Garod 15TZ6 adventure

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So, there was a monster, amazing looking combo set on FB marketplace for about two years. Periodically, someone would point it out to me, but I was put off by the size and price.
Initially, $1,000.
Then, $500.
Then, $50 and I broke down and contacted the seller. Really my intention was to just take some photos and size it up.
Even so I dragged my feet.
Here are some photos from the listing. That's a rare 15AP4 CRT in there.






Then, the owner contacted me and said it was free, just please come get it.

I found out later he had check me out and realized I was a serious collector/restored and really wanted me to have it.

I guestimated from the photos that it would fit in my Honda, grabbed a bunch of tools an set out. MY thinking was I'd break it down and muscle the empty cabinet into the car.

Got cold feet on the way and called a friend that lived near the seller. So glad he was able to come over or I never could have managed it.

We broke down the chassis and removed the CRT with no trouble.
She even had amoving dolly and forearm strap that made it easy to get the huge cabinet out.
I do have the missing door pull BTW.






Doh! Were gonna need a bigger boat. Another two inches wider and we would have made it.

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My friend has a bigger SUV and he backed it over. Doh again! His hatch opening is exactly the same size!

At this point we had been the several hours, it was starting the drizzle and the owner had to leave.

I was about to give up when my friend called some guys at his workplace. Turns out their shift was ending and we were able to borrow a pickup.





Safely at home in my garage
Bought my friend dinner, filled the tank on the pickup and gave him $100 cash. So figure about $200 to get it home.


Only damage was a 78 I left on the record player.

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Now here's the deal. I do not have the spare for it, cool though it is. My plan is to restore it and donate to the Early Television Museum in Hilliard, Ohio. I hope to have it done in time for the next convention in early May, 2025.
That's going to be a challenge...

The rebuilt CRT appears to be dead. Possibly an open cathode I can reweld? Otherwise, I'll try to use a 16LP4 or similar.



Some very bad things have happened to this set. I'm guessing from folks plugging it in and turning it on. It is fused, but not well enough apparently.

Caps vented, rectifiers melted and parts charred.

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After reviewing the wiring and removing the crusty line bypass caps, I pulled the rectifiers and power it up. All the tubes and pilot lamps lit up Also, the power supply secondary voltage looked good.



First order of business is to replaced the venter, shorted, oozing electrolytics.


I'm also cleaning as I go. The cadmium plating is in amazing condition under all the filth
Some areas have some sticky goo that comes off easily with lacquer thinner.


Other areas have yellow corrosion (cadmium sulfide?) and I'm using CLR.


They are all isolated on phenolic wafers and a perfect application for "adapt-a-caps". Little PCBS specially designed for just this purpose.

[Electronic M]

Glad you saved it. Stuff like this is why I have a Chevy suburban...Same hauling capacity as a long bed pickup but enclosed and heated so I can pickup 2 full size 8' wide 1960s roundy color TV stereo combos in the worst weather imaginable and get them home without any weather getting to them... It's helped me buy too much but also allows me to bring literal truck loads to swapmeets when I need to sell in volume.

[Tom9589]

Let's hear it for Suburbans. I've owned three starting in 1992. The first one was a Diesel, but that's another story.

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Replacing the five power supply caps was a breeze. Each one is only a single capacitor.


Next, I dove into the separate audio amp.
The 5Y3 was traumatized and several resistors roasted underneath.






The chassis cleaned up beautifully with CLR.




I did a full recap, replaced all the resistors, 5Y3 and missing 6AT6. Also painted the transformer.
I'm happy to report it works very well. Plenty of volume with very little hum or distortion.

[Penthode]

How dead is the CRT? Is there any cathode current at all?

I have found some early CRTs which appear to have an abnormally low cut off voltage. I was deceived by a tube I thought dead actually yielded an acceptable picture.

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No, even at 8.4 volts. Same results with Sencore CR-70.

[Yamamaya42]

I just have to wonder how much power it takes to MELT a 5Y3 like that, and the transformer still OK?
It must be a very large transformer, or you were just very lucky or both?
Cause the transformer in the radio part of my Hoffmen was toasted when the candohm resistor shorted out and took out the 5Y3, the insides of the transformer looked like a charcoal briquette.

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The electrolytic did not measure shorted, but one of the resistors biasing a 6V6 was burned open. Several others left burn marks on the chassis above. Makes me wonder if the output stage was drawing excessive current causing the 5Y3 failure?

Anyway, it's working for now. Also, the reality is that the TV museum does not have sound on its closed-circuit signal course. Reason being they don't want people fooling with blasting sound out of the sets. So we might just leave this amp unplugged once it's on display.

[Electronic M]

Originally Posted by Yamamaya42

I just have to wonder how much power it takes to MELT a 5Y3 like that, and the transformer still OK?
It must be a very large transformer, or you were just very lucky or both?
Cause the transformer in the radio part of my Hoffmen was toasted when the candohm resistor shorted out and took out the 5Y3, the insides of the transformer looked like a charcoal briquette.

It probably depends on how much the unplanned load is and how long it's ran like that. Aboa month ago I was dialing in a 27" Muntz I had fixed a month or two prior to that and it was the first time I'd seen a candohm fail in operation (let out a bunch of smoke and redplated the rectifier). Sixty five percent of the time I see a candohm it's still good and I leave it alone, 30% of the time it died decades ago and someone else replaced it and I leave it alone, and about %5 of the time it failed nobody fixed it and I end up fixing it. But I've never had a working candohm die on me before then. Luckily I caught it in time and nothing else needed to be replaced.

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I splurged on some lovely Spraque Atom axial electrolytics and Ohmite power resistors for the main chassis.


I figured I'd better focus on the charred looking area first.


Just as on the top, the gunk cleans off easily and the metal underneath is in excellent condition.


Not the easiest chassis to work on as some old waxy caps are buried deep.


Back topside for cleaning and tube testing. Only five tubes needed to be replaced.


Still much to do, but I figured this was enough for a full power up test.

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Good news!
The radio fired right up and plays well although the dial scale is a bit off.
I was puzzled by the lack of HV though. A scope revealed no drive signal on the HOT grid.

After more time than I care to admit, I realized that when in radio mode, the TV sweep circuits are disabled.
Now a fluorescent tube glows brightly when placed near the flyback


I had to splice in a conventional anode cap as the original is the goofy snap cap Dumont used.
Woohoo! We have a raster on a little 8XP4 bench CRT!


Recapping continues...

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I'm tackling the vertical sweep circuit next. I expect my lack of height is due to leaky caps.
Unfortunately, there are a couple buried behind the VOT.


I carefully unsoldered the brittle wires and unmounted it. I had to move some peaking coils to get a nut driver on the rear mounting screw.
Ah, that's better.