Re: Looking for a document regarding PDP8

[Doug Jackson via cctalk]

Is it possible to share the link.

On Wed, 22 Apr. 2020, 3:38 pm Bob Smith via cctalk, 
wrote:

> I found the referenced paper, wrong authors - it was Bell and
> Casasent, in a cache paper, a bit earlier than 78
>
> On Thu, Apr 16, 2020 at 9:17 PM Bob Smith  wrote:
> >
> > Nice!
> > BUT  no my BigMac is a Mac Pro 1,1 tweaked with TB of disk with my old
> > files on it.
> > I call it BigMac cause it is about the same weight as the full chassis
> > PDP8/e I had at DEC that I lugged from one spot to another.
> > I did power it up and ran a number of searches, two more machines and
> > 8 more drives to search.
> > Thanks Al! Good Laugh!
> > bb
> >
> > On Thu, Apr 16, 2020 at 3:30 PM Al Kossow via cctalk
> >  wrote:
> > >
> > > On 4/16/20 10:12 AM, Bob Smith via cctalk wrote:
> > > > I am bout to pull out my BigMac that might
> > > > have the data in it.
> > >
> > > As in the Apple 68020 Rich Page computer?
> > > If so, I'd REALLY like to get a copy of the disk image
> > > to use on the BigMac that the museum has.
> > >
> > > https://www.computerhistory.org/collections/catalog/102747603
> > >
> > >
>

Re: Motorola EXORciser M6800 System

[osi.superboard via cctalk]

Hi David,

do you have Micromodule Manuals for the 6800 and 6809 single boards?

Cheers Thomas

Am 21.04.2020 um 17:30 schrieb David Christiansen via cctalk:

6800 manuals?

I think I have all the wanted manuals physical + a lot more on the 
boards..


Also a lot of the boards + an Exorciser 1 setup with CRT interface

Got a couple of ADDS Viewpoint terminals if somebody should be interested

It's a last call situation as I am creatin space for newer things

Introduced the 6800 system on the danish market as MOTA distributor 
from 1975


Best regards David Christiansen

Re: Looking for a document regarding PDP8

[Bob Smith via cctalk]

I found the referenced paper, wrong authors - it was Bell and
Casasent, in a cache paper, a bit earlier than 78

On Thu, Apr 16, 2020 at 9:17 PM Bob Smith  wrote:
>
> Nice!
> BUT  no my BigMac is a Mac Pro 1,1 tweaked with TB of disk with my old
> files on it.
> I call it BigMac cause it is about the same weight as the full chassis
> PDP8/e I had at DEC that I lugged from one spot to another.
> I did power it up and ran a number of searches, two more machines and
> 8 more drives to search.
> Thanks Al! Good Laugh!
> bb
>
> On Thu, Apr 16, 2020 at 3:30 PM Al Kossow via cctalk
>  wrote:
> >
> > On 4/16/20 10:12 AM, Bob Smith via cctalk wrote:
> > > I am bout to pull out my BigMac that might
> > > have the data in it.
> >
> > As in the Apple 68020 Rich Page computer?
> > If so, I'd REALLY like to get a copy of the disk image
> > to use on the BigMac that the museum has.
> >
> > https://www.computerhistory.org/collections/catalog/102747603
> >
> >

Re: Great, my VT52 is shot.

[Brent Hilpert via cctalk]

On 2020-Apr-21, at 8:35 PM, Chris Zach wrote:
>> The D8 5V ref and the targetted output V are divided via R15 and R17,R18 to 
>> provide the sense input at E2.2.
>> If one does the R ratio of the three resistors, it comes out, as would be 
>> expected, to ~ 0V.
> 
> Ah hah, that is clever. I wonder if the .8 volts means the output is higher 
> than what should be expected and the op amp isn't amping down or something. 
> However if the op amp was blown it should just allow full voltage through. 
> Maybe (is there a crowbar circuit in there).
> 
>> I'm a little surprised there's that much difference between E2.2 & E2.3 ( 
>> (-0.022) - (-0.8) ) without sending the E2 output off to +V, but not sure 
>> how much device variability to expect normally.
> 
>> You might look for the on-board values of R15,17,18. If they have been 
>> changed from those values specified in the schematic, then the -12 may have 
>> been changed to -15 (could do the ratio calc).
> 
> I tried measuring the resistance in circuit, but that never works. It's 
> possible they are measuring out properly and that .6 volts is the 
> representation of too much voltage at the output side (-15 instead of the 
> expected -12).

Look at the marked (as opposed to measured) values of the (3) installed Rs, to 
see if they have been intentionally changed in a revision to alter the output V.


>> Also what is the V at Q4.E (should be ~ +2.6V), also Q4.B & C.
> 
> I'll check that tomorrow. Connecting Q4.E to B did bring the output voltage 
> down to pretty much zero so that does seem to work.

When Q4.BE shorted, E2.6 should swing well-negative.


> If I can't figure this out I might just pull Q10 and put a 7912 in its place. 
> One chip does the whole job of regulating the output, end of story. Bad me of 
> course, but what the heck and if the display came up I would know where the 
> problem was.
> 
> If it turns out the op amp is dead, would a 741 work as a replacement?

Note comment lower left corner of schematic page.

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

The D8 5V ref and the targetted output V are divided via R15 and R17,R18 to 
provide the sense input at E2.2.
If one does the R ratio of the three resistors, it comes out, as would be 
expected, to ~ 0V.


Ah hah, that is clever. I wonder if the .8 volts means the output is 
higher than what should be expected and the op amp isn't amping down or 
something. However if the op amp was blown it should just allow full 
voltage through. Maybe (is there a crowbar circuit in there).



I'm a little surprised there's that much difference between E2.2 & E2.3 ( 
(-0.022) - (-0.8) ) without sending the E2 output off to +V, but not sure how much 
device variability to expect normally.



You might look for the on-board values of R15,17,18. If they have been changed 
from those values specified in the schematic, then the -12 may have been 
changed to -15 (could do the ratio calc).


I tried measuring the resistance in circuit, but that never works. It's 
possible they are measuring out properly and that .6 volts is the 
representation of too much voltage at the output side (-15 instead of 
the expected -12).



Also what is the V at Q4.E (should be ~ +2.6V), also Q4.B & C.


I'll check that tomorrow. Connecting Q4.E to B did bring the output 
voltage down to pretty much zero so that does seem to work.


If I can't figure this out I might just pull Q10 and put a 7912 in its 
place. One chip does the whole job of regulating the output, end of 
story. Bad me of course, but what the heck and if the display came up I 
would know where the problem was.


If it turns out the op amp is dead, would a 741 work as a replacement?

Re: Great, my VT52 is shot.

[Brent Hilpert via cctalk]

On 2020-Apr-21, at 5:27 PM, Chris Zach via cctalk wrote:
> Meantime reading the manual I found an interesting test: If you short emitter 
> to base on Q4 (easiest way is to jumper diode D10) the voltage on the -12v 
> supply goes to .4 volts. They're saying it's E2, R15,R17,R14.
> 
> Is there a way I can test the op-amp in circuit? Maybe it's dead.


The three regulators are all referenced via D8 (~ +5V).

Circuit-wise, for the -12, 0V/GND is the reference input at E2.3.
The D8 5V ref and the targetted output V are divided via R15 and R17,R18 to 
provide the sense input at E2.2.
If one does the R ratio of the three resistors, it comes out, as would be 
expected, to ~ 0V.

I'm a little surprised there's that much difference between E2.2 & E2.3 ( 
(-0.022) - (-0.8) ) without sending the E2 output off to +V, but not sure how 
much device variability to expect normally.

You might look for the on-board values of R15,17,18. If they have been changed 
from those values specified in the schematic, then the -12 may have been 
changed to -15 (could do the ratio calc).

Also what is the V at Q4.E (should be ~ +2.6V), also Q4.B & C.


> On 4/21/2020 5:36 PM, Chris Zach via cctalk wrote:
>> Ok, some test results below.
>> 1) Are we sure J2-2 should be -12? It really seems to like being -15.
>> 2) The voltage across the zener diode there is a nice solid -3.8-3.9v. It 
>> appears to be a germanium diode (.1v drop across, both directions) I could 
>> disconnect it and see if that makes things better.
>> 3)

>> E2.2 is -.8 volts referenced to ground.
>> E2.3 is -22mv referenced to ground
>> E2.6 is around .6v. Ramps up from about .58 at startup to .61 then down to 
>> .60something. Note that is a positive voltage wrt ground.
>> Q12 was reading
>> -24.4v emitter
>> -15v collector
>> -23.8v base
>> Q12 does not have a CE short
>> What is this using as a reference to get the -12v from the transistor?

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

Meantime reading the manual I found an interesting test: If you short 
emitter to base on Q4 (easiest way is to jumper diode D10) the voltage 
on the -12v supply goes to .4 volts. They're saying it's E2, R15,R17,R14.


Is there a way I can test the op-amp in circuit? Maybe it's dead.

C


On 4/21/2020 5:36 PM, Chris Zach via cctalk wrote:

Ok, some test results below.

1) Are we sure J2-2 should be -12? It really seems to like being -15.
2) The voltage across the zener diode there is a nice solid -3.8-3.9v. 
It appears to be a germanium diode (.1v drop across, both directions) I 
could disconnect it and see if that makes things better.

3)


E2.2 and E2.3 should be around 0V.E2.2 is -.8 volts referenced to ground.

E2.3 is -22mv referenced to ground
E2.6 is around .6v. Ramps up from about .58 at startup to .61 then down 
to .60something. Note that is a positive voltage wrt ground.


Q12 was reading
-24.4v emitter
-15v collector
-23.8v base
Q12 does not have a CE short

What is this using as a reference to get the -12v from the transistor?

Maybe the zener is just out of spec. Can someone with a VT52 cross check 
my voltages to see if they are accurate?


Thanks all!



E2.6 I expect would normally be within +/- 2V of GND.
If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to 
throttle down the output but failing due to some failure around Q4/Q12.


Measure the voltages on Q4 and Q12.
They could be leaky or low-gain.
It's conceivable Q12 has a CE short, but I'd expect the input to the 
reg to be more than -15.


The low -5 is odd, zener D14 looks to be a 5.1V type.
R45 is probably burning up.
I haven't spotted anything in the schematic that actually uses the -5,
it looks to be provided for some alternative character generator 
(schematic pdf.42),
so that may depend on what character generator chip / daughter board 
is used in your unit.

Re: World's most frustrating FTGH giveaway - Palm Pilot box

[Paxton Hoag via cctalk]

Hi Mark,

I haven't looked a the Classic Computer List in a couple of months so
please forgive this late post. I would be interested in the box and
contents. I collect Palm Pilots and have one to put in the box.

If it is still available I could send you my address. I would be happy to
pay postage.

Paxton Hoag
Astoria Oregon

On Sat, Feb 29, 2020 at 9:46 PM Tapley, Mark B. via cctalk <
cctalk@classiccmp.org> wrote:

> All,
> Next to go is a box in which a Palm Pilot was originally sold.
>
> The box is in great shape, shrink-wrap intact except where it was sliced
> just enough to open the top.
> The manual is in great shape.
> The registration card is in great shape.
> The order receipt is in great shape, name of original owner mis-spelled
> but otherwise apparently correct.
> The accessories catalog is in great shape.
> The software on 3 each 3.5” floppies and on CD appears to be in great
> shape (not test-read yet).
> The Now Sync accessory software, on 2 more 3.5” floppies, appears to be in
> great shape.
> The leatherette protector is in great shape, with its foam insert still
> inside keeping it shaped for the Palm Pilot.
> The DE-9 to DB-25 serial port adaptor is in great shape.
> For Pete’s sake, the screen protector that peeled off the Palm Pilot
> screen is in great shape,
> lovingly tucked into the manual.
>
> You have probably noticed what is missing.
> There are no electronics included.
> No Palm Pilot, no charging/syncing cradle.
> G.
>
> You probably want this if you picked up the Palm Pilot at ShopGoodwill
> somewhere, want to re-create that 1997 “first on the block with a personal
> digital accessory” feeling and really enjoy going through the accessory
> paperwork.
>
> https://www.shopgoodwill.com/Item/87198940
>
> (but I think that is a different model).
>
> Free to a Good Home, preferably one with an actual Palm Pilot. Shipping
> will be from San Antonio TX, 78254. If as I suspect, nobody interested,
> headed to the trash. Standard rules, I’ll wait for a week or so, ship to
> the sender of the first email in my in-box or to Al K if he emails before I
> ship.
>
> - Mark
> 210-522-6025 office
> 210-379-4635 cell
>
>

-- 
Paxton Hoag
Astoria, OR
USA

Univac 490 Gallery Talk - 1963 Real Time Computer

[rar via cctalk]

The System Source Computer Museum is closed due to COVID-19, so we are making 
some video gallery talks.

Here is the first one:  

https://www.youtube.com/watch?v=hq7aVCc2GP8

The video describes some of the applications of this 57 year old computer 
including it original use at Goddard Space Flight Center

Bob Roswell
mus...@syssrc.com
https://museum.syssrc.com

Re: Motorola EXORciser M6800 System

[dwight via cctalk]

You should also ask on the vcf forum. There are a number of 6800 people there.
Dwight


From: cctalk  on behalf of David Christiansen 
via cctalk 
Sent: Tuesday, April 21, 2020 9:30 AM
To: cctalk@classiccmp.org 
Subject: Re: Motorola EXORciser M6800 System

6800 manuals?

I think I have all the wanted manuals physical + a lot more on the boards..

Also a lot of the boards + an Exorciser 1 setup with CRT interface

Got a couple of ADDS Viewpoint terminals if somebody should be interested

It's a last call situation as I am creatin space for newer things

Introduced the 6800 system on the danish market as MOTA distributor from
1975

Best regards David Christiansen


--
Denne e-mail blev kontrolleret for virusser af Avast antivirussoftware.
https://www.avast.com/antivirus

Re: Pdp11/05 boot media

[Malcolm Macleod via cctalk]

> Hi everybody

> 

> I'm the proud owner of a PDP11/05 system with a couple of 8" floppy
drives.  I believe they are likely to be RX01s.

> 

> Does anybody on the list have some boot media that they could provide.  I
understand that the controller can't format

> the disks so I'm in a frustrating state where I don't know where to start.

> 

> Doug Jackson

> 

> Canberra  Australia.

 

Hi Doug,

 

I'm in Melbourne and have several working PDP-11's.  I can send you a couple
of bootable RT11 8" disks.  I'll need to know whether they are RX01s or
RX02s though.  Perhaps send me an email offline and we can take it from
there?

 

Malcolm

www.avitech.com.au  

 

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

I wonder if I would go straight to hell if I just pulled the Q12 
transistor and wired in a 12 volt wall wart between ground (J2-2) and 
+12 (ground) to get -12


C

On 4/21/2020 5:36 PM, Chris Zach via cctalk wrote:

Ok, some test results below.

1) Are we sure J2-2 should be -12? It really seems to like being -15.
2) The voltage across the zener diode there is a nice solid -3.8-3.9v. 
It appears to be a germanium diode (.1v drop across, both directions) I 
could disconnect it and see if that makes things better.

3)


E2.2 and E2.3 should be around 0V.E2.2 is -.8 volts referenced to ground.

E2.3 is -22mv referenced to ground
E2.6 is around .6v. Ramps up from about .58 at startup to .61 then down 
to .60something. Note that is a positive voltage wrt ground.


Q12 was reading
-24.4v emitter
-15v collector
-23.8v base
Q12 does not have a CE short

What is this using as a reference to get the -12v from the transistor?

Maybe the zener is just out of spec. Can someone with a VT52 cross check 
my voltages to see if they are accurate?


Thanks all!



E2.6 I expect would normally be within +/- 2V of GND.
If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to 
throttle down the output but failing due to some failure around Q4/Q12.


Measure the voltages on Q4 and Q12.
They could be leaky or low-gain.
It's conceivable Q12 has a CE short, but I'd expect the input to the 
reg to be more than -15.


The low -5 is odd, zener D14 looks to be a 5.1V type.
R45 is probably burning up.
I haven't spotted anything in the schematic that actually uses the -5,
it looks to be provided for some alternative character generator 
(schematic pdf.42),
so that may depend on what character generator chip / daughter board 
is used in your unit.

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

Ok, some test results below.

1) Are we sure J2-2 should be -12? It really seems to like being -15.
2) The voltage across the zener diode there is a nice solid -3.8-3.9v. 
It appears to be a germanium diode (.1v drop across, both directions) I 
could disconnect it and see if that makes things better.

3)


E2.2 and E2.3 should be around 0V.E2.2 is -.8 volts referenced to ground.

E2.3 is -22mv referenced to ground
E2.6 is around .6v. Ramps up from about .58 at startup to .61 then down 
to .60something. Note that is a positive voltage wrt ground.


Q12 was reading
-24.4v emitter
-15v collector
-23.8v base
Q12 does not have a CE short

What is this using as a reference to get the -12v from the transistor?

Maybe the zener is just out of spec. Can someone with a VT52 cross check 
my voltages to see if they are accurate?


Thanks all!



E2.6 I expect would normally be within +/- 2V of GND.
If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to throttle 
down the output but failing due to some failure around Q4/Q12.

Measure the voltages on Q4 and Q12.
They could be leaky or low-gain.
It's conceivable Q12 has a CE short, but I'd expect the input to the reg to be 
more than -15.

The low -5 is odd, zener D14 looks to be a 5.1V type.
R45 is probably burning up.
I haven't spotted anything in the schematic that actually uses the -5,
it looks to be provided for some alternative character generator (schematic 
pdf.42),
so that may depend on what character generator chip / daughter board is used in 
your unit.

Re: pdp11/84 PMI memory: What is the problem with Q bus?

[Chris Zach via cctalk]

Thanks Mark! Actually this was just the boards from the 11/84 (no idea 
what happened to the chassis, drat) so it's an 11/84 CPU (18mhz, FPP 
chip installed), 2 PMI boards (one old 2mb, one new 1mb) a console board 
of some sort and the Unibus map.


I popped this into my BA23 to speed things up a bit in place of my quad 
height 11/73 CPU with 2mb memory. So far it seems to work, and with the 
CA memory in the PMI slot managed to boot RSX11M 4.2 and compile up EMPIRE.


My guess is the 11/84's Unibus talks directly to the PMI bus and 
orchestrates the data transfers, but there is something wrong when the 
PMI memory is accessed on the true Q bus. That would not happen on an 
11/84 (CPU and Map use PMI only) but when you have a Q bus DMA device it 
probably manifests at random. It's possible the MTI card is throttling 
the DMA to single mode instead of hog mode, wonder if I want to screw up 
my disk to verify this


Drat. On the positive side it's chock full of 256k chips, which I could 
pull off and put on the EA board to bring it up to 2mb memory. I have 
air heat tools and a pre-heater so getting the chips off should be 
pretty basic. Getting them on the new board though could be a pain since 
all the holes are soldered over


No way to reprogram or fix it I assume?

C

On 4/21/2020 11:48 AM, Mark Matlock via cctalk wrote:


Date: Sun, 19 Apr 2020 15:29:44 -0400
From: Chris Zach 
To: CCTalk mailing list 
Subject: pdp11/84 PMI memory: What is the problem with Q bus?
Message-ID: <3efa4105-3d3d-bb98-0358-8c46fca0f...@alembic.crystel.com>
Content-Type: text/plain; charset=utf-8; format=flowed

So I picked up an 11/84 CPU, 3mb of memory, and a 11/84 Unibus card on
Ebay. Goal is to speed up my fastest 11 here

For boot time, the diagnostics run in 13 seconds (from when it starts to
prompt) on the 11/73 board I have and 13 seconds on the 11/84 board.
This is with a camintonn 2mb half height memory board.

Put in the first PMI module above the 11/84 CPU and tried it out. This
is a CA rev board which apparently only works in a Unibus pdp11 and not
a Q-bus one. Apparently it does work.

So what exactly was the bug with the older PMI memory? Block mode DMA,
I'm using an MTI ESDI controller which can do 16 word block DMA on Q
Bus. Something else?



Chris,
   Congrats on the PDP-11/84! I also have a PDP-11/84 that uses one of Joerg’s 
Hoppe’s
UniBone devices to simultaneously emulate MSCP disks, RL02 disks (including the
RL02 Load/Ready/WriteProtect/ and fault lights) and a DL11.

   I have a question about something you said above, that you are using a MTI
ESDI disk controller and then you mention Qbus block mode DMA. Are you able to 
use a
Qbus MTI controller in the 11/84’s Qbus section of the backplane? This is 
something
I’ve often wondered about but never tried.

  Also, you mention putting the PMI memory above the 11/84 CPU. In the 11/83
Qbus backplane this is of course determines whether the M8637 memory is 
accessed via
Q22 or PMI. In the 11/84 System Maintenance Guide Figure 2-8 shows the
CPU card above the memory which if you were to do this in the 11/83 would mean
that the memory will be accessed via Q22 and essentially become an 11/73.
In my 11/83 I have run both configurations to understand and measure the 
benefit of PMI.

   As has been mentioned the 11/84 can use any of the M8637 memory boards but 
the
11/83 can only use the M8637-D or -E versions. For anyone who is curious about 
what
Happens when a M8637-C version board is used as PMI memory in an 11/83 I can 
speak
 From experience. This was running RSX11M+ and it boots fine but after a few 
minutes if
The system is active, the console starts to report that various installed tasks 
are corrupted
And the system will XDT a bit later. After this the disk is corrupted and you 
will need to restore
the system disk from backups after you get the correct PMI memory boards.

   I’m not completely sure how the write DMA operations put bad data through 
the disk controller
(I was using an Emulex UC07 with a SCSI2SD) into the disks but that is what 
happens.

Mark Matlock

Re: Pdp11/05 boot media

[Torfinn Ingolfsen via cctalk]

On Tue, Apr 21, 2020 at 4:32 PM Chuck Guzis via cctalk
 wrote:
>
> Yes, that's assuming you have a PC with an FDC capable of
> writing/formatting FM floppies.
>
> --Chuck

Since nobody has mentioned it in this thread already Dave Dunfield's
TestFDC is good for finding out if the FDC in a PC is capable.
Downloadable here: http://www.classiccmp.org/dunfield/img/index.htm
(Chuck knows this of course, but the OP might not)

HTH, HAND, stay safe.
-- 
Regards,
Torfinn Ingolfsen

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

It's conceivable there was a revision change where the -12V was changed to 
-15V, but it does seem unlikely.

The -12 is used by the vertical deflection circuit, the CRT filament, (and the 
RS-232).


Well, vertical deflection seems to be my problem so this may make sense.

Until I figure this out I'm going to pull that jumper to remove power 
from the HV circuits. I'm guessing the circuit can regulate with no load.



E2.2 and E2.3 should be around 0V.
E2.6 I expect would normally be within +/- 2V of GND.
If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to throttle 
down the output but failing due to some failure around Q4/Q12.

Measure the voltages on Q4 and Q12.
They could be leaky or low-gain.
It's conceivable Q12 has a CE short, but I'd expect the input to the reg to be 
more than -15.


*nod* I just took a look at Q12 and it's not shorted which is good. It 
looks to be the regulator power transistor, the other components vary 
the base to keep the voltage at the output constant under load. The 
input voltage to the circuit is around -24v so it looks like the 
rectifier diodes are ok enough.



The low -5 is odd, zener D14 looks to be a 5.1V type.


Yeah, that is really odd, especially if -5v isn't really used. I wonder 
if the zener diode is shorted, that could cause all sorts of weirdness. 
I'll check.


C

pdp11/84 PMI memory: What is the problem with Q bus?

[Mark Matlock via cctalk]

> 
> Date: Sun, 19 Apr 2020 15:29:44 -0400
> From: Chris Zach 
> To: CCTalk mailing list 
> Subject: pdp11/84 PMI memory: What is the problem with Q bus?
> Message-ID: <3efa4105-3d3d-bb98-0358-8c46fca0f...@alembic.crystel.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> So I picked up an 11/84 CPU, 3mb of memory, and a 11/84 Unibus card on 
> Ebay. Goal is to speed up my fastest 11 here
> 
> For boot time, the diagnostics run in 13 seconds (from when it starts to 
> prompt) on the 11/73 board I have and 13 seconds on the 11/84 board. 
> This is with a camintonn 2mb half height memory board.
> 
> Put in the first PMI module above the 11/84 CPU and tried it out. This 
> is a CA rev board which apparently only works in a Unibus pdp11 and not 
> a Q-bus one. Apparently it does work.
> 
> So what exactly was the bug with the older PMI memory? Block mode DMA, 
> I'm using an MTI ESDI controller which can do 16 word block DMA on Q 
> Bus. Something else?


Chris,
  Congrats on the PDP-11/84! I also have a PDP-11/84 that uses one of Joerg’s 
Hoppe’s 
UniBone devices to simultaneously emulate MSCP disks, RL02 disks (including the 
RL02 Load/Ready/WriteProtect/ and fault lights) and a DL11.

  I have a question about something you said above, that you are using a MTI 
ESDI disk controller and then you mention Qbus block mode DMA. Are you able to 
use a 
Qbus MTI controller in the 11/84’s Qbus section of the backplane? This is 
something 
I’ve often wondered about but never tried. 

 Also, you mention putting the PMI memory above the 11/84 CPU. In the 11/83 
Qbus backplane this is of course determines whether the M8637 memory is 
accessed via 
Q22 or PMI. In the 11/84 System Maintenance Guide Figure 2-8 shows the 
CPU card above the memory which if you were to do this in the 11/83 would mean 
that the memory will be accessed via Q22 and essentially become an 11/73.
In my 11/83 I have run both configurations to understand and measure the 
benefit of PMI.

  As has been mentioned the 11/84 can use any of the M8637 memory boards but the
11/83 can only use the M8637-D or -E versions. For anyone who is curious about 
what
Happens when a M8637-C version board is used as PMI memory in an 11/83 I can 
speak
From experience. This was running RSX11M+ and it boots fine but after a few 
minutes if
The system is active, the console starts to report that various installed tasks 
are corrupted
And the system will XDT a bit later. After this the disk is corrupted and you 
will need to restore
the system disk from backups after you get the correct PMI memory boards.

  I’m not completely sure how the write DMA operations put bad data through the 
disk controller
(I was using an Emulex UC07 with a SCSI2SD) into the disks but that is what 
happens.

Mark Matlock

RE: pdp11/84 PMI memory: What is the problem with Q bus?

[Mark Matlock via cctalk]

> Date: Sun, 19 Apr 2020 15:29:44 -0400
> From: Chris Zach 
> To: CCTalk mailing list 
> Subject: pdp11/84 PMI memory: What is the problem with Q bus?
> Message-ID: <3efa4105-3d3d-bb98-0358-8c46fca0f...@alembic.crystel.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> So I picked up an 11/84 CPU, 3mb of memory, and a 11/84 Unibus card on 
> Ebay. Goal is to speed up my fastest 11 here
> 
> For boot time, the diagnostics run in 13 seconds (from when it starts to 
> prompt) on the 11/73 board I have and 13 seconds on the 11/84 board. 
> This is with a camintonn 2mb half height memory board.
> 
> Put in the first PMI module above the 11/84 CPU and tried it out. This 
> is a CA rev board which apparently only works in a Unibus pdp11 and not 
> a Q-bus one. Apparently it does work.
> 
> So what exactly was the bug with the older PMI memory? Block mode DMA, 
> I'm using an MTI ESDI controller which can do 16 word block DMA on Q 
> Bus. Something else?


Chris,
   Congrats on the PDP-11/84! I also have a PDP-11/84 that uses one of Joerg’s 
Hoppe’s 
UniBone devices to simultaneously emulate MSCP disks, RL02 disks (including the 
RL02 Load/Ready/WriteProtect/ and fault lights) and a DL11.

   I have a question about something you said above, that you are using a MTI 
ESDI disk controller and then you mention Qbus block mode DMA. Are you able to 
use a 
Qbus MTI controller in the 11/84’s Qbus section of the backplane? This is 
something 
I’ve often wondered about but never tried. 

  Also, you mention putting the PMI memory above the 11/84 CPU. In the 11/83 
Qbus backplane this is of course determines whether the M8637 memory is 
accessed via 
Q22 or PMI. In the 11/84 System Maintenance Guide Figure 2-8 shows the 
CPU card above the memory which if you were to do this in the 11/83 would mean 
that the memory will be accessed via Q22 and essentially become an 11/73.
In my 11/83 I have run both configurations to understand and measure the 
benefit of PMI.

   As has been mentioned the 11/84 can use any of the M8637 memory boards but 
the
11/83 can only use the M8637-D or -E versions. For anyone who is curious about 
what
Happens when a M8637-C version board is used as PMI memory in an 11/83 I can 
speak
From experience. This was running RSX11M+ and it boots fine but after a few 
minutes if
The system is active, the console starts to report that various installed tasks 
are corrupted
And the system will XDT a bit later. After this the disk is corrupted and you 
will need to restore
the system disk from backups after you get the correct PMI memory boards.

   I’m not completely sure how the write DMA operations put bad data through 
the disk controller
(I was using an Emulex UC07 with a SCSI2SD) into the disks but that is what 
happens.

Mark Matlock

Re: Motorola EXORciser M6800 System

[David Christiansen via cctalk]

6800 manuals?

I think I have all the wanted manuals physical + a lot more on the boards..

Also a lot of the boards + an Exorciser 1 setup with CRT interface

Got a couple of ADDS Viewpoint terminals if somebody should be interested

It's a last call situation as I am creatin space for newer things

Introduced the 6800 system on the danish market as MOTA distributor from 
1975


Best regards David Christiansen


--
Denne e-mail blev kontrolleret for virusser af Avast antivirussoftware.
https://www.avast.com/antivirus

Re: Great, my VT52 is shot.

[Hector Peraza via cctalk]

The raster seems folded at the left and at the top, which indicates a 
problem with both the vertical and horizontal sweep.


As Mattis Lind already mentioned, the VT52 uses direct drive of the 
vertical and horizontal circuitry (no oscillators to synchronize) yet 
the character rows in the video are running diagonally totally out of 
sync with the sweep, so I'd check the timing generator (pages 4-17 and 
4-18 of the Maintenance Manual, pages 19-21 of the Schematics PDF). But 
that's after checking that the power voltages are solid and ripple-free. 
I'd also check a few components around the horizontal output stage, e.g. 
if capacitor C44 goes bad (page 10) then the pulses from the horizontal 
output will get into other parts of the circuit via the power supply 
lines and/or the driver stages, affecting the logic's work.


A final note: don't keep the terminal running like that for a long time, 
since the horizontal frequency is out of specs the fly-back can get 
damaged (the core can saturate, increasing the current drawn; that may 
also explain the noise you're hearing).


Hector.


On 4/20/2020 7:40 PM, Mattis Lind via cctalk wrote:

I looked at the video once more and paused around 0:21. It appears to be
some text there on the uppermost row.

Maybe the vertical sweep is highly non-linear. Check all capacitors in the
vertical stage. C43, C41,C40, C42, C35 and C45. Would probably be good to
measure the voltage over the current sensing resistor R73 and see if it is
a proper ramp as it should.

What about the R92 linearity potentiometer. Is it ok? Diode D31? Actually
check all semiconductors.

/Mattis

måndag 20 april 2020 skrev Mattis Lind :






Something else that might help with diagnosis is taking pictures of the
screen with known, simple elements on the screen.
e.g.:
 - clear the screen
 - take pic if it doesn't clear
 - type a simple character like a "-"or "1"
 - pic
 - type a half line or full line of characters
 - pic
 - type different characters on two different lines
 - pic

The idea being to find out, from simple known patterns, where the pixels
end up being displayed,
so it may be possible to figure out what's happening with the scan,
whether it's getting stretched, folding over, etc.




That is a good idea. Loop the terminal and create a bunch of "known
references".

Might add that it would be interesting to see one single character on a
lets say 4 different positions. Column 0, Column 20, Column 40 and end of
line. Approximately since it is hard to be exact.

/Mattis




--
Hector Peraza
BrightSpec NV/SA
Waterfront Researchpark
Galileilaan 15 (Darwin)
2845 Niel
BTW/VAT: BE 0846.102.393
http://www.brightspec.be

Re: Great, my VT52 is shot.

[Brent Hilpert via cctalk]

On 2020-Apr-21, at 7:57 AM, Chris Zach via cctalk wrote:
> Well I'm starting to walk through this. First I took an IR picture of the 
> boards in operation, then started troubleshooting.
> 
> First I started checking voltages. J2 is easily accessible so I put a ground 
> probe on pin 10, and checked voltages as follows:
> 
> J2-3 Should be -5v, reading -3.8v
> J2-2 Should be -12v reading -15v
> J2-4 Should be 5v, reading 5.04v
> J1-10 Should be 15v reading 14.84
> 
> Hm. That's odd. Looks like the negative voltages are a bit off.
> 
> According to the schematic the key transistor on the 5v rail is Q6, which is 
> a 2n3055. The key transistor on +15 is Q10 and that circuit looks ok. However 
> whatever is running the -5 and -12 volts is not working right Looks like 
> Q12 is the key power transistor there with E2 serving as the control.
> 
> Hm

It's conceivable there was a revision change where the -12V was changed to 
-15V, but it does seem unlikely.

The -12 is used by the vertical deflection circuit, the CRT filament, (and the 
RS-232).

I wouldn't immediately anticipate -12 going to -15 alone would produce the 
upset you're seeing on the screen but there could well be interrelated failures 
between the vertical deflection and the over-voltage -12, so the excessive -12 
should probably be addressed.

In the power supply, you could measure some voltages around the -12 regulator.

E2.2 and E2.3 should be around 0V.
E2.6 I expect would normally be within +/- 2V of GND.
If E2.6 is way-positive (>Q4.E, > ~ +2.6V), then E2 is attempting to throttle 
down the output but failing due to some failure around Q4/Q12.

Measure the voltages on Q4 and Q12.
They could be leaky or low-gain.
It's conceivable Q12 has a CE short, but I'd expect the input to the reg to be 
more than -15.

The low -5 is odd, zener D14 looks to be a 5.1V type.
R45 is probably burning up.
I haven't spotted anything in the schematic that actually uses the -5,
it looks to be provided for some alternative character generator (schematic 
pdf.42),
so that may depend on what character generator chip / daughter board is used in 
your unit.

RE: HP 41-CX

[jwest--- via cctalk]

I'm very fond of my hp41c and still use it every day. When I had a minor 
problem with it, I sent it here and they did a fantastic job for what I 
considered a very reasonable price:

https://vintagecalculatorrepair.com/

If you want to DIY and your issues are solely the battery compartment, see:

https://www.thecalculatorstore.com/Calculator-blog/HP-41C-repair-kit

J

Re: Great, my VT52 is shot.

[Chris Zach via cctalk]

Well I'm starting to walk through this. First I took an IR picture of 
the boards in operation, then started troubleshooting.


First I started checking voltages. J2 is easily accessible so I put a 
ground probe on pin 10, and checked voltages as follows:


J2-3 Should be -5v, reading -3.8v
J2-2 Should be -12v reading -15v
J2-4 Should be 5v, reading 5.04v
J1-10 Should be 15v reading 14.84

Hm. That's odd. Looks like the negative voltages are a bit off.

According to the schematic the key transistor on the 5v rail is Q6, 
which is a 2n3055. The key transistor on +15 is Q10 and that circuit 
looks ok. However whatever is running the -5 and -12 volts is not 
working right Looks like Q12 is the key power transistor there with 
E2 serving as the control.


Hm

C




On 4/20/2020 1:40 PM, Mattis Lind via cctalk wrote:

I looked at the video once more and paused around 0:21. It appears to be
some text there on the uppermost row.

Maybe the vertical sweep is highly non-linear. Check all capacitors in the
vertical stage. C43, C41,C40, C42, C35 and C45. Would probably be good to
measure the voltage over the current sensing resistor R73 and see if it is
a proper ramp as it should.

What about the R92 linearity potentiometer. Is it ok? Diode D31? Actually
check all semiconductors.

/Mattis

måndag 20 april 2020 skrev Mattis Lind :








Something else that might help with diagnosis is taking pictures of the
screen with known, simple elements on the screen.
e.g.:
 - clear the screen
 - take pic if it doesn't clear
 - type a simple character like a "-"or "1"
 - pic
 - type a half line or full line of characters
 - pic
 - type different characters on two different lines
 - pic

The idea being to find out, from simple known patterns, where the pixels
end up being displayed,
so it may be possible to figure out what's happening with the scan,
whether it's getting stretched, folding over, etc.




That is a good idea. Loop the terminal and create a bunch of "known
references".

Might add that it would be interesting to see one single character on a
lets say 4 different positions. Column 0, Column 20, Column 40 and end of
line. Approximately since it is hard to be exact.

/Mattis

Re: Pdp11/05 boot media

[Chris Zach via cctalk]

Or someone could lend you some floppies. I have an RX02 drive here I am 
putting back together, right now I have it switched to emulate an RX01 
with my RXV11 controller. I'll look through my floppies and see if I 
have some RX01 disks I can load up with RT11.


C

On 4/21/2020 10:15 AM, Chuck Guzis via cctalk wrote:

On 4/21/20 5:02 AM, Bill Degnan via cctalk wrote:

Using an older version OS and PDPGUI send a tape image into RAM through the
serial port.  Helps if you have a m9312 ROM board.  You can make rx01 disks
using dunfield's disk utility (right?) I believe but I never actually did


Yes, that's assuming you have a PC with an FDC capable of
writing/formatting FM floppies.

--Chuck

Re: Pdp11/05 boot media

[Chuck Guzis via cctalk]

On 4/21/20 5:02 AM, Bill Degnan via cctalk wrote:
> Using an older version OS and PDPGUI send a tape image into RAM through the
> serial port.  Helps if you have a m9312 ROM board.  You can make rx01 disks
> using dunfield's disk utility (right?) I believe but I never actually did

Yes, that's assuming you have a PC with an FDC capable of
writing/formatting FM floppies.

--Chuck

Re: Pdp11/05 boot media

[Bill Degnan via cctalk]

Using an older version OS and PDPGUI send a tape image into RAM through the
serial port.  Helps if you have a m9312 ROM board.  You can make rx01 disks
using dunfield's disk utility (right?) I believe but I never actually did
this myself.

Bill

On Tue, Apr 21, 2020, 5:35 AM Doug Jackson via cctalk 
wrote:

> Hi everybody
>
> I'm the proud owner of a PDP11/05 system with a couple of 8" floppy
> drives.  I believe they are likely to be RX01s.
>
> Does anybody on the list have some boot media that they could provide.  I
> understand that the controller can't format the disks so I'm in a
> frustrating state where I don't know where to start.
>
> Doug Jackson
>
> Canberra  Australia.
>

Pdp11/05 boot media

[Doug Jackson via cctalk]

Hi everybody

I'm the proud owner of a PDP11/05 system with a couple of 8" floppy
drives.  I believe they are likely to be RX01s.

Does anybody on the list have some boot media that they could provide.  I
understand that the controller can't format the disks so I'm in a
frustrating state where I don't know where to start.

Doug Jackson

Canberra  Australia.

Re: HP 41-CX

[Doug Jackson via cctalk]

Hi David,

That certainly is a shame.  For the gold plated contact to corrode so badly
means large amounts of potential damage to the flexible PCB.

You may be able to repair it using some brass shim - but I cant see how
else to repair it.

The CX was a wonderful machine - and seeing this has reminded me of many a
night at uni.

Kindest regards,

Doug Jackson

em: d...@doughq.com
ph: 0414 986878

Check out my awesome clocks at www.dougswordclocks.com
Follow my amateur radio adventures at vk1zdj.net

---

Just like an old fashioned letter, this email and any files transmitted
with it should probably be treated as confidential and intended solely for
your own use.

Please note that any interesting spelling is usually my own and may have
been caused by fat thumbs on a tiny tiny keyboard - for this I apologise in
advance - It's ok bec we don* nee* accu tex* to unde** actu**
mean***.

Should any part of this message prove to be useful in the event of the
imminent Zombie Apocalypse then the sender bears no personal, legal, or
moral responsibility for any outcome resulting from its usage unless the
result of said usage is the unlikely defeat of the Zombie Hordes in which
case the sender takes full credit without any theoretical or actual legal
liability. :-)

Be nice to your parents.

Go outside and do something awesome - Draw, paint, walk, Setup a
radio station, go fishing or sailing - just do something that makes you
happy.





On Mon, Apr 20, 2020 at 2:56 AM David Brownlee via cctalk <
cctalk@classiccmp.org> wrote:

> I've come into possession of an HP 41-CX calculator - unfortunately it
> appears to have had batteries left in it which have left corrosion on
> the internal contacts.
>
> (some pics: https://photos.app.goo.gl/48bE7WJZP8R4PF9a9 )
>
> My classic hardware tendencies tend to run more towards the "can run
> *nix" end, and while I could just clean it up and throw it on eBay I
> wondered if anyone here has a 41C shaped soft spot and would be
> interested? (happy to trade/part trade for something they already have
> for which they are less fond if that works :)
>
> David
>