Low-rent Battery Replacement

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More fiddling with decrepit hardware that should just he snuck into the
dumpster behind Denny's:

DX2 66MHz machine that may well work, but I cannot get output from the
onboard video--three beeps.  I don't have and ISA video card to try, but
suspect there is at least one other barrier in the way: the battery.

A Varta 3.6V 60mAh cell was soldered on the board.  It looks a bit oozy
and cannot offer more than a half a volt.  I'm going to try the system
without any battery, and probably with a couple of AAAs in serial, but I
have my doubts.

Any ideas as to how I can reasonably and cheaply approximate the
original cell?

- - - - - - - - -

Just a blast from the past for you guys:

1) It's an Epson PC running a custom Epson motherboard.

2) It has a Connor hard drive.

3) It has a 2x Mitsumi optical drive.

4) It uses an ISA riser card.

5) Power supply is a tiny smart-mouthed bird on a treadmill.

Re: Low-rent Battery Replacement

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First off...a dead cmos battery generally will not prevent a machine from

The beeps may be due to ram problems...

try it with just two sticks in different combinations...

If you do manage to get it working... three aaa's in series will do the

Re: Low-rent Battery Replacement

philo wrote:
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Yeah, tried that.  There are two sticks, two slots, so I tried all 6

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Re: Low-rent Battery Replacement

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Well if you can scrounge up some RAM somewhere I'd probably try some a few
different sticks.

Don't really know what the bios codes mean...but most bios code beeps are to
do with either RAM or Video

If you are in the US and *really* want to try to get the thing going

send me a line   (my gmail addy is philo565)

I've got pleny of old RAM and ISA video cards that I sure as heck don't need

Re: Low-rent Battery Replacement

philo wrote:
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Thanks. I think I'll just tinker. There's an adjacent charitable
organization that has received this PC as a donation. I sometimes clean
up their system, make sure any personal data is destroyed, replace minor
broken bits, and make up a "features" list for the unit.

I'll rate the system from 10 (near to current mid-range system) down to
a 0 (only suitable for parts.)  This system, if I can get it working,
will be rated a 1 (museum ready).

Re: Low-rent Battery Replacement

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are to

I cannot pass up any discarded computer .

If it's any decent at all...I fix it up and bring it in to where I do
volunteer work.

Once in a while I'll save one for my collection...but keep my own museum
down to an absolute minimum.

I recently gave away a server that weighed at least 100 pounds.

I told the guy that I managed to get it down there...
but he'd have to get it out of there without my help...
He picked it up and put it in his van...then asked if I had any more!

I gave him a slightly smaller one and finally was able to walk through my
basement <G>

Nowdays...the 486's just go to the computer recycler as I seem to be able to
find p-III's and P-IV's being tossed out!

Re: Low-rent Battery Replacement

On Wed, 16 Jan 2008 22:09:54 GMT, Grinder

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How cheaply?  
Are you willing to desolder and resolder?
Is there an add-on battery pack pin header?  I vaguely
recall (but would be more comfortable with you using a
multimeter to make sure) there might be a pin header near it
with a jumper across two of the pins.  If there is you might
try taking that jumper off (remembering where it was) to see
if that disconnects the battery from the board.

One option for the battery is a typical cordless phone, 3.6V
NiCd battery pack.  Of course you'd have to mount it
externally, but for the time being if you just soldered a
couple wires to the board you could plug them into such a
battery pack if you happened to have one already so you'd
know if the board can be coaxed into working before spending
money on a battery for it.  If the battery pack had a
connector compatible with an existing battery pack pin
header on the board, so much the better.

In the interim, if the jumper I mentioned above isn't there
or it's removal doesn't help, I'd just clip off the original
battery as high up on the pins as possible (so you still
have some pin to grab from the front while desoldering from
the back).  With the battery off, try it again... could be
the battery is shorting out.

As for the rest, is the system otherwise in the original
configuration or have you added parts?  I'd tackle the
battery first but if that doesn't help, it seems quite
possible it was thrown out due to failure and since systems
of that era weren't particularly susceptible to capacitor
failure I'd suspect general dirt or corrosion of contacts or
power supply failure.  That is, unless someone has already
tried to *fix* it and then there's no telling what has been
changed from it's original configuration like jumpers.

I have to wonder if it's really worth getting working.  Even
if it posts there may be several other things wrong like
unreading optical drive, bad sectors on hard drive.

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Has the bird been fed recently?  Does it seem friendly?
It might be the problem, probe it with a meter.

Re: Low-rent Battery Replacement

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Are there leads from the battery that you could snip?  If so, you
could cut out the battery and then solder on wires to one of those
square packs that has a velco strip to keep it in place inside:


Or you could get the 3-button battery blister:


(Never bought from this store.  Found it using Froogle and searching
on "CMOS battery 3.6V".)

Re: Low-rent Battery Replacement

Grinder wrote:
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If you substitute alkaline or other non-rechargeable cells for the
original soldered-in battery, be sure to either put a diode in series
with them  (schottky may be best, or use 3 alkalines) or deactivate
the charging circuit built into the motherboard.  That circuit may
consist of a diode and resistor, and you may have to remove either of
those or cut a soldered jumper wire.  There may be 2 diodes, one for
the charging circuit, another to steer the battery's output current.

Some older motherboards have a jumper to select between onboard and
external battery, in which case all you have to do is switch the
jumper and plug your alkalines into a pin header in the jumper's

I had one motherboard that would do nothing but beep if there was no
battery in place.

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