Quote:
Originally Posted by Electronic M
First off if you have discussed this TV on this website before please don't create new topics for it...Pick one of the topics you've made and reply to it when there's updates. It's important to keep all the discussion and info on the set in one place so we don't have to dig for it.
The black looks like it could be black corona dope (insulative paint) the doorknob could be good or bad.... visually there's usually no way to tell unless they're blown in half. Best way to tell is unhook an end (discharge the positive first so you don't get zapped) and stick that end in a shot glass or other small glass container so it can't arc when the set is running.. It's not why the brightness control tingles.
I don't know what model you have to look up the service info, but there are 2 kinds of TV power supplies transformer and hot chassis. Hot chassis sets tie one of the 2 wires of the unpolarized cord to chassis and depending on which way you plug it in the chassis and any exposed metal on the cabinet could be at 120VAC (most makes tried to insulate the metal connected to chassis to prevent touching it but whether the safety bits are still present and good who knows). Transformer sets aren't "supposed" to give you a tingle but can...if the transformer primary insulation fails the chassis can get hot, even if everything is working there's sometimes chassis to cord bleeder resistors that are designed for bleeding excess charge between the chassis and line back to line.... the bleeder resistors can give you a tingle but are designed to limit current to non-harmful levels.
Do you have absolutely no sound?... No static, no crackle in the speaker when changing channels or rotating the volume knob from stop to stop?
If so you need to get the schematic, and a DMM, figure out where to measure the B+ voltages and check them. I suspect your missing one or more B+ voltages or that they're more than 20% below spec (which is bad). The heaters run on the A power supply and it's very easy to have A but no B.
Now is the time for voltage checks and troubleshooting, not firing the parts cannon.
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I apologize, still a little newer and didn’t feel the past threads provided any insight much. Will do so from now on.
The TV is a 9121A. The chassis is not hot.
I am also noticing that when discharging the picture tube, the anode cap typically pops out easily without spark when applying a screwdriver + resistor. Not sure if that’s of concern, but thought I’d add.
Previously, I’d get crackling in the speakers prior to replacing all the resistors and deoxidizing the pots, but beyond this no sound. No static, radio, or anything else.
Again, I apologize for the additional post. Happy to share the schematic below (that was also shared with me). I have series A-C-D:
https://drive.google.com/file/d/1_EZ...N31OaxzqH/view