开云体育

Hi,
I've been a long time lurker is this group, recently I had some time to look at
a 7A42 that bought a few years ago. Like others I have the leaky NiCd issue.
I've neutralised the leakage with vinegar, cleaned up the board, fixed some tracks,
and replaced two corroded diodes associated with the battery circuit.

Running the 7A42 without a new battery, it completed the self-test but then
I started to see some erratic operation in front panel LEDs, relays and on screen text.

Has anyone seen this?

My first thought was one of the EPROMS my be faulty. Some of the time however
the self-test starts again, and prior to installing a new battery I found that the battery
negative connection is not connected to ground so I suspect there is some corrosion
at this point on the board and possibly there is intermittent shorting between the internal
+5V and ground layers.

Does anyone have any thoughts on this?

Regards,
Peter

Further to the issue I described in my last post, I installed a new battery and the erratic operation has not occurred.
I still have to few tests to do but I now suspect that the battery charger isn't working as this also supplies power
to the RAM chips even with no battery installed, so with no supply to RAM this could be the cause of the erratic operation.

Regards,
Peter