@Greenfield

Hello there, it does indeed sounds like your A4000 is a little poorly.

Sadly I am sure to suspect that your on-board battery has leaked - as such it has caused damage to your A4000 Motherboard.

With the symptoms you have described I am sure that a couple of IC's will need to be replaced as well as some capacitors - not to mention the removal of the battery and motherboard clean up.

At this juncture I would suggest you open your A4000 and remove (gently) the Battery - from this I would use some lemon juice on the motherboard - be liberal - and let it rest for about 10 minutes - again gently - with a toothbrush have at the motherboard (primary area will be the side of the Battery - but get as much as you can.

Once you have done this I would recommend IPA (Isopropyl Alcohol) and be liberal when you apply this to the motherboard - gently work this in and then give it 30 minutes dry time.  

Make sure the rest of the board is dry.


Now, this WONT repair the problems but it will ensure that it doesn't get any worse.  The motherboard will need some serious repair at this stage - it will require SMD reworking - soldering skills.  

do you know anyone local in your area ?

If not you could ask here, there are also members whom offer repair services on www.amibay.com


I hope that helps.

and that's not the complicated part(s).
Does you machine still show the correct amount of RAM on the Workbench screen? If I remember right, the chip RAM is usually affected first.
After cleaning, start checking traces, SIMM sockets and chips. But by all means get that battery out of there, and clean it! Today!

The fast memory can be affected if U891 (part of the fast memory data bridge) becomes corroded, which is fairly common as it is right beside the RTC battery.  The outer fast memory SIMM sockets, tracks and SIMMs themselves can become corroded causing further fast memory issues.  It's less common for the chip memory to be influenced as the SIMM and the interfacing components are further away from the typical corrosion affected areas.

But yes, remove the battery first, then replace all of the corroded bits and repair the damaged tracks/vias.

I've written repair guides on it here and here.  If you can't find anyone local to fix it, then I'm happy to have a look in November when I'm back in the real world.

Well, I think it's been like that for years to be fair and it's not got worse in that time. Chip RAM is 2Mb, other ram is 14Mb (total of 16Mb I think). I will be opening the case soon to take some pics.

Believe me when I say, it will got worse in that time. It may not have any more symptoms, but these things only get worse, never better.

Get rid of that battery before it's completely toasted the A4000!