User avatar
cgoff

Posted Sat Feb 13, 2021 5:37 pm

Recently I have come into possession of an Amiga 500 (NTSC REV 5). At first the machine worked very well. However, just the other day I ran into a problem.

When I fired up the machine the colors were all messed up. It appeared to only have red and green colors. Then shortly after only green was present. Just to be clear, this is not the "green screen of death", I can still play games and load programs just in a completely green hue.

I have tested this on a 1084 monitor with original cable, and through an OSSC with VGA and SCART. All show the same problem.

Is there anything I can do, or a resource you all can point me to, in an attempt to remedy this? Thanks for any help.

User avatar
obitus1990
New Orleans, LA, USA

Posted Sat Feb 13, 2021 8:00 pm

Do you have a spare Denise chip you can try in the board? That's about the only "simple" thing to check...all the other components in the video circuitry would have to be desoldered to replace them.


Go use the Amiga PCB explorer (https://www.amigapcb.org) to trace signals to see where they lead, and, in your case, where they disappear. Do colors change when you wiggle the video connection? Could be cracked solder joints at the DB23 video connector. Could be the video hybrid. Could be any number of passives in the video circuit, or the 7HCT245 octal bus transceivers.

User avatar
cgoff

Posted Sun Feb 14, 2021 12:38 am

I actually have ordered a spare denise chip. It is due on soon. Thanks for the link... Ive been searching for a resource like that





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