Can't find my book!

[earlyfilm]

The first problem, is you don't say what era TV you have, or make and model and that prevents anyone from giving you specific instructions.

The left side picture defect sounds like Barkhausen. I say "sounds like," because a picture surely would help to confirm this. There also is a pretty good chance that you will invent a new cuss word before you find the cause!

The cause of this defect is electromagnetic radiation (or rarely electrostatic radiation) from the horizontal sweep that is being picked up somewhere between the antenna and video signal to the picture tube. Since there is a time delay here while traveling though the circuits the second time, the spike or spikes are shifted into the picture.

The below is general procedure for 1940 to mid-1950s electromagnetically deflected TV sets:

The usual cause for this is any tuner, IF or video tube that is missing its shield, or the shield is not properly grounded.

Or, the antenna lead is not shielded or possibly dressed too close to the horizontal output tube, the flyback or HV lead.

Or, if the antenna input is coax and the center and ground connections are reversed, as with a balun coil connected wrong. (This problem usually will come and go as the cable is moved.)

Or, the HV cage is missing or not properly grounded.

Or, aquadag coating is not grounded.

Or, HV lead not fully seated in the CRT.

Or, a current limiting resister in the HV lead is breaking down.

A remote possibility is lack filtration in the control circuit if your set has AGC keying.

On string filament-chassis, a heater cathode short can cause this.

Usually not, but I've seen gassy or slightly shorted tubes cause this. When all else fails, substitute one-by-one all tuner, video IF, AGC, and video amplifier tubes.

Now here is the kicker! Sometimes it goes away for no apparent reason, and only reappears when you clean up and put everything back together!


The second defect, having to move your ion trap, sounds like something such as the CRT, the yoke assembly or the focus assembly or focus coil shifted when you tipped the set.

Your two defects probably are not electrically related. (An exception to this might be if the current limiting resistor in the HV lead is failing.)


James.