Another Zenith "bugeye" restoration
 

Yes, I'm working on another bugeye set. This time it's a 16Z25 chassis and a 14XP4A CRT.

http://farm9.staticflickr.com/8501/8...38c65bda_c.jpg

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There are some odd old repairs. Like two fusible resistors where only one is needed.
Also found a ceramic also in the AGC/IF shorted to ground and resistor added in parallel with the HOT bias resistor. I guess someone was trying to improve the brightness or contrast ?

http://farm9.staticflickr.com/8072/8...a99c9220_c.jpg


I restored the circuits to their original values and wiring using a Sams and another, restored 16Z25 for a reference.

After a quick recap, I bypassed the CRT filament with a power resistor, popped the HOT cap off and powered it up. B+ seems fine, but I only get sound for a few seconds before it cuts out.
http://farm9.staticflickr.com/8080/8...1519091c_c.jpg

I figured it's and AGC issue and tried adjusting the AGC control but nothing happened. I unmounted it for a closer inspection and found it's shot just like in the other bugeye I'm working on.
http://farm9.staticflickr.com/8352/8...771e25c4_c.jpg

I temporarily tacked in a new control, but it made little difference.
Next, I did a resistance check on the tuner and IF and sound tubes and compared to the table in Sams. The only odd values were on pin1 of the RF tube and pin1 of the 1st IF tube. Both are about 40% high and part of the AGC buss. I'll start check the associated resistors.

It took a while, but eventually, I tracked the problem down to this 3.3M resistor that had gone open. I took a while because I tried measuring it in circuit and by coincidence it measured about 3.3M across it.
After exhausting other possible bad resistors, I came back to this one and disconnected one end. Sure enough - infinite resistance. That got me good sound, now to try for some video.
http://farm9.staticflickr.com/8351/8...c9ea4e0c_c.jpg

First though I had to replace a busted brightness pot :o
http://farm9.staticflickr.com/8488/8...6416a56c_c.jpg

Then using an 8XP4 test CRT only produced a faint, ghostly image.
http://farm9.staticflickr.com/8200/8...966ec157_c.jpg

Next I'll try the 14XP4.

Regarding the CRT heater, I just used to use a brightener to complete the circuit. I would also try the brightener on the test CRT to compensate for the heater current difference. It might be a little more voltage for the test CRT, but it's only for a short time.

Great idea! I'll have to remember that.

Hi, you seem to get getting through these Zeniths at a good pace. At least servicing and access is easy. It seems those pots are the biggest headache with that chassis. I've struck that phantom resistor syndrome before where across the open resistor it reads roughly the same... But having the identical resistance would have been a pain though...:yes: These things are sent to try us....:scratch2:.. This chassis looks like its coming back to life :) Cheers Glen

Yes, these are much easier to work on than the Predictas. Only took a couple hours to recap :)

I remounted the 14XP4 and added a little aluminum foil to bridge an area where the aquadag had worn off,
http://farm9.staticflickr.com/8223/8...c87696a0_c.jpg

I remembered to position the width sleeve correctly this time ;)
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After some ion trap magnet fiddling, I got an image, but the vertical hold is nonexistent. Time to hunt for more bad controls, resistors or tubes.
http://farm9.staticflickr.com/8349/8...06d0e39d_c.jpg

Do both of those sets belong to the same owner?
They were both in really rough condition.
I had a set like that only 50 years ago. Mine had the handle that folded below the front bezzle. The set worked perfect and had UHF.

Yes, and a 3rd as well that was in the best condition of the three. I got that one running without much trouble.

As for this set, I found a fried resistor in the vertical circuit. I think it fried because I didn't install the focus strap correctly and put 245V across it.
http://farm9.staticflickr.com/8356/8...42e6b277_c.jpg

I figured the focus (pin 6) could connect to either pin 2 or pin 10 (whichever gave the best focus) and had it going to pin 2.

However, the schematic shows it going to pin 10.
http://farm9.staticflickr.com/8084/8...265c154b_c.jpg

That got the vertical working better, but it was taking a long time for the oscillator to startup. I went to swap out the 8CM7 and discovered I had installed a 6CM7 by mistake :o
http://farm9.staticflickr.com/8218/8...07f0c939_c.jpg

It's working much better now :D
http://farm9.staticflickr.com/8058/8...b6bbd987_c.jpg

I have a set like this that I may get around to fixing one say soon it needs filter capacitors that I never got to changing.

Great picture now!

I picked up a B&K 415 a couple months ago that was barely if ever used. This seemed like a good opportunity to finally fire it up.
http://farm9.staticflickr.com/8222/8...1a500e04_z.jpg http://farm9.staticflickr.com/8495/8...290984e5_z.jpg

It works :)
http://farm9.staticflickr.com/8072/8...f79e86c6_z.jpg

Zenith aids alignment by making all the key connection points readily accessible. After a bit of twiddling coils, I got the response close to what was shown in Sams.
http://farm9.staticflickr.com/8362/8...eccf76e0_z.jpg

The picture is noticeably sharper and sound clearer :) Here it is hooked up to my modified Sencore VA62.
http://farm9.staticflickr.com/8216/8...13f9b78c_z.jpg

Here are the multi-burst and crosshatch patterns. The two rightmost bars in the multi-burst are 4.0 and 4.5 MHz. That's beyond the bandwidth of this B&W set. I'm curious to see how they come through in a pre-color set like the 630TS.
http://farm9.staticflickr.com/8494/8...3b74fee4_z.jpg http://farm9.staticflickr.com/8214/8...a910cd6c_z.jpg

Here's some shots of MeTV. The closing credits for Combat! make a good test pattern too :)
http://farm9.staticflickr.com/8497/8...9f89c76c_z.jpg http://farm9.staticflickr.com/8073/8...6ee08e98_z.jpg

All that's left now is to put it back together :yes:

That Pic looks great! Just how off would you say that the IF Alignment was?

The video response was lopsided and shifted about 0.5 MHz when I started. Also the audio was a bit weak and had a buzz.

The amount of technical know-how, & the ability to ferret out intractible problems by the membership here NEVER fails to AMAZE me..You guys are WIZARDS...

Thanks! I used a little Meguires wax on the cabinet and cleaned the safety glass. Now, all it needs is a couple metallic knob inserts for the front controls and a few more of these little knobs for the top controls. I'll dig my big box o' knobs out the the attic and might get lucky.
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That thing is COOL! My Grandma had one of those. Maybe one of these days one will find me and I can restore it. Great restoration....it looks almost like new

Those little knobs are always missing on the Zeniths, we need to learn how to cast some. I need them too.

Casting a knob like these with a hollow shaft might be tricky since you'll probably need a two part mold.
I was just about to give up when I found a few at the bottom of my last box :) Wish I had tried that one first!
http://farm9.staticflickr.com/8215/8...e2acf923_c.jpg

Far out and I thought I had a big collection of knobs....:D Your 'stash' exceeds mine by 100%! :yes: Always the way huh, finding what you need right at the bottom :smoke:
Wow, this Zenith looks really nice too, great job. :) Its currently 8:45pm in the evening here and still 28 Degrees/82.4 Fahrenheit outside. Today has been the hottest day in our city of Wellington for the 2nd time in 30 years! Its pretty warm.... Cheers.

I'm finally finishing off the last of my buddies three bugeye sets. What was holding me up was the missing speaker bracket. So I decided to fabricate a copy based on another set.

First, I cut out a piece of sheet metal using a dremel tool.
http://farm9.staticflickr.com/8542/8...dc661729b4.jpg http://farm9.staticflickr.com/8394/8...9b4b9d0361.jpg

Then, I drilled some holes with a nice new titanium drill bit. So much nicer than the crappy ones that came with my drill :yes:

Next, I bent over one edge using pliers and a little hammering. Finally, I used a pop rivet to join it to the speaker and mounted it in the chassis using some insulating washers:)

I'll try to get it all back together later tonight.
http://farm9.staticflickr.com/8403/8...ace4d0ba0b.jpg http://farm9.staticflickr.com/8380/8...c0cd470a94.jpg

The knob brights fell out some time ago but luckily we still have them. I polished them up with Simichrome and used contact cement to glue them back on.
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I'm calling this project done :)
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Just curious. I have a Z1817 or Z1819 with the 15Z31 chassis. The knobs are further up on the cabinet and without the bulges on the side. Would that be considered a "Bugeye" or not.

I think so. Here are all three of my friends "bugeye" sets before he comes and gets them.

It was surprisingly hard to take a decent photo with them all turned on. They looked fine to my eyes, but one or two would often be washed out in the photo. Adjusting the brightness controls did the trick even though they looked terrible to me.

http://farm9.staticflickr.com/8120/8...f3be2454_c.jpg

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Long time ago I once worked for a small company that made video image to x-ray film hard copy cameras. We had to set the brightness and contrast of the CRT displays (we had them inside a metal box, aimed at a lens system that in turn exposed the x-ray film) adjusted so the contrast would look good on the film but looking at the CRTs directly the images did look washed out.

I can see why those small knobs on top of those sets become missing. They probably get broken off when the sets sit in storage.

I have version with the "eyes" centered on the cabinet sides. The knobs also look more like eyeballs (rather than gears). I think mine is the earliest version.

How does Simichrome compare to Brasso? I think I've seen you use Brasso as the last step in ploishing out scratches on bakelite but I don't recall you using it on metal.

Very nice job Bob. You've given me, and I'm sure many others, great tips. Your making me want to go pick-up a blue and white version of the bug-eye that a friend has for sale! It's woking and complete, but I would have to try to make or find the brass inserts for the knobs. They're missing.

Simichrome is much finer and doesn't have ammonia in it like Brasso does. It also has some oil that leaves a bit of a protective barrier. I use Simichrome on metal all the time and it's fantastic. It works fairly well on bakelite too. I wouldn't use Brasso as the last step on bakelite unless you can find the old stuff in a metal can which is a finer grit or so I've heard.

Thanks. They're not exactly my favorite sets to work on but they do produce a nice bright picture. These sets are missing an insert or two as well :(

I had the same model. It was a 17". It was a year earlier model. I don't think they built a smaller model that year.
I had one of those sets the Bob just restored. It had the better AGC circuit in it. That was only 51 years ago. I sold it cause I needed the money bad.
Mine was only 5 years old when I had it. It had the handle that folded under the screen. Of course, mine had a UHF tuner, as well. :thmbsp:

I thought I remembered seeing a site where someone made his own replacement brass brights, and here it is. A bit complex, requiring a lathe, but worth a look.

http://www.vintage-radio.net/forum/s...ad.php?t=26740

I love it! Beautiful! They look like brand new.
Question: In the picture of all 3 sets running, the picture on blue set is out of sync with the other two...How? If they were digital sets I could understand this but analog sets fed from a common source can't do that....can they?

Very cool! I wish I had the equipment and skills to do something similar.

I've been waiting for someone to point that out :) I could only find a two way splitter so the two sets on the right are being fed from cable while the set on the left is over the air. The delay is a second or two between them.

You can watch a video where I explain the setup and show them playing here: http://youtu.be/PopSArvEHZU

If it was my set, I would clean off the glue residue and spray paint the centers with bright brass spray paint. It would look better than just the bare knobs.
Then, if you get the proper inlays, it can be easily undone. :yes:

Two of the small knobs on the middle set are sticking up a bit far. Is this supposed to be that way? Beautiful sets, though. Makes me want to get one. I love metal cased Zeniths.

I thought so too.
They're made of soft plastic and can be trimmed shorter.
You guys sure are picky, picky. :D

I have no idea. I figure the owner of the sets can swap them around or trim them as needed.