1947 Crosley 307TA (630 clone) issues

[earlyfilm]

Originally Posted by Phil Nelson

The problem seems to affect pic & audio signal equally, so that narrows things down.[/url]

I agree with Phil's recommendations and suspect that the problem is either in the tuner or the picture (contrast) circuit.

You may have or may not have two problems here.

The earlier missing sound on some channels indicates more probably tuner and the clicking in and out suggests picture control or related circuit.

Since the contrast control sets the gain of the tuner, it can also muck up the sound.

If tubes make no improvement, download the RCA 8TS30 / KCS 20J-1 manual at

http://www.earlytelevision.org/tv_sc...s_postwar.html

and using a VTVM run the voltages tests on V!, V2 & V3 shown with the picture (contrast) control set at both maximum and minimum.

If any voltages are off more than 20% find out why.


Also, the set is quite heavy and if it accidentally slides into something while being transported and the channel knob gets pressed in, that can cause problems in the waffer switches. Inspect the switch for bending damage and carefully clean the contracts. Allow solvent to dry over night before turning set on.

James.

[DaveWM]

AGC (if it has one) get bumpped? never mind just looked too early no agc. agree with others seems like tuner.

[Kamakiri]

Son of a B, I never thought of AGC. This has all the symptoms of AGC loss.

Now in the pic below, there's no AGC listed, just a "peaking" control. Is that the same as AGC?