On 1/13/22 21:36, Alex // nytpu wrote:
Hi all,
A NEC PC-8201A I picked up just arrived, and I have a few questions,
particularly on the internal battery.
It arrived and didn't boot with fresh alkaline batteries, so I opened it
up. The internal NiCd battery was starting to corrode so I removed it
(lucky I caught it now before there was a disaster). Everything else
looked perfect internally so I closed it back up and tried booting it
again, and it worked perfectly! It's obviously not an issue but I was
just wondering if anyone had that happen---it's strange to me that a
dead battery being present doesn't boot at all while no battery at all
works fine.
Perfectly expected. The dead battery is pulling the vcc rail down.
If you left the unit plugged in to the wall for about a day, it *might*
have brought the battery back up enough to allow booting, though it
would still be an old battery with no capacity and starting to leak. You
still needed to replace it regardless so no loss.
On replacing the internal battery, according to this email[a] from
November both ArcadeShopper and Soigeneris had replacement batteries,
however looking now neither of them have any in stock. Does anyone know
if they're going to get any more in? I don't mind waiting if it'll just
be a while but if they aren't planning on ever getting them back I'll
look around elsewhere for one.
For alternatives, since the internal battery seems to be recharged from
the main battery pack I assume a regular CR2032 would be a no-go, but
has anyone tried out soldering in a socket + LIR2032?
Without some hacking, you can't use anything else, just nicd or nimh,
3.6v (3 cell), and even with the correct battery, you can't leave it
plugged in more than about a day, 2 at the most. More than that and
you're cooking the battery off. The charging circuit is very crude, no
intelligent battery management, doesn't cut itself off, etc.
You can use larger or smaller capacities if you wanted to deal with
rigging up your own physical mounting and running wires, as long as they
were the same chemistry and voltage. So for instance you could use a
much larger 3xAA cell pack, as long as it's 3 nicd or nimh cells for the
same 3.6v and the same nicd or nimh chemistry, but you'd have to find
some other place to mount it and run wires.
You could use something totally different only if you include a diode to
prevent the charging circuit from being able to charge the battery, but
a cr2032 would die fast.
For a replacement battery, google "3v80h 2pin nimh"
You'll still get a lot of 3-pins in the results so pay attention to only
look for the 2-pin ones. There will also be a lot of questionable ones
on ebay that I would be careful about. Some will be good but some will
be junk that looks good but leaks after a year or it's reject or old
stock that should have been thrown out etc.
This is a good one.
https://www.batterystore.com/3-v80h-2p-55608-303-015/
Particularly, the wire tab that this one has is a bit specially
recommended for 8201 because there is a trace on the pcb that runs very
close to the + pin.
There is another common battery tab style with flat sheet tabs that can
short that trace, and the wire type above is better than for example
this type: https://www.batterymart.com/p-3_6v-80m-2-pin-nimh-battery.html
I recommend squirting a little bob of hot-glue under the battery to hold
it and provide strain relief for the solder joints.
--
bkw
