How would I go about metering the rom lines back to the CPU? The service manual available for the ST suggests that a failure of RAM is what will produce that dark red screen at power on. I need to get a hold of a diagnostic cartridge or remove your RAM board and put in a bank of dram. I knew I shoul...

Another update. Carefully removed the 2 old 28 pin TOS sockets and soldered in EXXOS Dual Bank ROM board and I think its in 1.04 TOS mode and the board is in GLUE mode so it should POST okay but NO CHANGE with either original CPU or the 2.3 booster in the tested CPU socket on my SM124. I then stupid...

Just a brief update. I resoldered all of the 4mb board joints. No change. I then as Exxos suggested looked at the TOS Rom sockets. I had nothing to lose so I reheated and applied solder to the 2 x 28pins of both of the ROM sockets. Interestingly No change initially but during ONE of my reset button ...

Just tried 3 different cpus. No change however if I damaged the new cpu socket I would be very surprised. I also waited 30 seconds on my mono monitor too see if there were any diagnostic beeps or border flashes but still nothing. Tried swapping floppies as I have a spare from the GOTEK STFM again no...

Thanks for your responses guys. I never apply much force ever while any power is applied to any motherboard. If I do its only to see if a socket may be flakey or continuity is flakey. The blitter socket was only soldered in place. The W bridges were left as they were and the socket left unpopulated....

Hiya Atari Gurus. This project started as a use for my spare PAL STFM that was only blessed with TOS1.02 and 512k of ram so was basically not good for much. I already own a 1mb PAL STFM with a GOTEK drive and then only this year was lucky enough to finally score an STE which I upgraded to 4mb and I ...

Hi Guys Thought I should update what transpired. I changed PSUs. No change. Then I resoldered and refluxed all joints on bottom of board. No change. To be sure I also replaced r71 r72 and r73 with 68 ohm resistors too. Then I had the bright idea of shortening the yellow kynar MMU wire as I was worri...

I am more concerned about damage to the MMU. Its strange that it worked long enough for my floppy to be detected and sysinfo to run. Luckily I took a photo to show a friend within a few seconds and then I exited sysinfo to run the ram test tos file. It was during the ram test that it seemed to stop ...

Not good news today. I jumpered the board into 4mb mode and Sysinfo briefly displayed 4mb. Then the screen briefly displayed corrupt graphics and 4 bombs came up. I had no choice but to reset the machine and then after that all I could get was 1mb of ram to come up in Sysinfo. Very strange. I have t...

Yep and Okay it was. Kludged it back together tonite and up came 1mb of ram and the ram test passed. I will jumper it to 4mb and retest this weekend and then on to Install the 2.3 accelerator and matching 1.04 and 2.06 rom switcher. Exxos I also want to solder in that crazy blitter socket in. Ive ex...