1947 Crosley 307TA (630 clone) issues

[Kamakiri]

Hey guys, any thoughts on this? Has me kinda stumped, offhand.....at least to the theory of what could be going on here....

[Phil Nelson]

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

Wild guesses follow:

-- Funky tuner? I have had tuners that blipped the picture & audio in and out completely if their contacts were dirty or worn out.

If the problem reoccurs when changing channels, try nudging the tuner, rocking it, etc., while changing channels. If the pic & audio come and go, that may be the culprit. I have even had tuners that only worked when you turned the tuner so that it "stuck" slightly off the normal detent position. The remedy is to pull the chassis and service the tuner.

-- Funky Picture control? The "Picture" control on a 630TS is a manual gain control. If it is dirty or worn out, that can have a major affect on the signal.

When the TV is playing, try turning the Picture control back and forth through its entire rotation. If that has an immediate effect -- either causing the problem or curing it -- you may have found your culprit. When pic/audio are present, note whether turning the control makes things change smoothly; if the change is jerky, the control may need attention.

Re-seating tubes and wiggling them is always worthwhile. Sometimes a tube or its socket will have stubborn oxidation or dirt (or the socket may even be loose) such that wiggling or re-seating only works when you happen to position it in exactly the right position. The remedy is to thoroughly clean every tube pin and socket hole so that you don't have to guess whether the tube is actually making contact. Dirty tube pins & sockets are an extremely common cause of intermittent operation and that's why I eliminate this cause before I do any recapping: http://antiqueradio.org/FirstStepsInRestoration.htm .

Those are a couple of not-very-scientific things you can try immediately. I don't know what instruments you have available, or how willing you are to pull out the chassis and get your fingers dirty. Smarter people may have better ideas.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[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?