Bally Alpha NVRAM Battery 2 Constantly Dies, Errors.

[Ash100]

I've got an Alpha M9000 that I'm having Battery problems with.

The NVRAM Battery #2 only lasts a couple of weeks before it dies.

I'm not sure where the added current draw could be from at this point.

I've changed out the MPU 3 times, same problem,  so I don't think it's related to that. So, what's on the Backplane that draws current from the MPU Batteries?

Surely I don't have 3 bad MPUs doing the same thing.

I've even tried different brands of Batteries with plenty of shelf life left in them. No difference.

Or, could it be a BIOS EPROM or Jurisdiction Chip causing the issue? Those are the only things reused in each situation.

Kinda stumped on this one.

Thanks,

Curtis ash100

[Ash100]

Anyone?

Curtis ash100

[lookes]

Looking at the schematic it appears that battery2 does connect to the backplane through a 2.2K ohm resistor. I don't have a schematic for the backplane to see where it goes or what it does tho. If there was a short to ground on the motherboard you would drain the battery to 2V in about 7 days.

Try leaving the MPU out for the two weeks and see if the battery drains. That would narrow it down.

[Ash100]

Thanks John,

That's a great place to start.

I appreciate the reply and will let you know how it goes.

Curtis ash100

[rickhunter]

Did you ever figure out your battery drain issue?

[Ash100]

I changed the Battery and programmed it last week.

I'm going to give it another week with it being unplugged from the Backplane and see what it does when I plug it back in and fire it up.

I put in a WTB for a Backplane, but haven't received any replies yet. The M's are shorter and wired differently than the S9000 Backplanes.  Hopefully that's all the problem is, but won't help me any if I can't find a replacement Backplane.

I'll repost with an update once tested.

Curtis ash100

[Ash100]

Latest Update....

That did not work.

I left it separated from the Backplane for over 2 weeks, pushed it in and Booted Up.

Halted at NVRAM Battery #2 Low.

So, what's next?

I'll try a different MPU when I get time to mess with it again.

Curtis ash100

[lookes]

Try a new MPU altho it seems you have already isolated it to the MPU. I can probably find the cause of the drain if you determine that it is the MPU.

[Ash100]

Update to the NVRAM Battery #2 dead after 3 days.

After a lot of parts swapping and trial and error, I was able to scrape together 2 complete MPUs with working Video etc.

I completely assembled 1 with BIOS, SJUR, Power Supply and Fans (original configuration) and the second with just the MPU Board and Video Card.

The one with just the Video Card, or Adastra, or whatever its called with the large Heat Sink was left on the bench for a week or so and had a completely drained #2 Battery.  So, it is in that Board or the mess beneath the Heat Sink.

The second one completely assembled, to rule out BIOS, SJUR and PS Drains held a charge on both Batteries for the same length of time. 

The next step will be to install that MPU into the Machine, configure it and see how long it lasts.

More to come.

Curtis ash100