7800 only b&w

[Skarrj]

So I picked up this boxed 7800. There are no colors displaying in 7800 or 2600 mode except for yellow. Colors did appear for a moment but im not sure what i did to get them to come back. Ive fooled with both color pots without any success.

[+-^CrossBow^-]

Could be the RF needs to be adjusted. It isn't a simply pot like the others. Need a small hex wrench to place into the RF coil and adjust from there. I actually have the actual tool for it, but a small hex wrench should work as well. The coil is the red pole part that sticks up with the copper wire wrapped around it.

Edited July 4, 2014 by -^Cro§Bow^-

[Andromeda Stardust]

You'll need to use a plastic hex wrench to tune the ferrite nut on the inductor since a steel wrench will alter it's inductance and mess up the tuning when you remove it.

[+Trebor]

Ive fooled with both color pots without any success.

 

Unfortunately, the color pots you were adjusting modify the color phase shift of the console. The top pot (closest to the cartridge port) is for the 7800 mode. The one below it is for the 2600 mode. You will have somewhat of a chore to get those both back into a reasonable ballpark without referencing the CPS diagnostic cart for the 7800 pot, and the Color Bar Generation [1984, VideoSoft] for the 2600 pot.

 

Not impossible, just a tad bit difficult as both dials are extremely sensitive to the slightest adjustment and all (Atari 2600/5200/7800) consoles "auto" phase shifts a couple to a few degrees as it "warms up".

 

First things first though, you need to get colors back and both -^Cro§Bow^- and stardust4ever provided you with some good direction. When (if?) you get colors back on your console, we can tackle getting the pots back to hopefully providing reasonable levels of phase shifting (~24-28 degrees shifts).