Atari 7800 issues in 2600 mode

[6502_inside]

Atari 7800 works flawlessly in 7800 mode, however in 2600 mode i have some issues.

I have intermittent video issues.(shown in video below)

If i set the rf out to channel 2 the audio is noisy, but it is perfectly fine on channel 3.

http://www.youtube.com/watch?v=yCcybh0YPt4&feature=youtu.be

Does anybody out there have any idea what might be wrong?

 

Other Notes.

I have replaced the 7805 recently(shattered the old one).

I replaced the original power supply with a 7.5V one from a psone the video issue seems to happen less often.

[SoundGammon]

Isn't there a big capacitor by the 7805? It might need replacing. They dry out.

[Trebor]

If i set the rf out to channel 2 the audio is noisy, but it is perfectly fine on channel 3.

Does anybody out there have any idea what might be wrong?

 

Yes...You may be receiving some station/broadcast interference on channel 2 that is not present on channel 3 that is evidently triggered with the 2600 mode.

 

Just do not set the RF to channel 2. Leave the RF set on the perfectly fine channel 3.