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
> >>
>

Re: [M100] NEC rechargeable battery

[Philip Avery]

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

Re: [M100] NEC rechargeable battery

[Gary Weber]

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
>
>

Re: [M100] NEC rechargeable battery

[Philip Avery]

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

Re: [M100] NEC rechargeable battery

[Gary Weber]

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
>

[M100] NEC rechargeable battery

[Brian K. White]

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