My Philco 1884 has developed issues with horizontal control. Adjustment with the hc knob has resulted in very brief if instantaneous horizontal hold. I have substituted tubes in the circuit with no improvement. Studying has lead me to the HV rectifier tube. I have substituted tubes and tested tubes to realize it is not a tube problem. I now have no picture but sound. I have not checked CRT nor have I checked any voltage anywhere yet. As a very eager yet less knowledgeable hobbyist, I welcome your assessment.
Dan

Your initial symptoms followed by a loss of picture altogether leads me first to perhaps looking for an arcing issue. Usually sync instability can be traced to an ungrounded external conductive coating (aquadag) on the kine, such making it impossible for the tube to act as a final filter capacitor for the HT. This can lead to horizontal sweep frequency spikes electrostatically radiating from the ungrounded coating and interfering with circuitry that should count on such sync pulses from the received signal only to keep the sweep in sync. This conditon will obviously lead to trouble.

Now it is also possible that you have instability issues due to a defective horizontal hold pot if that is what is used, or a bad horizontal oscillator coil, or a poor solder connection. Such may have been intermittant at first to cause your instability issue, followed by out and out failure of the connection altogether....

Can you hear the 15.75KHz whistle as it should sound normally. (I did as a kid, and could diagnose a horizontal sweep/ HV problem in a heartbeat just by the volume of the whistle--but as an older fart no longer can as readily. :( If you can then that is to your advantage--if you know what it should sound like for that set. You can also take an NE-2 neon bulb test light and ground the leads, and hold it close to the HV lead. It will readily glow if HV is present.

If the latter-mentioned condition be closer to what you are looking at you will need to do some deep sleuth work, and check over the horizontal drive circuitry with a fine-toothed comb. Beware in the troubleshooting process that if you are operating your set and there is no horizontal sweep signal to the output tube then that tube can cook itself to death in short order owing to lack of drive derived negative bias on its control grid. Keep an eye on its plate for an increasing orange glow.

Yes, I have hearing like a dog and hear high pitched sounds, and do hear the whistle. While my hearing is quite good at an age of 51, my eyesite is dismal and must rely on sources of magnification at near and far vision. Looks like I need to check voltage levels, I will refer to my Sams and hunt down my good volt meter for testing.
Cars = EZ, Tv's = rocket science to me lol. But by gosh, I do love learning.
Dan

That model number shows two very different chassis. Can you provide a run number or chassis nymbers? Run will be either 123 or 125. Chassis will be RF84deflection H4 or RF 44, deflection G4.

Don

Don, on one side of the chassis it has RF 44 stamped, then on the other side of the chassis stamped on the high voltage cage is G4. While I have not been able to check actual voltage I believe the high voltage to be too low as there is a very dark picture. Learned that last nite working in a dark room going over some of the grounds.
Dan

Dan:

Does the dark picture look normal otherwise? It it in sync and normal size and shape? Are you using the CRT from the TV or a test tube? Does the brightness control function normally? Lightly tap the CRT neck and see if the picture flashes back or streaks. If so, that's the trouble.

Otherwise, measure voltages on the CRT socket. The screen should be four hundred volts or so. The control grid and cathode will vary, but the cathode should be about 25-75 volts more positive than the grid. It will vary with brightness control setting.

Don

Sync is lost and size and shape are reduced. CRT is being used by the TV. Brightness control has no effect. I have tapped on the CRT neck and no change. Still have not checked voltage on anything due to a failure to my good voltage tester.
Dan

Dan:

Check the B+ for 260 or so. If it is way down, suspect electrolytics; particularly the input cap in series with the AC and rectifiers. Others in the power supply could be on the verge as well. Best way is to simply bridge the old one with a known good one. A 40-60 uuf @ 450 will give you an indication. Once a bad one is confirmed, replace it with the correct value.

I do not recommend a wholesale change out until the diagnosis is complete and the set is operational.