Disclaimer: the component designators in the attachment are fuzzy and I may not have read them correctly.

Procedure: disconnect C1a positive and L1 from pin 2 of 5U4. Measure resistance to ground at pin 2 if the resistance is that specified in the service literature or higher then the shot is not in the tube or power transformer (but if it meaures well below spec resistance spec the tube socket and or power transformer are prime suspects).

If you cleared the power transformer of suspicion next disconnect L1, R95, C2b, focus control, and focus coil from each other. Check resistance of C1a, C1b, and both wires of L1 to ground...if any of them measures less than 1M to ground replace the part that has low resistance.

Check R95, focus pot, and focus coil to ground. If R95 checks lower than 100k to ground you may need to check the circus it feeds off the image you attached. If focus coil checks under 100k to ground unhook the other focus coil lead and measure each lead to ground if still low replace focus coil. If focus pot tests under 100k to ground disconnect it's terminals from circuit and measure from each to ground. If still too low pot is defective.
Also disconnect the positive of C1c and measure it's resistance to ground. Do the same for R94...if you still haven't found the short check the items off the attached image that the B+ drives.

Methodically divide and conquer...er um I mean measure till you find your shorted part(s). Replace culprit part(s) remeasure, reconnect all disconnected connections, remeasure to be sure the short is gone, and then power up if all now checks good (use a variac and or dim bulb tester if you have one just in case something is still wrong).

Sorry about the fuzzy diagram the Sam's Folder came to me that way when I downloaded it from the Sam's website.

I'll definitely check those things out for sure.

But by all means start with this from Electronic M:

With C1a+ and L1 disconnected from pin 2, you should read infinite resistance (open circuit) from pin 2 to ground. If so, that eliminates 5U4 socket and xfmr as suspects. Then proceed 'downstream' per Electronic M's directions.

I forgot about the focus coil circuit!
The last three sets I restored had PM focus units or electrostatic focusing. :scratch2:

Wow there are more posts about this set than there are Parts in it LOL

Whomever said it was easy to teach troubleshooting skills via the internet was mistaken. ;)

Yeah, I wish there was someone nearby that could help me with this but unfortunately none of you here live nearby where I live.

I really do want to get this set going because it is such a rare set and also this would be the oldest tv I've ever owned.

Vortalexfan, how are you doing with this, are you making any headway?

Unfortunately no, I'm no closer to figuring out what's causing my 5U4 tube to arc and red plate than I was a couple of weeks ago.

I've been testing various components and replacing suspect capacitors in the power supply and I'm not getting anywhere.

So what did you find out when you followed Electronic M's below procedure?

I haven't had a chance to try it yet.

I'm actually kind of afraid to disconnect the wires from the rectifier tube socket because I'm afraid I might accidentally reconnect them wrong and screw things up even more than they already are, especially since I don't which wires are the wires that Electronic M is talking about.

I did post a schematic of the power supply for this TV on here, if someone could mark on the power supply which wires are the ones I need to disconnect and test I can get a better idea of which wires to disconnect and test without risking disconnecting more wires than need to be.

Can you take a picture before you disconnect the wires so you'll have a reference to get them back to original? Not trying to be rude, but you need to take the initiative to follow directions and report back if you expect folks to help you troubleshoot this. If I can get the picture to load I drew a red line thought the connections you'll need to open.

https://live.staticflickr.com/65535/...a4826e45_z.jpg

That's the thing that L1 coil doesn't seem to be present in my TV, the Focus coil is there but that inductor coil or whatever it is that L1 is supposed to be doesn't seem to be present in my TV, at least not that I can see of.

I'll take a picture of that part of the TV so you can see what I mean.

Below is a picture of the power supply circuit on my TV showing that L1 does NOT exist in my set (at least not that I'm aware of).

L1 is the small transformer(filter choke) to the left of the power transformer in your photo. Right above those electrolytic caps you've replaced. I can read the part number LG-10021 in your picture. There's only 2 wires exiting from it. One of the wires should go over to pin 2 of the 5U4 socket. It's also shown on page 4 in sams set 101, folder 5.

All you should need to do is remove the one small white wire from pin 2 of the 5U4 socket. If you follow that white wire over to your terminal strip it should connect to the plus end of one of the electrolytic caps and also to one of the black wires that goes to L1. It's possible you have a wiring error on your terminal strip, but for starters remove the white wire from pin 2 and see if that fixes the excessive current draw problem. Looking at your picture it seems to me that you have that white wire from pin 2 going to the negative side of that cap?

https://live.staticflickr.com/65535/...00e02f87_z.jpg

now wait, L1 is the Focus Coil, which doesn't make any sense because L1 and the Focus Coil are marked as two separate items on the schematic...:scratch2:

Nope. T6 is the focus coil and it's mounted on the neck of the Picture tube. L1 is the small transformer(choke) mounted under the chassis as I have it marked.

Dude, take a deep breath and just clip the wire goin' to pin 2.

Now, measure from pin 2 to ground. If infinite resistance (open circuit), tube socket and power xfmr are not suspect. Short is 'downstream'.

I unsoldered the wire and then tested pin 2 and it measured infinite like it should.

So where should I check next?

How many ohms is there between the ground and the white wire you unsoldered?

There is 256.6 Ohms between ground and the white wire that I unsoldered from pin 2 of the 5U4 tube socket.

Is that white wire connected to the same point as the negative side of C1A & B as it appears in your picture? If so it needs to be moved to the plus end of C1A. Also check to see if R93 is in fact still 15 ohms.

That seems quite low, some of that could be the electrolytics loading the circuit down as they charge. To me it looks like its ahead of the transformer and rectifier.
You could power it up and watch the rectifier tube for arcing, and red plating.

It was but then I switched it around once I realized it was hooked up wrong.

I powered it up with that white wire disconnected from the 5U4 tube and it didn't arc anymore.

I'm guessing that means that the Filter Choke may be bad? How hard is it to replace those and how expensive are they to buy? Also how necessary is it to have that filter choke in the circuit? Can the set be ran without it in circuit?

without that white wire attached to the 5U4 tube socket the tube doesn't arc anymore which I'm guessing means that the filter choke is bad.

All it means is that the power transformer and tube, and tube socket are good (and that the short is inor down stream of L1). You need to confirm L1 is bad by unhooking both leads on the choke and measure resistance of both to ground and confirm it is a measurable/low resistance to confirm L1 is bad. If L1 is infinite resistance to ground then it is good and you still need to find the actual short.

Gotta keep dividing and conquering... you've cleared some of the more important parts, and found a a direction to follow to find the short. Keep at it.
Don't let yourself get lazy or confused.

Ok. Just curious but can a filter choke be wired up backwards, or does it not matter which way it's wired up?

OK, so you switched it around. Have you powered up the set with the white wire connected back to pin 2 of the 5U4 since you switched it? If you previously had that white wire going to the negative side of the C1A, & B caps, that alone explains why the set was drawing excessive current, because that point connects to the center tap of the high voltage windings. Normally there would be 15 ohms from that point to chassis ground, which is why I suggested you also measure the resistance of R93(should be 15 ohms)

Don't worry about replacing the choke until you know it's bad.
Heres how to test it.

There' a black wire that is connected to the filter choke that leads to the lower end of the terminal strip where the electrlyics are connected.
I can't see the other wire that come from the choke, but it too should be at the terminal strip. Mark these so that you can connect them back in the same places.
Unsolder these wires and and see if you can get any resistance between it and the chassis.
The reading with both wires off the choke should be infinity or at least in the several megohm range between the chassis and one of the choke leads
The reading between the 2 leads off the choke should be low. Somewhere around 3 to 20 ohms for example.

I did try it out with the wires switched and it still arced, but not nearly as bad as it did and the tube wasn't trying to red plate either like it was before I switched the wires.
Basically its doing the same thing it did before I replaced the power supply caps.

OK thanks, I was just getting ready to do that.

Then by all means do as Electronic M suggested and check resistance from each lead of L1 to chassis ground. You may need to disconnect both L1 wires from the circuit to get an accurate reading.(as Tube TV said above my post)

I checked the filter choke with my ESR/LCR Meter (which also checks resistors and resistance loads) and the filter choke checks out within tolerance of the original specs given in the Sam's Folder, it checked at 27.7 Ohms and 1.69 Henries, which the original specs given in the Sam's Folder for the Choke is 32 Ohms and 1.5 Henries.

As for the individual leads checked to ground, one lead read 254 Ohms and the other lead measured infinite.

The filter choke is definitely necessary for proper power supply operation. It’s easy to install - there are only two leads. The bigger problem would be finding a replacement.

[Edit] I'm not sure how it can measure 27.7 ohms across the two leads and be infinite from one lead to ground. But it's bad none the less. ;)

Well I just tried measuring the individual leads again and now both of them are measuring infinite to ground, which I'm not sure how that's possible, as you said. But of course I'm not sure if I had all that good of a connection between the multimeter probe and the wire coming out of the choke which when you have your multimeter on your workbench top and the choke wire is hanging in mid air its kind of hard to get a solid connection without using aligator clip leads, which I have but not for my multimeter.

That 254 ohms from one lead to ground reading indicates a short to ground in L1 ( I assume you unsoldered L1s leads from the rest of the circuit)...........
.... however I'm suspicious of that readinds accuracy.
If you measured from 1 lead to another and got 32ohms, then measured 1 lead to ground and got 254ohms to ground then logic says the other lead should have in the neighborhood of 222 to 286 ohms to ground instead of open circuit that you measured(that or the 32 Ohms across the leads is actually open circuit)....

L1 probably is bad but I'd like you to redo all the measurements on it you just made to confirm no mistakes were made, and hopefully this time not obtain numbers that together should be impossible for this part.

Edit:I see progress was made while I was typing.
Do you you have alligator clip leads with an alligator clip on each end of the wire? If so clip one end to a probe on your meter and the other to the test point in circuit. You can do that for both meter leads to do hands free measurement. This may add as much as an ohm to a measurement, but in most tube circuit work that is too small a difference to matter.

No I don't unfortunatly do not have double sided aligator clips.

The aligator clip leads are on my ESR/LSR Meter leads, which I did try to use as stand alone aligator clips to clip onto the filter choke lead on one end and then take the other aligator clip lead and clipped it to the multimeter probe and the banana plug end of the aligator clip lead that was attached to the filter choke lead and I was still getting an infinite reading (O. L.) on my multimeter for both choke leads, so it seems that the filter choke is bad.

Also wiggle the wires on L1 while rechecking for the short to ground to rule out a possible intermitent short . To be at infinity on one side of the choke is not possible.
The choke is simply one long run of wire on a transformer core.
Edit: also make sure that when testing one lead on L1 that the other lead is not touching the chassis or other parts in the circuit.