HP54815a infiniium repair

[meriororen]

Hi,
Hello from Japan. There're plenty of old electronics here that can be picked up from japanese "eBay", the Yahoo Auction Japan.

Recently I bought an old HP 54815a, no probe for about $150. It doesn't boot, only brings me to that old AMI boot display then it
says "Battery Low" and gives me 2 choices: F1 to do bios setup, F2 to load defaults.

So I did the BIOS setup (the setup is WINBIOS, with GUI! I can use mouse),
looking at the manual (just basic one from keysight website), I set :
- clock
- IDE controller to be primary (this one is disabled by default)
and do save and exit.

However, when it boot again, the "Battery Low" is still there, entered the setup again, and saw that
- clock setting is retained from the previous setup
- IDE controller is back at disabled!!

I checked the battery, and it still has 3.2v in it, just to be sure, I bought a new battery, this one has
cr2354 battery with seat, so I had to desolder it to replace a new one. The original one is Panasonic cr2354/GUN
I couldn't find that here in Japan, so I bought similar replacement that is cr2354/GUFK. checked
it has 3.2v and soldered it in.

The problem persisted. It still says "Battery low".

I am guessing the problem is in the bios memory itself (hopefully not the mobo). However I am not really sure
because the clock setting is ok.
The bios memory is a combination of volatile cmos sram (sony cxk58257cm-70ll) with dallas ds1210s nvram controller.

So now I am waiting for replacement ds1210 and sram (I couldn't find cxk58257cm anywehere, so I am ordering cxk58257am,
hopefully it's the same)

Anyone have thoughts on this?


 

[meriororen]

OK, quick update.

I was looking at wrong battery all the time..

That was probably backup battery for calibration data, since it's on IO Board! Silly me. 

The correct battery is a Dallas DS12887A, basically integrated RTC + NVRAM + battery. It's easy to rework this chip apparently if I googled it down a bit..

http://www.mcamafia.de/mcapage0/dsrework.htm

So there it is, it boots up perfectly! 4th channel seems dead tho..