A4000 fastram address error

[pentivarg]

Hi,
I wonder if anyone has an idea of what hardware error can generate this error message (please see attached image). And where on the motherboard I should do more thorough checks.
I have several ram-modules, all 4 MB 70 ns. The jumper on the motherboard is set at 4 MB modules.
It doesn’t matter which module I use, or in which slot I put them, I still get the same error as in the image. If I change slot the only thing that change is the address range tested.
I’m using DiagROM v1.3. The CPU is a 68040 on a A3640 rev 3.1 board. The A4000 motherboard is rev B.   
I would be most grateful for any input that can help narrowing this down to something that can be fixed 😊
Stefan

[pentivarg]

I should have mentioned that. It has recently been recapped. The battery has been replaced by a new one. The area around the battery looks quite good. Nothing visual that looks wrong. I don't think the old battery leaked. I have another rev B MB which had some serious battery leakage so I know how that looks like.
But yes, it could still be a small trace damage somewhere. The question is in which area of the MB to start looking.

[pentivarg]

Thank you for your very detailed instructions I do have a PicoScope 5243D MSO but to be honest I have never used it I'm a semi-noob at this but I got a genuine interest to learn how to triage at that level.

If I only have chipram installed everything is fine. It boots up and the diagrom happily runs the chipram tests, including address error checks.
If I boot from normal kickstart with fastram installed the power led blinks and the screen stays black. I'm using a RGB to HDMI converter so the colors are not accurate and it lags a bit when the input signal comes and goes.
It's only when I use diagrom that I can get it to boot with fastram installed.

Are there any other tests I can run to narrow it down before bringing out the big guns (the oscilloscope) which I'm not 100% sure how to use yet... Haha

[pentivarg]

I have run the diagrom address range test which is what is shown in the screenshot in the first message. I have also moved around the simms between the sockets with the same results.
But I have not tested to replace the super buster. I have one on another motherboard so I can try using that one and see if I get different result.

[pentivarg]

I have a spare (heavily corroded) rev B MB with a Super Buster 390539-11 on (same as on the MB I have problems with), I will try that one and see if I get a different result from DiagRom 1.3.
Thanks