Corrupted graphics

[Misko78]

Few months ago i took out 8372 Agnus out of the 6A board and installed it into Rev5 board to make it 1MB chip compatible, and bought another one for 6A from Vesalia shop. Few nights ago i popped in new chip into 6A and since then i get graphical issues. Screen is garbled completely, when i load anything, the Amiga boot screen with diskette look normal and i've tried 1.2, 1.3 and 2.04 roms.

1. Amiga test kit gives completely corrupted graphics after a minute or so, with 8371 chip i have graphics are corrupted but not to the extent as with 8372. Rick Dangerous game gives me solid 5 minutes of gameplay before corruption starts, but i hear subtle pops and cracks in audio.
2. I've replaced the U2 socket, issue stays.
3. Tried 8372 in rev3 board and it works normally
4. Checked all custom chips in rev3 board and chips are OK.

As i read the A500 troubleshooting list all of this points to U2 socket (replaced it), Agnus (it works on another board) and Denise (works on another board).

[Leon Besson]

Originally Posted by Misko78

Few months ago i took out 8372 Agnus out of the 6A board and installed it into Rev5 board to make it 1MB chip compatible, and bought another one for 6A from Vesalia shop. Few nights ago i popped in new chip into 6A and since then i get graphical issues. Screen is garbled completely, when i load anything, the Amiga boot screen with diskette look normal and i've tried 1.2, 1.3 and 2.04 roms.

1. Amiga test kit gives completely corrupted graphics after a minute or so, with 8371 chip i have graphics are corrupted but not to the extent as with 8372. Rick Dangerous game gives me solid 5 minutes of gameplay before corruption starts, but i hear subtle pops and cracks in audio.
2. I've replaced the U2 socket, issue stays.
3. Tried 8372 in rev3 board and it works normally
4. Checked all custom chips in rev3 board and chips are OK.

As i read the A500 troubleshooting list all of this points to U2 socket (replaced it), Agnus (it works on another board) and Denise (works on another board).

Then by testing the above, you have a problem on the mainboard

When you were removing and pushing in Chips. Was this done on a flat surface?
If not, you may have put too much pressure in the mainboard and have caused a break somewhere.

[Misko78]

I am very careful when inserting or removing ICs. There is no apparent break anywhere.
I've also removed dram chips, placed sockets instead as well as known good chips. No difference.

[Misko78]

Changed the dram chips, changed logic chips in data path...

And all the work for nothing, today i've finally got my hands on a working rev6 board to make comparisons of resistances, and for the sake of sanity i've tried my agnus in this board and vice versa. Agnus is toasted, only mystery is how it works in Rev3 board