G'day from Australia,
I am attempting to repair an A2000 board for a mate that has been looked at by several people before me.
When I got it it was in the following state... Original Elec Caps, someone had replaced Gary socket, and corrosion was evident on CPU and ROM sockets. CPU socket was also mangled from third party under CPU add ons.
Would boot to Light Yellow/olive screen. CPU would NOT fire and no serial output from Diag ROM.
I replaced CPU and Rom sockets, tracked a dry.cracked trace to from CPU E to gary. Have checked all Commodore Chips and replaced with known good. This got unit booting with Diagrom. Ran Memory Diagnostics and all passed, IRQ passes, BUT during CIA testing on EVEN CIA fails at TICK/Vsync test and crashes with illegal instruction.
I have attached Pictures.... cant cat exact moment Even Vsync test dies, but it is as soon as it starts.
Real world symptoms when i put kickstart in, is unit will boot to insert floppy, but floppy drive clicks twice and returns to insert disc.
So, I have desoldered and checked the memory, also replaced with other known good.... No Change
Desoldered all logic I could see associated with Floppy, so U108,U203,U900,U303 and even U204 amp. Checked in TL866 and all fine.
Any ideas from the boffins would be appreciated before I start desoldering everything.
Thanks
Paul In Australia...
