a4000 wierd memory problem : help!

[Castellen]

There are 3 PCB tracks that run right through the real time clock area which often get corroded open circuit and can cause memory problems.
Look at the underside of the modtherboard, at the beack end of the U850 SIMM slot, and you can see there are 3 tracks running to 3 vias which are right beside the RTC battery, but under the edge of the SIMM socket.

Use a multimeter to test the integrity of the tracks from the SIMM slot to their destination.  They run to vias beside U216, so it's enough just to test them to that point.

Don't forget to clean the edge connectors on the SIMMs and the pins in the sockets using isopropyl alcohol to make sure there isn't a poor connection caused by dirt/grease.


Information on RTC battery replacement:
http://amiga.serveftp.net/Battery.html

And RTC fault finding/repair:
http://amiga.serveftp.net/RTCrepair.html

[Castellen]

Well New Zealand is closer to you than Perth, so I'm almost within the Melbourne area :-P

If you can't find anyone else, I do component level motherboard repairs and PCB track repairs.