote:
> >
> >> did anyone here get this?
> >>
> >> http://www.ebay.com/itm/281752359535
> >>
> >> I am interested in a firmware dump, but not enough to drive to socal to
> >> get it.
> >>
> >>
> >>
> >
>

paging Paul Birkel

[Jay West]

List - sorry for the noise..

 

Paul - sent you a couple emails on the 2100 front, wasn't sure if you got
them (re: WCS boards).

 

J

Re: Fast Company talks about Vector Graphic Inc

[Brent Hilpert]

On 2015-Jul-23, at 6:56 AM, Christian Liendo wrote:
> 
> http://www.fastcompany.com/3047428/how-two-bored-1970s-housewives-helped-create-the-pc-industry



Nice writeup. I recall that picture of the two holding the VG1 appearing with a 
product release blurb in kilobaud circa 1977.

My Vector Graphic MG is functioning with it's original giant screw-top filter 
caps.

RE: PDP 11 gear finally moved

[tony duell]

> 
> * I once talked to a power supply guy about over-voltage sensors and
> the like, and he said that over-voltage conditions (like a power
> supply freaking out and giving TTL 8 Volts or something) due to
> component failures are exceedingly rare. When it does happen, it is
> almost always due to human error - mis-installing sense lines,
> cranking a trimmer too far, setting line voltage improperly, and so
> forth.

This is presumably why all decent PSUs, even those without remote sensing,
without twiddlepots to set the output voltage, etc, have crowbars. Manufacturers
do not fit components for no good reason.

I've had several instances where a PSU has 'gone crazy' in use. One time it was
a dry joint on the sense resistor. Another was in a simple 3-terminal
regualtor circuit where the common wire fell off the regulator [1]. The last
which has happened several times, applies to common switch-mode designs,
if the output smoothing capacitor goes high ESR (or in once case there was a
bad VIA connecting it to the rest of the PSU -- and on an HP board at that) you
get spike on the output of several times the desired output voltage.

[1] 5A regulators are often in TO3 metal cans and the +ve one has the common 
connection
to the case. If this is made by a solder tag under a fixing screw and said 
screw works
loose then the output voltage can go sky-high. A neat trick if possible (i.e. 
when there
is a separate input transsformer secondary/rectifier/smoothing cap for each 
regulator) is
to put a tag under each fixing screw, input -ve to one, output -ve (system 
ground) to
the other. Then if either screw comes loose you get no output as the circuit is 
opened.

-tony



--
Will

Re: PDP 11 gear finally moved

[William Donzelli]

> I proposed it, and was willing to build microcontroller-based boards
> and write firmware, but IIRC it was decided that there was too little
> benefit.

That seems odd, considering the lengths you guys took on the caps, and
the whole museum mentality of keeping things "safe" for the artifacts.
Microcontrollers and such probably are too complex - simple
over-voltage* and over-current circuits to trip the EPO (or whatever
DEC called it when the line was cut) would suffice, and give some of
the more delicate components a fighting chance of survival.

* I once talked to a power supply guy about over-voltage sensors and
the like, and he said that over-voltage conditions (like a power
supply freaking out and giving TTL 8 Volts or something) due to
component failures are exceedingly rare. When it does happen, it is
almost always due to human error - mis-installing sense lines,
cranking a trimmer too far, setting line voltage improperly, and so
forth.

--
Will

Re: Chromatics on ebay

[william degnan]

I told him he might get $500 in untested condition, a lot more if it
works.  Video, good pics, be ready with a ship quote, etc.   He may have
asked more than just me, but that is what I told him
On Jul 23, 2015 12:31 PM, "Josh Dersch"  wrote:

> It was me.  Despite the listing being "local pickup only" the description
> notes that the seller's willing to arrange shipping (it just won't be
> cheap).  So I put in a lowball bid on it.  Did not expect to be the high
> bidder, definitely did not expect to be the only bidder.
>
> That said, immediately after the auction ended, the seller contacted me
> and explained that he'd screwed up; he's new to eBay, couldn't figure out
> how to set a reserve (or an opening bid amount, apparently) and just
> couldn't let the thing go for $5.  Since I'm not completely heartless (just
> mostly) I'm trying to work something out with him, but we'll see; he seems
> to think it's worth a fortune -- I'm not so sure.  (Rare doesn't
> necessarily equate to worth and all that...)
>
> If I do end up with the system, I'll dump the ROMs, etc.
>
> - Josh
>
>
> On 7/23/15 7:24 AM, Al Kossow wrote:
>
>> did anyone here get this?
>>
>> http://www.ebay.com/itm/281752359535
>>
>> I am interested in a firmware dump, but not enough to drive to socal to
>> get it.
>>
>>
>>
>

Re: PDP 11 gear finally moved

[Eric Smith]

On Thu, Jul 23, 2015 at 12:06 AM, William Donzelli  wrote:
> Did the team ever consider some sort of active monitoring of the
> power, beyond whatever DEC implemented?

I proposed it, and was willing to build microcontroller-based boards
and write firmware, but IIRC it was decided that there was too little
benefit.

Re: Chromatics on ebay

[Josh Dersch]

It was me.  Despite the listing being "local pickup only" the 
description notes that the seller's willing to arrange shipping (it just 
won't be cheap).  So I put in a lowball bid on it.  Did not expect to be 
the high bidder, definitely did not expect to be the only bidder.


That said, immediately after the auction ended, the seller contacted me 
and explained that he'd screwed up; he's new to eBay, couldn't figure 
out how to set a reserve (or an opening bid amount, apparently) and just 
couldn't let the thing go for $5.  Since I'm not completely heartless 
(just mostly) I'm trying to work something out with him, but we'll see; 
he seems to think it's worth a fortune -- I'm not so sure.  (Rare 
doesn't necessarily equate to worth and all that...)


If I do end up with the system, I'll dump the ROMs, etc.

- Josh


On 7/23/15 7:24 AM, Al Kossow wrote:

did anyone here get this?

http://www.ebay.com/itm/281752359535

I am interested in a firmware dump, but not enough to drive to socal 
to get it.

Re: EPROM image for Xylogics 472 (multibus Pertec controller)?

[Jon]

Hello,

Sorry to revive this old discussion but I'm having problems with getting a
Xylogics 472 board recognized when probing the Multibus.
I'm hoping that maybe it's bitrot in the EPROM since that would be an
easy fix. I dumped my current one (180-001-957 rev A I think it says, the
label is pretty scratched up...) and at least it's not all ones, but without
something to compare it with, it's pretty difficult to say if it's damaged...
Would anyone out there be kind of enough to provide with me with
another image?

-Jon


On Fri, Dec 19, 2014 at 8:19 PM, Josh Dersch  wrote:
> Thanks, Al (and everyone else).  Looks like I'm all set here.
>
> - Josh
>
> On Thu, Dec 18, 2014 at 2:03 PM, Al Kossow  wrote:
>>
>> On 12/18/14 1:23 PM, r.stricklin wrote:
>>
>>>
>>> On Dec 18, 2014, at 12:37 PM, Earl Baugh wrote:
>>>
>>>  I'll try to check tonight when I get home... spreadsheet says I have 8
 Xylogics SMD controllers... have to see if any is an XY472.

>>>
>>> The XY472 is a Pertec-interface 1/2" tape controller. Not SMD.
>>>
>>> ok
>>> bear.
>>>
>>>
>>>
>> I have that and a XY450 dumped
>>
>>
>>
>>

Re: Chromatics on ebay

[Sean Caron]

Geography matters ... if you're in the right area, say, near a university
with a historically high computer science impact, or large high-tech
industries ... you can find a lot of equipment for free or very low cost
since the density was high and you're well situated to inexpensively pick
up large items ... other places, you've got to ship almost anything
interesting in, and when things start getting large and heavy, the price
runs up quick; it starts to cost real money to prep and move tonnage ... if
there are any constants to collecting computers, this is one of them.

Best,

Sean


On Thu, Jul 23, 2015 at 11:32 AM, william degnan 
wrote:

> I told the person that they will get more $$ if they prepare in
> advance to ship, etc.  People don't care and /or are lazy sometimes.
> b
>
> On Thu, Jul 23, 2015 at 11:21 AM, Bill Sudbrink 
> wrote:
> >> I spoke with the person, told him it was historic, looked up some info
> >> on the machine and when it was produced, etc.  VERY surprised it sold
> >> for $5.  Total bargain.
> >
> > That's what "local pickup only" will do to an auction.
> > There's a Vector MZ for 99 cents right now for the same reason.
> >
> > Bill S.
> >
> >
>
>
>
> --
> Bill
> vintagecomputer.net
>

Re: Chromatics on ebay

[william degnan]

I told the person that they will get more $$ if they prepare in
advance to ship, etc.  People don't care and /or are lazy sometimes.
b

On Thu, Jul 23, 2015 at 11:21 AM, Bill Sudbrink  wrote:
>> I spoke with the person, told him it was historic, looked up some info
>> on the machine and when it was produced, etc.  VERY surprised it sold
>> for $5.  Total bargain.
>
> That's what "local pickup only" will do to an auction.
> There's a Vector MZ for 99 cents right now for the same reason.
>
> Bill S.
>
>



-- 
Bill
vintagecomputer.net

RE: Chromatics on ebay

[Bill Sudbrink]

> I spoke with the person, told him it was historic, looked up some info
> on the machine and when it was produced, etc.  VERY surprised it sold
> for $5.  Total bargain.

That's what "local pickup only" will do to an auction.
There's a Vector MZ for 99 cents right now for the same reason.

Bill S.

Re: Chromatics on ebay

[william degnan]

I spoke with the person, told him it was historic, looked up some info
on the machine and when it was produced, etc.  VERY surprised it sold
for $5.  Total bargain.
b

On Thu, Jul 23, 2015 at 10:24 AM, Al Kossow  wrote:
> did anyone here get this?
>
> http://www.ebay.com/itm/281752359535
>
> I am interested in a firmware dump, but not enough to drive to socal to get
> it.
>



-- 
Bill
vintagecomputer.net

Chromatics on ebay

[Al Kossow]

did anyone here get this?

http://www.ebay.com/itm/281752359535

I am interested in a firmware dump, but not enough to drive to socal to get it.

Re: PDP 11 gear finally moved

[Noel Chiappa]

> From: Lyle Bickley 

> we tested each capacitor for capacitance and ESR
>  ...
> Each power supply had to meet it's specifications .. (every test was
> logged and documented).
> ...
> Every year we do a complete DEC specified preventative maintenance on
> the PDP-1 which includes testing every power supply for voltage,
> stability and ripple. 

When you tested the caps, did you all write down all the results? (I see you
logged the power supply results, so I'm guessing you all likely did for the
caps too, but you didn't say explicitly.) You all haven't by any chance gone
back and re-measured any of those caps, have you? (Again, standard PM likely
doesn't include measuring individual components - although if you're not
seeing any drift in the results, that's likely a sign that the components
aren't 'evolving'.)

If so, that would be really informative data about the longevity of these
particular electrolytics.

I say "these particular" because I'm starting to suspect that different
electrolytics behave differently - likely because of fine details of internal
construction, chemistry, etc. And it might even be details that the
manufacturers were not aware of.

I am reminded of a story (which I don't have time to chase down, to make sure
I have the details right) from the SR-71, or maybe it was some NASA gear.
Things all of a sudden started to fail in a way they had not before; after a
great deal of investigation, it turned out something really minor had changed
in the water supply to the manufacturing facility (perhaps they had started
doing municipal fluoridation, I think).

Noel

Fast Company talks about Vector Graphic Inc

[Christian Liendo]

http://www.fastcompany.com/3047428/how-two-bored-1970s-housewives-helped-create-the-pc-industry

Offered: Amiga 500/2000 BASIC manual, in German

[Liam Proven]

In honour of the 30th anniversary. Anyone want this handbuch? In good
condition, some staining on front cover but no dog-ears or creases.

Free for the cost of postage from the Czech Republic.


-- 
Liam Proven • Profile: http://lproven.livejournal.com/profile
Email: lpro...@cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lpro...@hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven
Cell/Mobiles: +44 7939-087884 (UK) • +420 702 829 053 (ČR)

Looking for AM2900 evaluation and learning kit

[Jacek Greniger]

Hi,

Maybe somebody on the list have such a board in collection and want to sell
it.

It looks like this:
http://ferretronix.com/march/sbc/amd2900/2900_trainer_80.jpg

Cheers,
Jacek

Re: PDP 11 gear finally moved

[Johnny Billquist]

On 2015-07-23 07:09, Tothwolf wrote:

On Tue, 21 Jul 2015, Lyle Bickley wrote:

On Mon, 20 Jul 2015 23:14:36 -0600 Eric Smith  wrote:

On Mon, Jul 20, 2015 at 4:46 PM, Rich Alderson
 wrote:


industry white papers with tables of decay rates for the aluminum
electrolytics that indicate that, *no matter what*, they lose
capacitance over time, until c. 14 years from manufacturer date they
are at 10% of rating.


That's very interesting. I haven't seen those white papers, but the
"no matter what" must in fact depend on something, since on the PDP-1
Restoration Project we found that most of the 40 year old aluminum
electrolytic capacitors still met their original specifications,
including capacitance within rated tolerance. Of the few electrolytic
capacitors that had failed, the problem was a catastrophic failure,
not the capacitance being outside the rated tolerance.

In the PDP-1, we preferred to keep the original components as much as
possible. Had there been a capacitor, the failure which would have
caused extensive damage to other components, we would have given
serious consideration to replacing it. However, that was not the case
for any of the capacitors in the PDP-1.

Had our analysis indicated any expected benefit to replacing all of
the electrolytic capacitors, we would have done so, and bagged and
tagged the originals similar to what we did with failed components,
so that they could be replaced if it ever was desired to return the
artifact to its pre-restoration condition.

I'm not recommending against LCM's policy, but I also wouldn't
necessarily encourage anyone to adopt it, nor to adopt the practices
of the CHM PDP-1 Restoration Project, without studying the issue.


As Eric, I'm a member of the PDP-1 Restoration Team. The PDP-1
restoration was completed in 2005 - and annually we check the power
supplies for voltage, ripple, etc. Not one of the re-formed capacitors
have failed in the ten years since the completion of the restoration.

I also re-formed all P/S capacitors in my PDP-8/S in September, 2013.
Not one has failed since...


How often is CHM's PDP-1 powered up and operated?

If LCM's computers are going to be powered up and used routinely, it
actually makes a lot of sense to go to the trouble to replace really old
aluminum electrolytics, even if they seem to test good, since doing so
is going to increase the reliability of frequently operated equipment.

This is the reason why /I/ replace aluminum electrolytics when I'm
making major repairs or fully reconditioning electronic equipment...I
want said electronic widget to be as reliable as possible because it is
never good when something breaks down while you are using it, especially
with gear which needs to run 24/7/365 for years and years at a time.

One example I can give are some Pentium P55C architecture (Socket 7)
systems which I've been running with minimal downtime for ~15 years. The
original power supplies with their original (and relatively low quality)
capacitors lasted about 15 to 17 years (I think the manufacture date
code stamped on the oldest one was 1998) before the systems began to
develop stability issues, requiring me to rebuild the power supplies
with new capacitors. I fully expect that the replacements would last
even longer than 20 years, however I rather doubt I'll be running those
computers by then.


I've mostly tried to stay out of this thread, as I both am no expert on 
electronics, and also seems to have a very different view and experience 
than many around here.


But I thought I should atleast give a datapoint for you all.

I'm no museum type of person. I try to run my stuff all the time. And I 
normally do. And I do not replace things in running, working machines. 
And since I keep running the machines, they keep running on their 
original parts. And they just keep working.


So I have various PDP-8 systems that have passed 40 years now, and they 
are still running fine. The same is true of my PDP-11 and VAX systems, 
that are now past 30 years. Running just fine.


The biggest problems have always been with gear that have been sitting 
unused for a long time, and I don't think I have ever had to replace any 
large capacitors. A few small ones, yes. And lots of transistors in 
power supplies. Those are the thing most often causing problems in the 
+5V bricks in larger PDP-11s in my experience.
But then again, I also have plenty of spares, so most of the time I have 
not bothered repairing them, and most spares sitting around have been 
fine, so the machines keep running.


Biggest problems with PS for me was a couple of VAX 6400 machines, where 
the power supplies developed issues in running systems. The machines 
have been scrapped. Didn't like systems that develop problems like that. 
8650 on the other hand is much better. But the external Unibus box 
currently have a power supply issue. But that machine (unfortunately had 
to sit a couple of years powered down, at which point it developed the 
problem).


S

Re: PDP 11 gear finally moved

[Lyle Bickley]

On Wed, 22 Jul 2015 09:01:35 -0400 (EDT)
j...@mercury.lcs.mit.edu (Noel Chiappa) wrote:

> > From: Tothwolf
> 
> > How do you know those aluminum electrolytic capacitors are functioning
> > just as good as they did when they were new? Unless you've tested them
> > out of circuit ...
> > ... aluminum electrolytic capacitors by their very electrochemical
> > nature degrade as they age and as they are used.
> 
> I am way out of my knowledge range in this discussion, but here's something I
> wanted to ask about: how do you reconcile this observation (assertion?) with
> the observations from several people (e.g. the PDP-1 people) that they _have_
> measured the electrolytics in their power supplies, and despite being N
> decades old (where N ~= 5), they are _still_ within specs? If the very nature
> of electrolytics mandates that they degrade, how are these still meeting
> specs?
> 
> I'm very confused...

This is the last time I'm going to discuss this subject.

IMHO, there's been way too much emotion expressed on what is a rather 
straightforward subject.

The PDP-1 team is composed of seasoned engineers. Combined we have over 250 
years of experience in high tech work and restoration. One Team member is a 
senior engineer at Tesla, two others are lead engineers in a different high 
tech medical startups/firms. Others of us are consultants to multiple Silicon 
Valley startups and companies. Almost all of us are serious vintage computer 
collectors.

The PDP-1 at the CHM is demoed regularly for the public - and we run Spacewar! 
tournaments every quarter which are "sold out" (there is no fee - just signup). 
The PDP-1 is also regularly demoed regularly by some of us for friends and 
special guests of the Museum (or personal friends). 

Since the PDP-1 at the CHM is the only running PDP-1 in the world - and the 
fact that the Museum considers it a highly significant artifact - we made 
restoration decisions with those factors in mind.

In accordance with standard Museum protocol, we tagged every bad part we 
removed from the PDP-1, bagged it and tagged it with the specific location it 
was removed from. We tagged all new (old stock) parts with a red dot. (In 
Museum protocol, one has to be able to restore an artifact to it's original 
condition - even if it is anticipated that will never occur). The CHM as other 
major Museums (like the Smithsonian) follow this protocol.

We spent months laying out the restoration plan for the PDP-1 - and then spent 
about six months restoring all the power supplies. We made the easy decision to 
reform the capacitors in the PDP-1 as they were all computer grade - and had 
not visually leaked or "dried out".

We used a very careful automated process to reform the capacitors which 
included a programmable power supply, current sensors and a laptop scripted to 
monitor the reformation progress. It was probably overkill - but we wanted to 
make sure we didn't overload any capacitor in the reformation process.

After reforming every capacitor in every power supply, we tested each capacitor 
for capacitance and ESR. Only four of the reformed capacitors did not pass 
these tests.

Two of us created an identical load test system that DEC had used to test the 
PDP-1 power supplies (multiple voltages, various currents, etc.). We then 
tested each power supply per DEC factory spec. starting at 85V and going as 
high as the spec. stated. Each power supply had to meet it's specifications in 
terms of voltage linearity and ripple (every test was logged and documented).

IIRC, the above process took almost six months. (While we were working on power 
supplies, others were working on restoring fans (total strip down and 
restoration), checking every soldered connection, etc., etc.

After we got the system up and passing all PDP-1 diagnostics - we went to work 
on the peripheral I/O gear - which took as long to restore as the PDP-1 CPU. 
The Model 30 display was particularly challenging. (We also reformed all the 
capacitors in the Model 30 display).

Subsequently to the complete restoration, We ran regular demos on the PDP-1 - 
and during the first year we had a few minor bugs crop up - mostly memory and 
display related.

The PDP-1 had been running demos for about 10 years and we've probably only had 
a handful of bogs over that period. We have NEVER had a P/S capacitor fail.

Every year we do a complete DEC specified preventative maintenance on the PDP-1 
which includes testing every power supply for voltage, stability and ripple. Of 
course we do many other tests as well - including running of all PDP-1 
diagnostics. Almost every year the PDP-1 passes all tests flawlessly.
--
Now to my own systems. For those of you who have checked my website, you'll see 
that I have a modestly large collection of systems. When I do restorations, I 
typically keep a logbook as we did on the CHM's PDP-1. I also reform all 
capacitors on my systems using a careful (but not as sophisti