[M100] Fwd: M100 Digest, Vol 115, Issue 24

[B 9]

On Thu, Jul 23, 2020 at 3:35 PM John R. Hogerhuis  wrote:

>
> Otherwise, just pretend like you're Opey Taylor.
>
> -- John.
>

Thanks, John. I had to look up who that was, but I think I understand now.

Bitchin' Model T, Pa!

(or, for those who can't view webp animation: a GIF

)

It's all about hot-rodding our Model-Ts.

—b9

Re: [M100] NDC800 conversion was Re: dual CPU project

[C.Magaret]

I agree, it’s fabulously mind-boggling.  The recent activity alone on this list 
has been inspiring.

CAM

-- 

C.A. Magaret

Sent from my newfangled mobile technogizmo.  Please forgive any typos, 
inelegant brevity, or nonsensical auto-corrections.

> On Jul 24, 2020, at 17:07, Chris Fezzler  wrote:
> 
> 
> My head is spinning with the innovation taking place here the last 10 years.
> 
> On Friday, July 24, 2020, 03:59:21 PM EDT, Stephen Adolph 
>  wrote:
> 
> 
> yah I think so. It is only slightly larger than the 40 pin socket.  should 
> drop it place.
> 
> I can share the mods I made to the M100 ROM.  You might have a hard time to 
> get a working ROM for NEC.
> The reason why is that, on the M100 ROM, I have a patch that creates a BIG 
> HOLE. I found an optimization in how the video code worked, and my patch 
> makes something like 170 bytes free in the ROM.
> I use that hole to embed code to work around the various changes to back out 
> / change the calls that use SIM and RIM.
> 
> (The M100 rom does not make use of the undocumented commands of the 8085.
> 
> So it is a good challenge for you Gary-  Modify the NEC ROM to work with 
> NSC800.
> 
> ..Steve
> 

Re: [M100] CP/M install issue

[tjhoppe]

Thanks everyone! CLEAR 0,6 did it. CP/M now works just in time for the 
weekend.TomSent from my Verizon, Samsung Galaxy smartphone
 Original message From: Philip Avery  Date: 
7/24/20  5:25 PM  (GMT-08:00) To: m...@bitchin100.com Subject: Re: [M100] CP/M 
install issue 
Sorry about that. Have fixed the wiki page. Should be CLEAR 0,6

Philip

On 25/07/2020 11:45 am, Tom Hoppe
  wrote:


  
  I just received my REXCPM module last Wednesday and
got it installed. I was able to get it working with the REX
functionality and that works great, but I'm having an issue when
trying to run the CLEAR command before running CPMUPD.CO
to install CP/M. Even if I start from a clean state with nothing
in RAM (29638 Bytes free) when I run CLEAR I get the following
error:


CLEAR 6
  ?OV Error
  Ok



I'm trying to determine where to go from here. Thanks.


Tom Hoppe


  


  

Re: [M100] CP/M install issue

[Philip Avery]

Sorry about that. Have fixed the wiki page. Should be CLEAR 0,6

Philip

On 25/07/2020 11:45 am, Tom Hoppe wrote:
I just received my REXCPM module last Wednesday and got it installed. 
I was able to get it working with the REX functionality and that works 
great, but I'm having an issue when trying to run the CLEAR command 
before running CPMUPD.CO  to install CP/M. Even if I 
start from a clean state with nothing in RAM (29638 Bytes free) when I 
run CLEAR I get the following error:


CLEAR 6
?OV Error
Ok

I'm trying to determine where to go from here. Thanks.

Tom Hoppe

Re: [M100] CP/M install issue

[Brian Brindle]

Oh for crying out loud...  Put a 0 and a comma in front of what you are
typing and ignore my error laden attempt to type this on a mobile device...

CLEAR 0,6



On Fri, Jul 24, 2020 at 8:06 PM Brian Brindle  wrote:

> Correction, CLEAR 0,6000 - fingers slipped.
>
> On Fri, Jul 24, 2020 at 8:06 PM Brian Brindle  wrote:
>
>> Try CLEAR 0,2
>>
>> Brian
>>
>>
>> On Fri, Jul 24, 2020 at 7:45 PM Tom Hoppe  wrote:
>>
>>> I just received my REXCPM module last Wednesday and got it installed. I
>>> was able to get it working with the REX functionality and that works great,
>>> but I'm having an issue when trying to run the CLEAR command before running
>>> CPMUPD.CO to install CP/M. Even if I start from a clean state with
>>> nothing in RAM (29638 Bytes free) when I run CLEAR I get the following
>>> error:
>>>
>>> CLEAR 6
>>> ?OV Error
>>> Ok
>>>
>>> I'm trying to determine where to go from here. Thanks.
>>>
>>> Tom Hoppe
>>>
>>>

Re: [M100] NDC800 conversion was Re: dual CPU project

[Chris Fezzler]

 My head is spinning with the innovation taking place here the last 10 years.
On Friday, July 24, 2020, 03:59:21 PM EDT, Stephen Adolph 
 wrote:  
 
 yah I think so. It is only slightly larger than the 40 pin socket.  should 
drop it place.
I can share the mods I made to the M100 ROM.  You might have a hard time to get 
a working ROM for NEC.The reason why is that, on the M100 ROM, I have a patch 
that creates a BIG HOLE. I found an optimization in how the video code worked, 
and my patch makes something like 170 bytes free in the ROM.I use that hole to 
embed code to work around the various changes to back out / change the calls 
that use SIM and RIM.
(The M100 rom does not make use of the undocumented commands of the 8085.
So it is a good challenge for you Gary-  Modify the NEC ROM to work with NSC800.
..Steve

On Fri, Jul 24, 2020 at 3:40 PM Gary Weber  wrote:

Great news!

Question for you: I know the dual-CPU board doesn't physically fit
into the socket space in the NEC machines, but would your single
NSC800 adapter fit just fine?

Gary

On Thu, Jul 23, 2020 at 7:38 PM Stephen Adolph  wrote:
>
> Update.
> I have refined my NSC800 aka Z80 conversion for M100 somewhat.
>
> I now have a very simple adapter board that converts the 80c85 socket to 
> accept NSC800.  Small and simple.  Plug and play.
>
> The main rom needs to change to a patched version that I have.  To do so, you 
> need to use one of the various means to convert the strange M100 main rom 
> socket to something more standard.
>
> Why?
>
> Well I am still pushing towards a nice Z80 solution for CP/M.
>
> Besides.. the solution is so clean it is really cool.  Hard to resist!  The 
> M100 could have easily been designed with this processor to begin with.
>
> So why not ;)
>
> My thinking is to offer this as a simple kit or maybe even just release the 
> board.  The BOM is really small.  Processor is easy to get off ebay.
>
> One thing that would be nice, is a new version of tsdos that avoids all the 
> special 80c85 opcodescompatible with 8080.  Then it could run on z80 as 
> well.
>
> Even a patched teeny would be fine I suppose.
>
>
>
>
> On Thursday, July 11, 2019, Stephen Adolph  wrote:
>>
>> Motivated by 2 things
>> 1) discovery of the NSC800 Z80 processor that is 80C85 like
>> 2) continuing to work in the direcition of CP/M
>> 3) and recalling that there are 5MHz 80C85 parts out there..
>>
>> I started to work on a dual CPU card for M100 that enables a couple of 
>> things;
>> - standard 2.5MHz 80C85 operation (default)
>> - switchable clock for 80C85, supporting 5MHz
>> - switchable CPU enabling NSC800 at 2.5 MHz.
>>
>> Board is done and heading to the fab.  VHDL is mostly done.
>>
>> I don't expect this board will be wildly popular but maybe it has some 
>> interest  Double speed M100 seems interesting on it's own, let alone being 
>> able to support Z80 CP/M applications.
>>
>>
>> Any interest?
>>
>> I have purchased material to make 5 of these.
>>
>> A few more comments.
>> - to install this board you need to remove the 80C85.  that's some effort to 
>> do
>> - to run at 5MHz you need to upgrade the 81C55 to a 5MHz version.  That's 
>> also some effort.
>> - NSC800 runs about 5$ on ebay.
>> - fast 80C85 can be had for under 5$.
>> - fast 81C55 can be had for under 5$.
>> - to run at 5MHz  you might also find you need a faster main ROM, and faster 
>> RAM.  TBD on that; will advise after I do some testing.
>>
>>
>>

  

Re: [M100] CP/M install issue

[Brian Brindle]

Correction, CLEAR 0,6000 - fingers slipped.

On Fri, Jul 24, 2020 at 8:06 PM Brian Brindle  wrote:

> Try CLEAR 0,2
>
> Brian
>
>
> On Fri, Jul 24, 2020 at 7:45 PM Tom Hoppe  wrote:
>
>> I just received my REXCPM module last Wednesday and got it installed. I
>> was able to get it working with the REX functionality and that works great,
>> but I'm having an issue when trying to run the CLEAR command before running
>> CPMUPD.CO to install CP/M. Even if I start from a clean state with
>> nothing in RAM (29638 Bytes free) when I run CLEAR I get the following
>> error:
>>
>> CLEAR 6
>> ?OV Error
>> Ok
>>
>> I'm trying to determine where to go from here. Thanks.
>>
>> Tom Hoppe
>>
>>

Re: [M100] CP/M install issue

[Brian Brindle]

Try CLEAR 0,2

Brian


On Fri, Jul 24, 2020 at 7:45 PM Tom Hoppe  wrote:

> I just received my REXCPM module last Wednesday and got it installed. I
> was able to get it working with the REX functionality and that works great,
> but I'm having an issue when trying to run the CLEAR command before running
> CPMUPD.CO to install CP/M. Even if I start from a clean state with
> nothing in RAM (29638 Bytes free) when I run CLEAR I get the following
> error:
>
> CLEAR 6
> ?OV Error
> Ok
>
> I'm trying to determine where to go from here. Thanks.
>
> Tom Hoppe
>
>

[M100] CP/M install issue

[Tom Hoppe]

I just received my REXCPM module last Wednesday and got it installed. I was
able to get it working with the REX functionality and that works great, but
I'm having an issue when trying to run the CLEAR command before running
CPMUPD.CO to install CP/M. Even if I start from a clean state with nothing
in RAM (29638 Bytes free) when I run CLEAR I get the following error:

CLEAR 6
?OV Error
Ok

I'm trying to determine where to go from here. Thanks.

Tom Hoppe

Re: [M100] NDC800 conversion was Re: dual CPU project

[Joshua O'Keefe]

> On Jul 24, 2020, at 12:59 PM, Stephen Adolph  wrote:
>  I have a patch that creates a BIG HOLE my patch makes something like 170 
> bytes free in the ROM.

Can I just take a moment to express appreciation for being in a community where 
170 bytes is a "BIG HOLE?"  Because I love that.

Re: [M100] NDC800 conversion was Re: dual CPU project

[John Gardner]

...I found an optimization in how the video code worked...

Wow.  Good show Steve!  OK,  Gary - Let's see your stuff...   "8)

  ...

Re: [M100] NDC800 conversion was Re: dual CPU project

[Stephen Adolph]

yah I think so. It is only slightly larger than the 40 pin socket.  should
drop it place.

I can share the mods I made to the M100 ROM.  You might have a hard time to
get a working ROM for NEC.
The reason why is that, on the M100 ROM, I have a patch that creates a BIG
HOLE. I found an optimization in how the video code worked, and my patch
makes something like 170 bytes free in the ROM.
I use that hole to embed code to work around the various changes to back
out / change the calls that use SIM and RIM.

(The M100 rom does not make use of the undocumented commands of the 8085.

So it is a good challenge for you Gary-  Modify the NEC ROM to work with
NSC800.

..Steve


On Fri, Jul 24, 2020 at 3:40 PM Gary Weber  wrote:

> Great news!
>
> Question for you: I know the dual-CPU board doesn't physically fit
> into the socket space in the NEC machines, but would your single
> NSC800 adapter fit just fine?
>
> Gary
>
> On Thu, Jul 23, 2020 at 7:38 PM Stephen Adolph 
> wrote:
> >
> > Update.
> > I have refined my NSC800 aka Z80 conversion for M100 somewhat.
> >
> > I now have a very simple adapter board that converts the 80c85 socket to
> accept NSC800.  Small and simple.  Plug and play.
> >
> > The main rom needs to change to a patched version that I have.  To do
> so, you need to use one of the various means to convert the strange M100
> main rom socket to something more standard.
> >
> > Why?
> >
> > Well I am still pushing towards a nice Z80 solution for CP/M.
> >
> > Besides.. the solution is so clean it is really cool.  Hard to resist!
> The M100 could have easily been designed with this processor to begin with.
> >
> > So why not ;)
> >
> > My thinking is to offer this as a simple kit or maybe even just release
> the board.  The BOM is really small.  Processor is easy to get off ebay.
> >
> > One thing that would be nice, is a new version of tsdos that avoids all
> the special 80c85 opcodescompatible with 8080.  Then it could run on
> z80 as well.
> >
> > Even a patched teeny would be fine I suppose.
> >
> >
> >
> >
> > On Thursday, July 11, 2019, Stephen Adolph  wrote:
> >>
> >> Motivated by 2 things
> >> 1) discovery of the NSC800 Z80 processor that is 80C85 like
> >> 2) continuing to work in the direcition of CP/M
> >> 3) and recalling that there are 5MHz 80C85 parts out there..
> >>
> >> I started to work on a dual CPU card for M100 that enables a couple of
> things;
> >> - standard 2.5MHz 80C85 operation (default)
> >> - switchable clock for 80C85, supporting 5MHz
> >> - switchable CPU enabling NSC800 at 2.5 MHz.
> >>
> >> Board is done and heading to the fab.  VHDL is mostly done.
> >>
> >> I don't expect this board will be wildly popular but maybe it has some
> interest  Double speed M100 seems interesting on it's own, let alone being
> able to support Z80 CP/M applications.
> >>
> >>
> >> Any interest?
> >>
> >> I have purchased material to make 5 of these.
> >>
> >> A few more comments.
> >> - to install this board you need to remove the 80C85.  that's some
> effort to do
> >> - to run at 5MHz you need to upgrade the 81C55 to a 5MHz version.
> That's also some effort.
> >> - NSC800 runs about 5$ on ebay.
> >> - fast 80C85 can be had for under 5$.
> >> - fast 81C55 can be had for under 5$.
> >> - to run at 5MHz  you might also find you need a faster main ROM, and
> faster RAM.  TBD on that; will advise after I do some testing.
> >>
> >>
> >>
>

Re: [M100] NDC800 conversion was Re: dual CPU project

[Gary Weber]

Great news!

Question for you: I know the dual-CPU board doesn't physically fit
into the socket space in the NEC machines, but would your single
NSC800 adapter fit just fine?

Gary

On Thu, Jul 23, 2020 at 7:38 PM Stephen Adolph  wrote:
>
> Update.
> I have refined my NSC800 aka Z80 conversion for M100 somewhat.
>
> I now have a very simple adapter board that converts the 80c85 socket to 
> accept NSC800.  Small and simple.  Plug and play.
>
> The main rom needs to change to a patched version that I have.  To do so, you 
> need to use one of the various means to convert the strange M100 main rom 
> socket to something more standard.
>
> Why?
>
> Well I am still pushing towards a nice Z80 solution for CP/M.
>
> Besides.. the solution is so clean it is really cool.  Hard to resist!  The 
> M100 could have easily been designed with this processor to begin with.
>
> So why not ;)
>
> My thinking is to offer this as a simple kit or maybe even just release the 
> board.  The BOM is really small.  Processor is easy to get off ebay.
>
> One thing that would be nice, is a new version of tsdos that avoids all the 
> special 80c85 opcodescompatible with 8080.  Then it could run on z80 as 
> well.
>
> Even a patched teeny would be fine I suppose.
>
>
>
>
> On Thursday, July 11, 2019, Stephen Adolph  wrote:
>>
>> Motivated by 2 things
>> 1) discovery of the NSC800 Z80 processor that is 80C85 like
>> 2) continuing to work in the direcition of CP/M
>> 3) and recalling that there are 5MHz 80C85 parts out there..
>>
>> I started to work on a dual CPU card for M100 that enables a couple of 
>> things;
>> - standard 2.5MHz 80C85 operation (default)
>> - switchable clock for 80C85, supporting 5MHz
>> - switchable CPU enabling NSC800 at 2.5 MHz.
>>
>> Board is done and heading to the fab.  VHDL is mostly done.
>>
>> I don't expect this board will be wildly popular but maybe it has some 
>> interest  Double speed M100 seems interesting on it's own, let alone being 
>> able to support Z80 CP/M applications.
>>
>>
>> Any interest?
>>
>> I have purchased material to make 5 of these.
>>
>> A few more comments.
>> - to install this board you need to remove the 80C85.  that's some effort to 
>> do
>> - to run at 5MHz you need to upgrade the 81C55 to a 5MHz version.  That's 
>> also some effort.
>> - NSC800 runs about 5$ on ebay.
>> - fast 80C85 can be had for under 5$.
>> - fast 81C55 can be had for under 5$.
>> - to run at 5MHz  you might also find you need a faster main ROM, and faster 
>> RAM.  TBD on that; will advise after I do some testing.
>>
>>
>>

Re: [M100] NDC800 conversion was Re: dual CPU project

[Bruce H McIntosh]

On 7/23/20 10:38 PM, Stephen Adolph wrote:

Update.
I have refined my NSC800 aka Z80 conversion for M100 somewhat.


...


One thing that would be nice, is a new version of tsdos that avoids all 
the special 80c85 opcodescompatible with 8080.  Then it could run on 
z80 as well.


Even a patched teeny would be fine I suppose.


It's so cool to see a visionary really sinking his teeth into a project!

A Z80-ified ModelT running CP/M and ZSystem... I just had an 
inspiration: embed something like the um, what was it called, TinyTerm?, 
module inside the case with a video out jack that would let you plug in 
one of those cheap tft displays off eBay to get an 80x24 terminal...


--

Bruce H. McIntosh   bhmcint...@gmail.com   www.afn.org/~scotsman   WA4UF

 Network geek with a strong affinity for Telecasters

Re: [M100] REXCPM working!

[Brian Brindle]

Very impressive! Sounds ridiculous but hunting down an LBR extractor and
dealing with all the old school archive formats has really put me in a
state of nostalgia. Funny thing, when I was younger I used to think self
dissolving archives (SDA) were the most awesome thing on the planet and why
would anyone use anything else? 30+ years later... Oh.. I get it.

lbrate from here works well under linux if anyone is looking:
http://www.svgalib.org/rus/lbrate.html

This is fun!
Brian



On Fri, Jul 24, 2020 at 7:24 AM Stephen Adolph  wrote:

> Awesome.  CP/M action!
>
> On Friday, July 24, 2020, Ron Klein  wrote:
>
>> Got my REXCPM installed and running. It's impressive.  Thanks Steve, Phil
>> and others for making this happen.  Of course, not all SW works well with a
>> 40X 8 screen, but some is configurable.  Any CP/M program that can be
>> configured for a VT52  or Heath-Zenith  H19 terminal has a head start at
>> working. I plan to post some M100 configured CP/M SW in the Club 100 user
>> library when I can.  Starting to remember the DDT commands. Uh oh
>>
>> Ron Klein
>>
>

Re: [M100] REXCPM working!

[Stephen Adolph]

Awesome.  CP/M action!

On Friday, July 24, 2020, Ron Klein  wrote:

> Got my REXCPM installed and running. It's impressive.  Thanks Steve, Phil
> and others for making this happen.  Of course, not all SW works well with a
> 40X 8 screen, but some is configurable.  Any CP/M program that can be
> configured for a VT52  or Heath-Zenith  H19 terminal has a head start at
> working. I plan to post some M100 configured CP/M SW in the Club 100 user
> library when I can.  Starting to remember the DDT commands. Uh oh
>
> Ron Klein
>

Re: [M100] NEC rechargeable battery

[Brian K. White]

What's the condition of the machine itself?  For the one I had picked
up, the screen and keyboard had seen better days...


Same. All kinds of color splash splotches all over stained right into 
the plastic, dull scuffed screen, couple melted spots like from a 
solvent not heat.


But all functional.

The capslock key was stuck originally, but I took the keyboard apart and 
took that particular keyswitch all the way apart and actually got the 
latching mechanism working again just by cleaning lubing and 
reassembling. That's working fine now.


Wrecked the black fiber sheet around the keys while cleaning everything, 
but I actually found the same kind of material at a hobby shop and drew 
up a new stencil using xfig, printed on paper and manually cut out with 
an x-acto knife, and glued a nice new sheet down just like the original.


And all that work is invisible buried under the keycaps in a machine 
that looks ...like it was used in a chemical lab I guess!


I kind of like it now. I like seeing the signs of the history of these 
things when it reflects actual use not just the results of rats and 
weather from being stored under a porch.


--
bkw

Re: [M100] NEC rechargeable battery

[Gary Weber]

> Yeah this particular 8300 was part of a gas chromatography instrument.
> Someone on facebook actually knew about it when I posted a couple pics
> of the weird unknown rom. Now no longer unknown.

Aha!  Yep, I actually acquired one of those same 8300s years ago; it
had that same curly-cord serial cable.  I actually have that very ROM
in my collection, same label with the same version listed.   The 8300
did seem to see a lot of use in industrial applications -- much more
than the 8201A.

> If I install the rechargeable pack, and plug the wall power into the
> battery pack instead of the computer, turn the machine on, and pull the
> wall wart out of the wall, the machine keeps running. The rechargeable
> pack and it's own power jack DO act as a UPS.

That totally makes sense now.   It's that power-disconnect feature of
the main system barrel power jack that they were getting around.

What's the condition of the machine itself?  For the one I had picked
up, the screen and keyboard had seen better days...

Gary

Re: [M100] NEC rechargeable battery

[Brian K. White]

On 7/24/20 1:55 AM, Philip Avery wrote:
A-ha! Thanks Gary. Studying Brian's photos I see that wasn't originally 
a rechargeable pack. My (8201a) pack has the 70K ohm resistor on the 


Yes it was originally a rechargeable pack.

The 5 button-cell original battery is NiCD, and wired right in to the 
wall power jack to be charged whenever there is wall power. The new 
batts are wired exactly the same, I didn't do anything new or different, 
just moved things around physically.


If you're talking about the vestiges of the 4xAA holder shapes in the 
case molding, that is just how they manufactured this pack. They took 
the cad files for the normal case, and just made a small modification to 
create a thin-walled flat spot for the panel-mount barrel connector to 
mount, and didn't bother changing anything else or drawing a new design 
from scratch. I can tell that the case was molded this way rather than 
modified from a normal case. The *design* was modified from the normal case.


I think I took some more pics a few months ago that might show that 
better. I'll see if I can find them.


--
bkw

Re: [M100] NEC rechargeable battery

[Brian K. White]

On 7/24/20 1:37 AM, Gary Weber wrote:

They didn't.  That tiny little battery pack with the external charging
jack was an "aftermarket" thing.  I think it was installed by a
company that did VAR resales of 8300s into industrial label printing
applications.


Yeah this particular 8300 was part of a gas chromatography instrument.
Someone on facebook actually knew about it when I posted a couple pics 
of the weird unknown rom. Now no longer unknown.


https://photos.app.goo.gl/1ZUbWJcqSHpdBFL66

I imagine this must have been pretty much meant to act like a UPS not a 
battery for portable operation.


The capacity or run-time wouldn't be as important as the fact that it's 
always charging and always connected regardless if the wall power is on 
or off.


If I install a normal battery pack with good batteries (robbed from a 
8201a), and plug in a wall power supply into the normal power jack on 
the back of the computer, turn the machine on, and then unplug the wall 
wart from the wall (the barrel plug stays in the computer, simulating a 
power outtage), the computer dies. The normal battery pack and the 
normal power jack do not act as a UPS.


If I install the rechargeable pack, and plug the wall power into the 
battery pack instead of the computer, turn the machine on, and pull the 
wall wart out of the wall, the machine keeps running. The rechargeable 
pack and it's own power jack DO act as a UPS.


--
bkw

Re: [M100] NEC rechargeable battery

[Gary Weber]

> I'll write a program which saves elapsed time & leave the machine on 
> continuously until it turns
> off from low-power. By adjusting charging times, I'll figure out optimum 
> charge-time.

That sounds like a great way to do it, Philip.

> They could have easily used the NEC charging method as it presents 8.4V to 
> pin 5
> of the connector (8201a).

I'm speculating here but the only reason I can think of why they put
together custom rechargeable packs with an external jack would be for
the situation where they would want to have a surplus of extra packs
all being charged separate from the NEC machine itself, and then
they'd use them in the machines when fully recharged.  But, who knows
for sure.

I've refurbished a couple of those weird packs in Brian's photos
myself, soldering in the right 71.5K Ω resistor (hard to find part, by
the way!) and jumper and putting in either NiCad or NiMH cells.  My
favorite is to use five of those small NiMH cells to get a full 6V.

I'll be very curious what you find on the charging times and performance!

Gary


On Thu, Jul 23, 2020 at 10:55 PM Philip Avery  wrote:
>
> A-ha! Thanks Gary. Studying Brian's photos I see that wasn't originally
> a rechargeable pack. My (8201a) pack has the 70K ohm resistor on the
> "set" lines & Ni is bridged to positive. They could have easily used the
> NEC charging method as it presents 8.4V to pin 5 of the connector (8201a).
>
> Slow charging Ni-MH is a black art so I figured I'll do some experiments
> to see how long it takes to fully recharge. I'll write a program which
> saves elapsed time & leave the machine on continuously until it turns
> off from low-power. By adjusting charging times, I'll figure out optimum
> charge-time.
>
> Philip
>
> On 24/07/2020 5:37 pm, Gary Weber wrote:
> > They didn't.  That tiny little battery pack with the external charging
> > jack was an "aftermarket" thing.  I think it was installed by a
> > company that did VAR resales of 8300s into industrial label printing
> > applications.
> >
> > By the way the 5-cell NiMH solution works really nice.  Keeps the
> > voltage way up in the acceptable range throughout the discharge cycle.
> > I definitely recommend the solution Brian highlighted.
> >
> > On Thu, Jul 23, 2020 at 10:32 PM Philip Avery  wrote:
> >> Why did NEC go with such a small battery for the PC-8300?
> >>
> >> I've just rebuilt my PC-8201a pack and it had 4 x AA Ni-Cd's originally. I 
> >> replaced these with 4 x Eneloop AA's (2000mAh) & lowered the charging 
> >> resistor value so it will charge them in a reasonable time-frame, ie 
> >> overnight.
> >>
> >> Philip
> >>
> >> On 24/07/2020 3:40 pm, Gary Weber wrote:
> >>
> >> Brian,
> >>
> >> Those are precisely the same batteries I've been using to build up 
> >> refurbished 5-cell rechargeable packs for my machines also.  They've been 
> >> working very well.
> >> I got my battery sets off of eBay and they arrived within 10 days or so.  
> >> They still sell them there so you'll be able to find 'em.
> >>
> >> Gary
> >>
> >>
> >>
> >>
> >> On Thu, Jul 23, 2020 at 8:34 PM Brian K. White  
> >> wrote:
> >>> My PC-8300 came with a rechargeable battery pack that had a tiny 60mah
> >>> battery originally, a 5 button cell nicd hot-glued in the middle, with a
> >>> couple diodes & a resistor and it's own barrel jack to charge the pack.
> >>> All corroded and dead of course.
> >>>
> >>> I determined that you could fit 5 x 1/2AA nimh cells in the same case,
> >>> same voltage, same charger, and get 800mah instead of 60.
> >>>
> >>> 1/2AA is a size that exists, but is pretty hard to find.
> >>>
> >>> I found this on Amazon, welded tabs already, and even sold in sets of 5,
> >>> exactly the number needed, perfect.
> >>> http://amazon.com/gp/product/B07ZNZ535F/
> >>>
> >>> Not so perfect, it took over 4 months to arrive (March 17 to July 21).
> >>>
> >>> But they did finally arrive, and the size worked out.
> >>>
> >>> Everything fits, and it's easy to replicate the original wiring just
> >>> moved around.
> >>>
> >>> https://photos.app.goo.gl/JRVp71Govw49PXaM6
> >>>
> >>> --
> >>> bkw
> >>
>