Picture variation

[stevseluk]

Every time I use my 7800, the R/F varies slightly so I have to fine tune the TV every time I use it. Also it seems to change as time passes. Actually the picture quality gets better after about 30 minutes (if I retune the tv). Does this mean my 7800 is on its last legs or is this a common problem and if so is the only way to cure it, a mod job?

 

Cheers

[+-^CrossBow^-]

sounds to me like there is a semi cold solder joint in the RF circuit of your 7800 in the RF tuner of your TV. The reason the picture improves after the systems have been on for a bit is because the heat build up in the TV or the 7800 actually expands the contacts of the components in the circuit and hence they actually improve their connection.

 

I may be off base...but thermal migration is the only thing I can think of to cause this.

[Clock]

My Pal 7800 does the same, but when I removed the large metal RF sheilding from inside, my picture remains pin sharp and in tune.

 

I do not understand why, or whether it interferes with other equipment now that the sheild is out.

 

I only removed the sheilding whilst trying to convert console to S-Vid connection (unsuccessfully by the way). I put the sheild back in and hey presto, it drifts again.