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Khyron · 27 July 2012, 22:08

Start with the basics..
measure the supply voltages at each part for:
U31/U32 (Pin20), U12 (Pin 19&12), +VID for the Restor DACs & Buffers (Q211-Q213), and +VOUT (Q231-Q233) for the output buffers..

If you have a scope, you can do a quick test on U31 & U32 and just compare the input vs the output of each color bit on each buffer to see that they're the same while the amiga is sitting at the insert disk screen, there should be enough bit movement to see what is going on.. and do the same type of check for the RGB input on U12 vs the RGB out of U12, and the RBG out of U12 vs the RGB at the DB23. These test should pretty much localize the problem to a specific part.

The dacs on the A600 are just a simple restor ladder highly doubtful they're damaged...
The CXA1145 is a little hard to find, but you can usually salvage them out of game consoles.. or ebay.. the Erso ES71145 and the fujitsu MB3514 are also compatible parts that should be easier to find..

and good luck!!

27 July 2012, 22:08	#2
Khyron Registered User Join Date: Feb 2010 Location: SnowLand, Canada Posts: 74	Start with the basics.. measure the supply voltages at each part for: U31/U32 (Pin20), U12 (Pin 19&12), +VID for the Restor DACs & Buffers (Q211-Q213), and +VOUT (Q231-Q233) for the output buffers.. If you have a scope, you can do a quick test on U31 & U32 and just compare the input vs the output of each color bit on each buffer to see that they're the same while the amiga is sitting at the insert disk screen, there should be enough bit movement to see what is going on.. and do the same type of check for the RGB input on U12 vs the RGB out of U12, and the RBG out of U12 vs the RGB at the DB23. These test should pretty much localize the problem to a specific part. The dacs on the A600 are just a simple restor ladder highly doubtful they're damaged... The CXA1145 is a little hard to find, but you can usually salvage them out of game consoles.. or ebay.. the Erso ES71145 and the fujitsu MB3514 are also compatible parts that should be easier to find.. and good luck!!