The Emperor is full of hacks (25MC46Z)

[ctc17]

One of the power supply filter caps must be dead so someone bridged it with that hacked in cap that fell off.

The thing you are calling a disk cap looks like the degaussing thermistor to me. It looks like on of the leads separated? they do exactly that when they fail. The set will usually work without that but the purity will never be right. Those are an easy find from Moyers.

I would replace that filter with another 100 at 450 in the same fashion if it were my set. The thing was working so no reason to risk screwing it up.

On second look it looks like the old thermistor fell apart and they soldered another one in. If the degaussing is working I would leave that thing alone. You may destroy it trying to desolder it and clean up the tacked in repairs. Those things are like little charcoal briquettes with wires cemented on the sides, touching it wrong will turn it to ash.

[Carmine]

Originally Posted by ctc17

One of the power supply filter caps must be dead so someone bridged it with that hacked in cap that fell off.

The thing you are calling a disk cap looks like the degaussing thermistor to me. It looks like on of the leads separated? they do exactly that when they fail. The set will usually work without that but the purity will never be right. Those are an easy find from Moyers.

I would replace that filter with another 100 at 450 in the same fashion if it were my set. The thing was working so no reason to risk screwing it up.

Power supply filter caps... Not the same as electrolytic cans, right? I'd rather not replace it like that, and wire it under the chassis. (it's already out, lol) The other end of the cap is soldered to the terminal strip that has RGB wires running to the CRT. The particular terminal simply connects to the chassis through a soldered rivet.

I have a pretty good local electronic supplier... I could ask for the thermistor if you can tell me an electrical rating...?

[DaveWM]

agree with CTC17, the 100uf 450v is a replacement for an open section of one of the filter cans, the other is a Thermistor. Those zenith chasssis that use that style of term strip make for convienent test points, and in this case a quick fix from the top of the chassis (the orig service guy prob did not want to pull the chassis, and since its a combo, did not want to flip it over to get at the service saver plate on the bottom).

since the orig prob was the blue gun, you should test the CRT, then check the voltages at the CRT pins, wiggle some of the demodulator tubes. Scope the grid of the Blue gun at the crt and see if anything is going on. Looks at the screen voltages of the CRT with a vtvm compare the blue to the other two guns.

Careful handing the zenith chassis with it out of the cabinet, there are a lot of parts leads that can short if a part is moved around by handling. I set a chassis down on some soft padding for transport, the padding pushed up, came into contact with a large disc cap, moved a lead into something it should not have been, ended up with a difficult to find hum bar.

[Carmine]

No luck getting a cap that big from my local parts house (but they do have thermistors.. I just need to know the specs).

So I went to a local TV shop that has a LOT of flat screens on the bench, and asked if they would just sell me a cap. They offered a 150mfd @ 450 cap that looks like it was removed from a power supply board. They said it would be close enough? What say you all? I took a shot of it on the chassis which I carted up in the trunk of my car. They didn't know what size thermistor I'd need... Do any of you? I had some Zenith schematics for this set, but can't find them.

Hopefully this pic works (posting from phone again)