Atari VCS help needed

[dougtitchmarsh]

The story is that I bought a non working Atari VCS six switch woody to replace the case on my working one which was cracked. Now I can't find the working VCS to transplant the good stuff. So I bought a switch for the non working one as it was missing (actually found it inside the Atari but the metal shaft was broken off). Having soldered in the switch and plugged everything in, and using a cart which works in another Atari system all I get is a black screen.
I pulled out the boards and checked for obvious blown components, broken traces etc. but there's nothing staring me in the face. So does anybody have any idea for fault finding the system?

[TL]

No idea I am afraid

I have a woody that is exactly the same. It works but I just get a black screen.

[Carlos]

was this machine ever working for you? is it the spares one that is faulty?

[dougtitchmarsh]

No this machine was never working for me, it was bought for the case only but now I can't find the one which was to donate its innards so hoped a switch would cure this one. Also it looks pretty simple inside compared with stuff now so repairs apart from the major chips should be possible if I can get some sort of idea of diagnostics.

If all else fails it becomes a case for something else like a Raspberry Pi or Mini ITX based project again.

[Carlos]

try turning the rf trimmer with a small screw driver- if the picture fades in, then its you rf unit, the other thing it could be on a 2600 is the gubbins under the alloy cover itself.

[retromod]

if there is only a blank screen first check power voltage on the 7805. It must be 5V. if there are 5V then most likely the CPU is broken.

I've have had the same issue on a 2600 vader and after swapping the CPU it worked like a charm.
A new 6507 can be bought at ebay for about $4. For troubleshooting purpose simple replace the CPU with a working one (only possible on Vaders and Woodgrains, jr are soldered)