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[wa2ise]

Originally Posted by stromberg6

Has anyone had the tuner in one of these draw excessive current after warmup? Picture fades to blank raster after about 7 to 10 minutes.

I'd check any caps that are filtering the AGC line. AGC control lines are high impedance, and any leaky capacitors will overwhelm the AGC and cause the tuner and IF strip to cutoff. As you mention excessive current, this cutoff is likely due to the RF and IF stages going fully saturated. AGC voltages are usually negative voltages of a few volts, and more negative voltage reduces gain, and a lower negative voltage gives more gain. 0V would be higher gain, or saturation of the tube amps severe enough to not allow any RF or IF frequency to get thru.

A crude test would be to measure the AGC voltage when the set is first turned on and operating normally, and then watch to see if the AGC voltage changes as the signal gets lost. Then you could impose an external voltage on the AGC line the same as the good AGC line voltage to see if you get reception back.