atari Atari RF Modulator Tuning

[mathflicks2901]

Hello everyone, 

 

One of my light sixers has been suffering from awful static and strange noises when I turn it on. The voltage regulator, channel select switch, and power switch have been repaired/replaced, yet it still doesn't work. I was thinking that it may be improper tuning on the rf modulator. Unfortunately, all of my allen wrenches cannot fit the hole in the modulator (either they are too small or too big). Is there any specific size or brand I should use? Maybe I should replace the entire rf modulator instead? Thank you for responding,

 

Matt S.

[ChildOfCv]

Get an electronics alignment kit.  It comes with various sizes, and one of them is correct.  The tools are also made not to affect the characteristics of the coil just by touching it, so that the adjustment still works after you pull the tool away.

[+DrVenkman]

I've never had a VCS/2600 cross my path that had an RF modulator that needed adjustment, so on the off-chance that is not your problem, you might consider replacing the green chiclet-style caps on the switchboard, especially the one immediately adjacent to the the voltage regulator. They can and do go bad (unlike most other caps in old Atari systems, most of which have lasted very, very well over the decades). It's a different motherboard design of course, but the 4-switch models use a very similar power supply circuit. I had a Vader that had problems very similar to what you describe as a result of that cap going bad.