Fairchild Channel F Repair

[CemeteryMan69]

I have a Fairchild Channel F that I believe has a problem with the psu. I've found a few things online that seem to match my issue.

When I power it on I get a garbled image onscreen and the tv still prduces the static sound.

Although I was able to find some info indicating the issue was with the psu, I have not found any info on how this problem might be corrected.

I have attached a pic of the video output on a CRT.

If anyone has any ideas, please let me know. I really want to get this old sytem up and running again.

[CatPix]

If the issue come from the power supply, I'll suspect bad capacitors.

Old system from this era will likely use different voltages; 12V, 5V for the RAM at least.

Your issue is more likely located on the RAM/ROM supply, so the 5V line.

So your first task is to locate the power supply output, and check the voltages.

 

Here are schematics :

 

As I suspected, there are 12V, 5V and a -5V for the RAM.

 

The schematics seems to show that voltage are fed into the motherboard by a connector, so that make your measuring easy.

 

If you get 12V, 5V and -5V (on load) then the issue is likely on the motherboard.

If one of those voltages are wrong, or all of them, then the failure is into the PSU.

 

I can't help you much more. I have an European VCS so the PSU, power requirement and hardware configuretion might differ enough. I'll try to get pictures anyway if you need them.