SEGA Genesis video problems

[Retrogamer]

SEGA Genesis model 1 has beautiful video (through RF) until screen goes white ex. "SEGA" logo screen when booting up Sonic the Hedgehog. upon hitting a bright or white background screen the color and sound go out, and the screen goes all floppy.
I opened it and the RF shield seems tight on all corners.

Any suggestions>?
Thanks in advance
George

 

[SmokeMonster]

Beautiful video through RF?! I'd suggest trying a composite cable. This will give you a significant boost in quality and help determine if the problem is related to your RF cable. Two birds, one stone.

 

[Retrogamer]

Beautiful video through RF?! I'd suggest trying a composite cable. This will give you a significant boost in quality and help determine if the problem is related to your RF cable. Two birds, one stone.

Its not for me, its one I have in my shop. I have no video cables in stock at the moment

 

[bustedstr8]

Sounds power related. My first two guesses would be either a tired 7805 or degraded bypass caps. The main bypass cap is in the wall wart.

 

[Joneo]

Years ago I had the exact same issue. Bright scene and video dropped out. My RF box had a switch between 75 and 1k ohms. I seem to remember it being much more stable at 1k. You could also try bumping your TV brightness/contrast down to see if that has any effect.

Ultimately, I'd say if you want awful-looking video and stability, move on to composite for the best of both worlds.

 

[Retrogamer]

Sounds power related. My first two guesses would be either a tired 7805 or degraded bypass caps. The main bypass cap is in the wall wart.

Can't be the culprit, as I used the same adapter to test another unit and it worked fine.