Optiplex GX620 will not remember bios settings

Which version of the GX620?  There are four different versions.

First, the obvious.  Make sure the replacement battery is good and second make sure you are installing the battery with the correct polarity.

However, in reference to the Dell manual, it would appear there is some type of motherboard problem.  In most Dell's, if there is a BIOS problem or corruption, the ONLY alternative is to replace the motherboard.  

From the manual:

"Replace the battery  —  If you have to repeatedly reset time and date information after turning on the computer, or if an incorrect time or date displays during start-up, replace the battery. If the battery still does not work properly, contact Dell."

Thank you.  The battery is new, and it was easy to install, and I did look in the manual about the proper polarity.  Of course, you can tell by looking at the battery socket which way the battery must go.  I suspected it was a motherboard problem, but what I had hoped was that someone who had already solved a similar problem would tell me what exactly is wrong with the motherboard.  Is it the battery socket or a capacitor?  I see from doing some research that this problem is not necessarily unique but I am sure that a number of different factors could possibly cause it.  Thank you again for your reply.

And I meant to also mention that contacting Dell does not seem to be possible.  This forum is the only means I have of getting support.  I bought the computer 2nd hand, so I do not have the account information to go with my service tag, which is required before any Dell person will speak to me.  Believe me, I've tried.

I forgot to answer your question on the "version" of GX620.  This is the Mini-Tower.  The motherboard is labeled HH807.  My CMOS battery is brand new and there is nothing wrong with it.  This appears to be a motherboard problem of some kind, as it could hardly be anything else at this point.  Surely, someone else has seen this before.  I'm sure Dell knows what the problem is.  I can fix it myself if someone would give me a hint.

The BIOS is not corrupted, since once I reset the date/time, the system boots up just fine and runs normally.  I've seen other forums talking about capacitors going bad in the small form factor versions of the GX620, but I can see no evidence of this here.  But I am capable of replacing the capacitors.  I am sure that Dell would say that the ONLY alternative is to replace the motherboard, but that is the ONLY alternative only because that is the only one they offer.

Thanks for replying to my post anyway. 

We recently had another forum member with a similar problem, but on a different PC model. It turned out the "new" battery, straight from the store and in a sealed packet, was as dead as the old one.  Another new battery solved his problem. So just because you recently purchased it, doesn't necessarily guarantee it's fresh. :emotion-5:

You can try this. Power off and unplug. Press/hold power button for ~15 sec. Open the case and remove the battery. Press/hold the power button again for ~30 sec and leave it that way for a while. Then Install a 'good' battery and try again.

And if none of that fixes it, then possibly the voltage sensor on the motherboard has failed...

Ron

Thanks Ron.  It's a good battery.  It tests at 3.2v.  The old battery that I took out tested at 2.9v, and I suppose that in use, the voltage might have been drawn down even more by whatever load it has on it.  But I seriously doubt that it takes much current to maintain the CMOS memory.  By the same token, it probably doesn't take much of a component drift to put it out of whack.

It is interesting that I do not get any messages logged at the BIOS for "CMOS battery voltage low".  When the battery is installed, the motherboard seems to know that it's voltage is appropriate.  It's only when I unplug the machine for a minute or more that the problem appears.  And just for fun, I tried to boot up the machine with no CMOS battery at all, and although I was sent to the BIOS to reset the date/time, after doing so, the machine posted a message that it needed a battery.

I've seen motherboard replacements that aren't too expensive.  However, it just gnaws at me to not know what is wrong with this one.  $60 more spent on a replacement that either has the same problem or soon develops the same problem will not make me happy.  So I am in the process of replacing all the capacitors on this motherboard.  I'm doing this in stages, and the first stage was unsuccessful... but so far, I've not made matters worse.  If I am going to have to replace this thing ultimately, I might as well try to find the bad component.

Is there something else you can tell me about "the voltage sensor"?  Because, to me, this doesn't appear to be related to the power supply in any way.  There is a circuit dedicated to CMOS battery itself that is most likely the culprit.  If I had a schematic, I'd be in much better shape.  Of course, if the bad component is one of those ultra-tiny things on the board, I will gladly give up.  I've tried before to replace one of those, and it is nearly impossible.

Thanks again

As long as the motherboard is receiving power (eg, when the motherboard LED is on), it holds BIOS settings even if the battery is dead. But when you unplug, it loses the settings either because the battery is bad or the battery circuitry has failled.  I never get the low battery warning on my 8400. After ~2-3 years, the battery abruptly dies and the system won't boot until I replace it.

Seems to me like a lot of time, effort and pain to match and replace all the caps on a motherboard. Dell doesn't provide schematics so you're on your own.

Ron

How does the battery circuitry fail?

I appreciate your continued interest in my situation.  However, this battery is not dead.  There just isn't any reason to keep implying that it might be.  I have three other PCs currently, and have had them for many years.  They are no-name machines put together with custom parts.  I have never... ever... had a problem with a CMOS battery, and I do loose power in the house from time to time.  These batteries can last for more than 10 years, not 2-3 years.  I have had a dusty old computer unplugged for months, and it boots up with the CMOS memory intact when I've decided to hook it up again.  This is a Dell problem, or to be fair, it is a Dell problem that Intel, most likely, is responsible for... whoever it was that made this motherboard.

And you are correct about that last thing.  It IS and has been a lot of pain and effort to attempt to replace these capacitors, and not really worth the effort if all I needed was for this computer to work.  I don't really need it to work as much as I want to know what's wrong with it, if that makes any sense.  And I am not surprised that Dell does not provide schematics. They don't provide customer service to 2nd hand computer owners either.  They will make you think they are going to help you, transfer you to a number that nobody answers, or just disconnect you.  They DO provide this forum, which I think is great.  If I figure this out, I will post the solution.

Thanks.

this is probably a shot in the dark but most motherboards have a set of jumper pins that will reset bios therer are three pins in normal use pins 1 & 2 are jumped to reset bios jump pins 2 & 3 is it posible that the previous owner did this and did switch back you might be able to look up your motherboard online to see if it has this jumper

good luck

Thanks, but I checked that already.  On this particular motherboard, you move the jumper from the 'password enable' to the 'bios reset' to accomplish that, and the jumper is not on the 'bios reset'.