exxos's Atari, Amiga & retro forum

I personally would make the assumption you have a bad connection on your CPU socket somewhere. I suggest you go back to square one and start continuity checking every pin on the CPU to things like the MMU & GLUE etc.

ok.. god knows that has had a lot going in and out in the last couple of years.. so that could be it.

but if it starts working, and goes bad.. how do I find the bad connection.. if the connection is good when cold?

James

While testing continuity push various places on the board about a bit..

exxos wrote: 29 Oct 2021 21:11 While testing continuity push various places on the board about a bit..

Well no luck with that.. everything checked out ok, from CPU to all points I could find. pushed the board, but did not flex it hard or anything.

I guess I will try some memory chip substitution. I can put things together and take them apart, but my logic troubleshooting is not there. Might be an easy fix, but I am not aware how to trace it down.

James

Before you do that, seeing as it changes with time, and hence heat, use a freeze spray to see if you can localise the problem. You don't want to create more faults whilst diagnosing the first.

stephen_usher wrote: 30 Oct 2021 14:55 Before you do that, seeing as it changes with time, and hence heat, use a freeze spray to see if you can localise the problem. You don't want to create more faults whilst diagnosing the first.

Could you be more specific Stephen?? can of compressed air??? and where would you suggest I spray??

james

Well, some air cans can work as freezer sprays by turning them upside down. These are usually the flammable ones.

Where to freeze? anywhere where the data bus goes. Try the CPU area, MMU, RAM just to see if spraying any chips (or area of the motherboard) makes a difference to the behaviour.

stephen_usher wrote: 30 Oct 2021 22:32 Well, some air cans can work as freezer sprays by turning them upside down. These are usually the flammable ones.

Where to freeze? anywhere where the data bus goes. Try the CPU area, MMU, RAM just to see if spraying any chips (or area of the motherboard) makes a difference to the behaviour.

So I have never done the spray before Stephen, I have some now.. am I starting up the machine and spraying an area before things go bad? after they go funky? before I turn it on??

Wait until it heats up to go bad.. turn it off.. spray.. and try again??

James

Leave the machine on, and when it starts failing, then spray select locations on the board and see if the fault disappears.

I would advise keeping it away from the power supply as some sprays can be highly flammable.

exxos wrote: 02 Nov 2021 14:43 Leave the machine on, and when it starts failing, then spray select locations on the board and see if the fault disappears.

I would advise keeping it away from the power supply as some sprays can be highly flammable.

thanks exxos, this one does say non flammable.. I was always under the impression extreme cold hurt electronics as well.. I am guessing just a little blast should give me results.

So, start at the CPU I am guessing because we thought originally issues might have started there??

James