Help me identify this Zenith?

[Electronic M]

You're welcome.
A few thoughts. You can use the horizontal output of one set to drive another (the 1077 is basically that only it has a second output tube dedicated to the task) as long as there's no hot chassis action going on and you ground the chassis together. A monochrome set will be a little weak to drive a color to normal levels, but honestly so is a 1077 (boost and sweep width won't be full on).

Monochrome yokes are fairly universal (neck size and deflection can be issues) If you have anything that fits over the 1077 neck it might work.

[Jon1967us]

Wow nice set

[DavGoodlin]

This is a beyond-interesting thread for sure, I hope you find a schematic. Design changes that are fascinating, starting with the power supply.

The VDR in the 6HV5 circuit should be replaced if you can. That one item is holding me up on all my post-66 tube Zenith color sets, to make sure HV won't go too high. The 66 and earlier Zeniths used a 6BK4 shunt regulator tube with no VDR.

I still have the 12B14C52 my parents bought and the first time I saw the picture of this import model without a Hue knob, I was looking daily for updates on this post. Thank you Alan!

[AlanInSitges]

Glad you're enjoying it, Dave! I'll fill in a bit more information you and others might find interesting. Getting back into TVs over here has been a fascinating experience. So much to learn about the way things worked and were built in Europe that I had never been exposed to, and the surprisingly big role some American companies played in the market here. I think the American stuff was likely political in nature. Spain was still a dictatorship until 1975, and I have a feeling that their relative pariah status enabled the US government to help out by setting up American companies here. I don't know for sure that's the case, and the few conversations I've tried to have aren't really something people want to discuss a whole lot.

Anyway.

So, neither my Zenith, nor the others you have seen, were export models. They were built in a Zenith factory right here in Barcelona.



Zenith Radio Corporation set up a joint venture here, bankrolled a factory, and started building sets based on American models with a mix of imported American and European-sourced parts. Pre color, the sets were nearly identical to their US counterparts. I have a couple of boat anchor 12" B&W sets that, aside from an autoformer and switch to select the mains voltage, have identical chassis in every way that I can see to an American set. I have the Sams for a 13M15 chassis, mine is a 13X15, and all the parts - tubes, electrolytics, are American, and all the values of components in the sweep circuits, etc., are unchanged. The text on the back is in Spanish, saying it was built here, and the VHF knob has those dorky European channels like E on it.




I also have a Philco set based on the American 14J41 ("The Townhouse") chassis. As opposed to setting up their own factory, Philco contracted with a local company to produce sets based on American designs using a mix of parts. My set has all original markings - chassis number, cabinet back with the notice in English about complying with FCC regulations, everything, but the luxury tax stamp on the chassis indicates it was built by Iberia Radio, who sold sets under their own brand and produced for a bunch of others - I have seen Emerson and Westinghouse sets built by them using European designs. My Philco has a different power transformer than the American one, and the power supply has been heavily adapted to work here. The chassis itself, PCBs, and tubes are all identical to the Sams, but almost all the passive components were locally sourced, with Bianchi electrolytics that are all still good. Lots of bodges, capacitors tacked under the PCB, etc., and the tuners are completely different than what's in the Sams. I haven't ever seen a Zenith ad in Spain, but Philco were ALL OVER IT, with heavy print campaigns and they even got Miss America to come over here and pose for a picture with one of their fancy Yankee TV sets. They leaned into the fact that they produced (I think) a camera tube used on one of the moon missions to claim that the US government trusted them for the new era of Philco space exploration. No comment.


I have tons of pictures of the insides of these weird-o sets if anyone is interested, along with a GE built by Philips.

Back to the Zenith at hand. I'm taking the yoke off of an old Philips I have and will see if I can get the 1077 going. That's the plan for today.

[AlanInSitges]

Hey made some progress today. I put the HV rectifier back in its place, and removed, cleaned pins, sockets, and re-seated the sweep tubes, and powered it up again, with a meter across C146. It rose to an indicated 460V (so adding the 400V B+, that would give 860V, just about the 875V Boost in the Sams) and I heard the HV come up for about 2 seconds, then the Boost started dropping down to an indicated 160V, again referenced to B+, where it pretty much stayed for a few minutes.

Click to embiggen:


I repeated the test a couple of times more and the HV never returned, and the Boost never rose above that indicated 160V. I'm going to let the set cool down completely and try again.

This is the behavior I saw on first power-up, and so I think the completely dead HV was an anomaly caused by removing the tubes and moving things around. Now that I know it can make HV I don't have to hassle with putting a yoke in my 1077, and can hopefully go on to troubleshoot the actual problem.

Another thing I noticed: the 400V B+ is low, about 360V. This 400V source goes only to the Boost filter, and is derived from the main B+ that goes through the vertical centering control. I'm not sure why that is, that control is also connected inline with the yoke and it seems to me there would be an awful lot of noise on that 400V line, no? Anyway unless the source of the 400V is pertinent to the problem at hand I'd prefer not to worry about the why for right now. I'm going to connect another meter to the 400V source at the cold power-up and see if it's normal before the boost starts dropping, that may help me figure out if this is due to excessive current draw or something else.

This set has two varistors, one off the grid of the HO tube and the other between Boost and the grid of the HV reg. Is it possible one of these could develop a thermal intermittent causing...something? My theory right now is that the dropping boost is a symptom of whatever is really going on, and that low B+ is probably a clue. I'm reading the articles I've found in old Photofact Reporters about this circuit but still don't have my head around it.

Anyway thanks again for the all the suggestions, help and encouragement. As a thank you, here is a picture of the PAL DuraModule where the 6GH8 ought to be. I'm wondering if this is "real" PAL or some kind of reverse-engineered faux-PAL.

[zeno]

Interesting stuff. A few notes:
Modelo B4519W KT Following US convention
B is model year "B line"
45 means 23" US size. ( 19" is 40, 25" is 47 )
19 is a consecutive ## the higher the better.
W is walnut ( X is white, M maple, P pecan etc )
KT must mean kit, never seen that.
Chassis numbering UP TO B line. example 4B25Z19
4 is tube count ( not inc CRT)
B is B line
The rest I do not know
Set is one step below the 4 tube hybrid that came out the same year.
Color module takes the place of our 9-27 but looks different. If your
manual shows a 6GH8 its probably the wrong one.

Check the ground lugs for the terminal strips. They can crack & cause ints.
Check the damper & HV reg against the tube chart. You need the right
pair for it to regulate. I dont remember why.

73 Zeno
LFOD !

[Electronic M]

Some additional notes to Zeno's. I believe the hybrid chassis numbers up to B line included both tube count and transistor count. For example my 15Y6C15 IIRC has 15 tubes and 6 transistors.

Zenith didn't want the set to work without the HV regulator installed so they wired the damper and reg heaters in series. However there were 2 different heater current HV regs and 2 different heater current dampers....If you didn't use a pair with matched heater current one tube wouldn't warm up properly and the other would have excessive heater voltage...I don't know how it effected the HV but it obviously wouldn't be good.

Your boost is actually 820 since the 400V rail is only measuring 360V.

IIRC it's possible to run one of these sets without the HV regulator if you use clip leads to connect only the heater of the regulator. HV will be as high as it can be that way but if you need a go/no-go on the flyback that is a way to get it.
I have a 20CC50 that years ago I wanted to fix but didn't have the IIRC one and only HV reg it needed. I think I briefly ran it like that to make sure the fly was OK, then I figured out I could add or swap a wire for a cathode, plate or grid to make a 6HV5 work in it.

[AlanInSitges]

Well, my set has 11 tubes so who knows! I've also found a few other discrepancies, the Sams shows a 6Z10 for audio detector and audio output, but my set just has a 6BQ5. Dunno what's doing the detecting...

I have found a guy here who thinks he has the original service manual for that set, he's going to look for it this weekend.

Meanwhile, I did some more tests. It's not just the 400V that's low, it's all the B+, including the main 405V line. With a cold startup it goes up to about 400V and then drops quickly to around 350V once the various circuits start working.

So in the meantime my big question: is the low B+ a symptom of the problem with the HV? Or is the HV a symptom of a problem with the B+? Or are they likely two unrelated problems and that low B+ may not have anything to do with the lack of HV? Which to tackle first?

I've checked that none of the filters are getting hot, and there's a big 18W dropping resistor in the power supply that isn't getting any hotter than I would expect it to.

[Electronic M]

Both systems are capable of effecting the performance of each other.

I would check the horizontal output cathode current. If it is excessive it could be lugging down the B+.... Likewise if the H output tube or damper is removed and the horizontal output stops drawing B+ current entirely then the B+ should increase beyond it's nominal design voltage.

The Horizontal output is typically the largest current draw on the B+ so B+ won't be normal if H output current isn't reasonably close to normal.

HV can also be reduced (though you should still get raster) by low B+. If you ever run a set on a Variac and observe reduced HV and usually either blooming or shrunken raster you can see that in action.

[AlanInSitges]

I tracked down the schematic! It's in the Spanish equivalent of Riders, looks like. Anyway the book is on its way. The chassis number doesn't match but the guys on the local forum assure me this is it, in fact it's all the color chassis Zenith made here.




Regardless I have some time today I'm going to dedicate to tracking down what Tom said above.

[nasadowsk]

As an aside, the GEE logo was classic GE minimal effort

[AlanInSitges]

As an aside to that aside, GEE was at least partly owned by the state back then.

The choice of color system was a pretty big deal politically because it allowed the main players, USA, Germany, France, a degree of influence over technical policy in the countries that chose their system. It was almost always a political choice rather than a technical one.

Spain had decided on SECAM as their color system in the mid 1960s after a few years of trialing PAL, SECAM and NTSC. Once the decision had been announced, nothing happened and the people were asking why there was none of this promised color on the single (state-controlled) channel that existed at the time.

After three years of non-action, the Ministry of Culture said oops our bad, we meant PAL. At the same time, but totally unrelated, the German government handed over 200 million Deutsch Marks to the Spanish government as a loan (wink wink). The French were livid. As a consolation prize, Spain "gave" GEE to Thomson. All the press I can find from the era just say things like "gave" or that they "received" GEE. It's not super clear if it was just a gift or they paid something for it. Anyway, French Thomson wound up with half-ish-Spanish GEE, who didn't make anything* and had been selling TV sets based on a Dutch design built in a factory in Barcelona, as the consolation prize after Spain chose a German color system. Europe!

And yeah, that logo is not at all surprising coming from GE and Spain.



*Evidently they made industrial motors for trains, and still do, but no consumer electronics, those were all farmed out to the lowest bidder.

[Electronic M]

Originally Posted by AlanInSitges

As an aside to that aside, GEE was at least partly owned by the state back then.

The choice of color system was a pretty big deal politically because it allowed the main players, USA, Germany, France, a degree of influence over technical policy in the countries that chose their system. It was almost always a political choice rather than a technical one.

Spain had decided on SECAM as their color system in the mid 1960s after a few years of trialing PAL, SECAM and NTSC. Once the decision had been announced, nothing happened and the people were asking why there was none of this promised color on the single (state-controlled) channel that existed at the time.

After three years of non-action, the Ministry of Culture said oops our bad, we meant PAL. At the same time, but totally unrelated, the German government handed over 200 million Deutsch Marks to the Spanish government as a loan (wink wink). The French were livid. As a consolation prize, Spain "gave" GEE to Thomson. All the press I can find from the era just say things like "gave" or that they "received" GEE. It's not super clear if it was just a gift or they paid something for it. Anyway, French Thomson wound up with half-ish-Spanish GEE, who didn't make anything* and had been selling TV sets based on a Dutch design built in a factory in Barcelona, as the consolation prize after Spain chose a German color system. Europe!

And yeah, that logo is not at all surprising coming from GE and Spain.



*Evidently they made industrial motors for trains, and still do, but no consumer electronics, those were all farmed out to the lowest bidder.

Fascinating. I have to wonder if this helped contribute to Thompson buying American GE/RCAs consumer electronics division in the late 80s early 90s...We already have a foot in the door of owning them let's just buy whole shebang since twiddle dee is selling his company piece meal.

[nasadowsk]

Europe seems to have been almost as dysfunctional as the US was back then! Interestingly, Spain trialed French nuclear technology (CO2 cooling, already obsolete) and US designs (including the only one loop PWR Westinghouse ever sold). I don’t know if Westinghouse had any other involvement over there (they sure did in France, Framatome was born out of Westinghouse’s four loop reactor)

Spanish electric locomotives are 3,000 volt DC power. GE in the US (and South America) was a big proponent of 3,000 volt power. A few Spanish electrics in the early days were built by Alco in the US, who had close ties to GE.

None of this has much to do with TV, but might be interesting to someone…

[AlanInSitges]

Oh, I think most history is interesting! I have wondered about the Thomson/GE connection too...

Funnily enough, Westinghouse operated here in the 60s and 70s selling the exact same rebadged Philips/Miniwatt-made TVs that GEE did. I have one of the GEEs but the Westinghouse are harder to come by.