English Amiga Board - View Single Post - Help needed with a video fault on an A600

elmasta · 19 November 2007, 13:54

I am no amiga expert, but looking at page 5-4 of the service manual it seems it's some problem with Denise's inputs.

Maybe there are flipping bits in RGA (register address bus). But I think that would make the machine crash, which is not happening.

The other possibility would be flipping bits in DRD (DRAM data bus) but I discard that because that would mean every chip would be reading garbage instead of reading from ram and of course we wouldn't be seeing anything and the machine would have crashed long before the floppy appears.

Other possibilities are on the other inputs CCK _CSYNC _CDAC , etc..

any ideas?

(maybe denise is dying but I don't want to think that)

19 November 2007, 13:54	#11
elmasta Registered User Join Date: Sep 2007 Location: Uruguay Age: 41 Posts: 38	I am no amiga expert, but looking at page 5-4 of the service manual it seems it's some problem with Denise's inputs. Maybe there are flipping bits in RGA (register address bus). But I think that would make the machine crash, which is not happening. The other possibility would be flipping bits in DRD (DRAM data bus) but I discard that because that would mean every chip would be reading garbage instead of reading from ram and of course we wouldn't be seeing anything and the machine would have crashed long before the floppy appears. Other possibilities are on the other inputs CCK _CSYNC _CDAC , etc.. any ideas? (maybe denise is dying but I don't want to think that) Last edited by elmasta; 19 November 2007 at 14:02.