Dead Batteries again

[TjLaZer]

Ok I just got two A4000s and one A2000 from eBay.  Got a great deal too.  All 3 have dead batteries.  On the 2000 the battery has leaked pretty good on the MB.  I removed the batt.  Whats a good way to clean the MB?  On the 4000s one was fuzzy white and the other was starting to fuzz but looked ok.  I removed the fuzzy one and no leakage from what I can tell.  On the other one where the batt looks ok it seems to allow me to change date but does not keep date.  This indicate a dead battery right?  On one the save was grayed out, what does that mean?  Dead batt or batt not present?  Just confused on the ways a battery would be considered not working.  Should I go ahead and yank the batt out of this one too?  Any info would be great.

[voxel]

Yes, you have to remove all that three old dead batteries and put some nice new ones, after cleaning somehow the MB.

[Castellen]

Yes, if the battery shows any sign of corrosion, or has not been replaced recently, then replace it immediately.

All the information you need is here:
http://amiga.serveftp.net

Look in the battery replacement section.


The greyed out save option means the system cannot see the real time clock.  Refer to the RTC repair section (linked off the battery replacement page).

[TjLaZer]

Great site thanks, the question I have is: if a battery is removed, will the save still be ghosted in prefs/time setting?  The site seems to say if it is grayed out there is damage to the RTC circuit.  It says to test it before installing the new battery which is confusing as how can it be present with out a battery to be able to save to?

[Castellen]

Yes, the save will still be ghosted regardless if the battery is there or not.
The system checks to see if it can read from the RTC, and if it can't (probably due to corroded tracks) then it ghosts the save button.

When it's working, you can still save to the RTC even if no battery is fitted.  The RTC will store the time and date until the computer is physically powered off.
In other words, with no battery fitted but the RTC is working, you can save the time, reset the computer, and the time will be kept.

[TjLaZer]

Ok you are correct. On my A2000 which had a really bad corroded battery, I removed it and cleaned it and it seems to work ok.  Not batt and Save is present!  Go figure, on my 4000 which had mild corrosion, a track must of got ruined, as save is ghosted.  Well I will look into seeing if I can fix the 4000.  I do see a slight discoloration of a track near the batt location and nearby chip.  Maybe this is the one that was damaged...

[Castellen]

Thanks, I'd hope I was correct, it's my job to know :-P

As mentioned before, the battery is only required to make the RTC store the date/time information when the power is off.  If the system is turned on, the RTC is powered from the power supply, and the battery charges up at the same time.

Even if the PCB tracks appear to look clean, it's still possible one could be open circuit due to corrosion.  This usually happens in or right beside vias (the holes joining tracks between PCB layers).

It's also common for corrosion to damage U177, the RTC data latch.

My website, mentioned before, has all the information you need to fix the RTC, look in the RTC repair section and follow it through step by step.