Another dead ste

[philbo34]

Evening.
Following on from other people's issues I thought I would try to resurrect some of my ste s.
Symptoms are no display.
After other people's help, diagnostic cart and tterm
It's showing Rom checksum check fail at cycle 1.
So is checking sockets for connection next step , then substitution.
Or is there something else I should look for first.
Cheers

[DoG]

The normal stuff. Check 5V is good and at each chip is 5V. Try with known good PSU if you have it. Remove chip that is in sockets. Clean sockets and chip with IPA. Use RAM simms that you know is working. Or only try 2 in slot 1 and 3. Try with other ROM chips if you have any.

[derkom]

It's showing Rom checksum check fail at cycle 1.

This may be a red herring. The diag software doesn't know every ROM, and will fail on anything that's modified in any way from Atari original, or newer than the diag software.

[philbo34]

Tbh it's it's tos 2.06 as far as I know .
But all info helps cheers gents

[exxos]

If it's running the test it's half the battle.. But TOS must run a few instructions before the diagnostic cart even boots. Mostly it's down to bad sockets / bent pins etc.

[philbo34]

Got high resistance on some socket pins on hi Rom.
Unfortunately had to go to work