Finished the electrolytics. The can in front is made from a cardboard tube. I used narrow metal strips for the hold downs-- It was a big hassle but it's in there solid. The back two cans I cut in place and used aluminum in strips with epoxy to put them back together. Since this was the first time I've stuffed cans it was a little awkward. I'll definetly look for different sized caps next time. The yoke covers them pretty completely so I'm not going to get too obsessed.

Finally had a chance to replace some more caps and resistors. I've been real careful to trace each one on the schematic and mark it off. I've also been replacing resistors that have drifted more than the 10% recommended as well as some that were close to going over. The sand resistors were also replaced. I ended up using two in series to get the correct value.

Once I get done with that section I'm going to go over it one more time and check the resistors, connections for cold solder joints and check all against the schematic. I also inspect for shorts and debris. An ounce of prevention....

Noisebox, I've been following your resto and am really learning from it and enjoying it as well. I'll continue to follow it as I get ready to start on re-capping my Zenith 24H21. Can't remember which chassis yours is but it must be the same or very similar judging from the photos you've posted. Steve

Hi Steve. The chassis is the 23G24. I haven't done a lot of restorations in the four years I've been doing this but I'm finding out I have to fight my nature--which is impatient! It pays to take things slow and double check the work. I'm learning a lot from this one and it's great having help from the pros as well. Post a link to your restoration when you get a chance.

Curious, when you removed the Ion trap sleeves and rings, did you have to have to expand the rings or mark the location/orientation? I am attempting the same restoration on the same model (picked up this past weekend), but am cautious about removing that section from the crt neck. I guess the re-alignment proceedure will be discussed at a later time. Great thread you have here, Noisebox, and great timing!
Keith

Keith, the CRT won't come out unless the trap is removed. I was able to rotate it slowly and pull it over the end of the CRT. I don't think I had to spread the back ring much, if at all. I think I used a bif flat head screwdriver to do it. I took a few photos to make sure it's put back as close as possible to the way it was originally. Just take your time and don't force it and it'll be ok.

Some ION traps have a thumb screw to tighten it once you find the optimal position.
I've seen others that have sprung grips that spread apart so that you can just pull up and off:


This one has a thumb screw that you loosen and slide off the back of the CRT neck:


Take a digital picture of it before you remove it - and write an arrow on the ION trap pointing to the front. ION traps work one way.

Carl

It just looks black to me, so the value would be 0.1uF/200V.

Noisebox - Here you are:

http://videokarma.org/showthread.php?t=254091&page=2

I've just done some preliminary stuff. Won't get into the recapping, testing, etc
until my friend Bob has time. He's much more knowledgeable then I. So far most
of the Q's I've asked and had great answers are on videokarma. I read this one
for your resto though.

Yes--it was .1
I'm finding it's easier and faster just tracing the caps through the schematic to ID them. It intimidates me a little but it's a great way to get the lay of the land.

I've been sick the past few days and couldn't do much here

I went over every resistor and cap in the section I was working on and found an error I made. I had put a .33 cap at C78--which is supposed to be 2200MMF. Translated from the handy chart provided by justradios.-- http://www.justradios.com/uFnFpF.html -- that would be a .002mf cap. I confused it with C80--which is a .33MF cap.

Another thing I noticed was R75, which shows a few 56k resistors. Instead, there were a few 57k resistors in their place on the chassis that started to drift--still within range--but I replaced them anyways.

R5 I had noted had drifted up to 5.1k but I kept it. It's still well within 10%

Dang--I did a quick check of my work before I took off for work--sick--and discovered I put two caps in the wrong place. I shouldn't be working on this right now but I keep having dreams of the CRT lighting up with a full raster and picture I had a real freaky dream two nights ago. I was watching it start up from the back of the set out of the cabinet. The rear of the CRT had this real cool plasma thing happening. A voice was telling me that was the high voltage spreading around in slow motion. Weird...

Feeling better today
I fixed my last problem. I also realized that some of the caps are spec. at 10%. I'm used to re-capping radios with looser cap specs. I'll have to go over the ones I replaced and make sure of the tolerances.

This next section also has a ton of resistors to check. I've been checking them in circuit which has worked pretty well. The ones that read way low are in paralell with inductors. I might pull those or just change them since there's only a few. No opens yet and only a handful of high drifters.

If there's anyone lurking who knows the answer I have a question. Once I get all of the caps and bad resistors changed out, what is the best way to fire this up? Can I start it without the CRT? Without tubes? I have a variac so no problem there.

I get a little apprehensive when its time to do the first power up.
Worry that all my work will go up in a puff of smoke.
This is the part I don't really like and its like a huge hurtle that
takes you over to the other side. But, once there, I feel relieved
that it has been done.

What I do is put in all the tubes and use my 5AXP4 test tube in place of
the sets CRT. Tilt the chassis on its side so I can watch for smoke or signs
of something getting hot. Then connect the AC Power cord to my Variac
and slowly crank the voltage to about 75 volts. Make sure the tubes are lit
and there is no smoke or something obvious wrong. If all is OK at this point,
slowly crank the voltage to full 115vac and see what happens.
I normally have a piece of cardboard that I write down on which control
is Brightness, Contrast, etc. I adjust the volume control and channel
selector and listen for audio. I adjust the brightness looking for raster.

Most times the TV will not show much signs of life - i.e. no audio or video - for various reasons.
Then I turn power off and DISCHARGE THE ANODE.
Next I use my finger feeling components for heat.

The next step is to step back and evaluate the plan of action.

Carl

Thanks Carl,
I don't have a test CRT. Can I use the original?

Yes, you can use the Original.
Your 12" CRT is not as unwieldy as those 16" and 19" tubes.

The advantage of using a 5AXP4 or an 8XP4 test CRT is that 1) it is
small, and 2) that it does not have an ION trap to adjust to get raster.
Nice to be able to immediately see the raster without the ION trap.
Later put the real CRT in for final adjustments.

Still you can get it going with the original CRT.
But, it you find a test CRT relatively cheap, grab it.

Went back to the start of this thread and saw your Porthole on the
back of your truck -- that is indeed a lot of eye candy. You are
going to end up with one nice heirloom.

Carl

What is that knob at the top of the bezel? Mine is missing that, just an empty hole.

That's a fine tuning knob. It somehow tweaks the antenna located on the inside top of the cabinet. I haven't looked closely at how it works but I'd be glad to take some detailed shots of it. It's basicaly a simple knob on a piece of wood dowel.

It adjusts an adjustable capacitor. Supposedly, it was supposed to improve reception. I never saw much difference. Just a gimmick, says I.
Bill Cahill