GENERAL TIPS

[exxos]

MACHINE DEAD ST/E/F/M/MEGA
If there is no lights on the keyboard either power or floppy , then likely the PSU has died.

2 or 3 BOMBS ON POWER UP TOS206
Normally bad floppy drive or bad power or ribbon cable to floppy drive. Possible could be damaged WD1772 or other IC's but in general its the floppy drive itself.

VIDEO SYNC PROBLEMS STF/M
Generally the video caps need to be replaced. See here. http://www.exxosforum.co.uk/atari/last/S ... /index.htm

WHITE SCREEN ON POWER UP ST/F/M/E/MEGA
Generally machine not running TOS from ROM for some reason. Either bad connections on ROM sockets, bad or incorrect ROM IC's. Can also be bad connections on MMU, GLUE, CPU etc if socketed.

FLOPPY DRIVE READ ISSUES STF/M/E
Drive heads need to be cleaned with IPA or suitable floppy disk cleaner kit. Also can be related to lack of pull ups on the DMA data lines. See section "September 1, 2015 DMA FIX & TESTINGS" here http://www.exxosforum.co.uk/atari/last/DMAfix/index.htm. Can also be bad PSU.

HARD DRIVE WRITE FAIL STE
Hard drive (and floppy drive) problems start with aged unserviced PSU's. Research has shown hard drive problems are related to the brand/type of ROM's fitted along with the brand of CPU. If you have a -38 DMA with a Motorola 68000 CPU, then you must change the CPU with a 68HC000 CPU. See here for my research on write failure issues and general research into DMA related issues. http://www.exxosforum.co.uk/atari/last/DMAfix/index.htm. Hard drive issues may not be related to the motherboard and could bad drive media or bad drive PSU etc.

VIDEO GHOSTING WITH RGB STE
Lack of proper regulation on the 8V supply rail for the STE's video circuit. See here for a fix. http://www.exxosforum.co.uk/atari/last/V ... /index.htm

LONG BUTTON DRIVE NOT WORKING
Long button drives are sometimes single sided drives. So try formatting a floppy in GEM on single sided setting. Also a lot of these drives were belt driven, high possibility the belt has snapped.



If you have any hardware repair tips then let me know and I will add it to the list!