1950s or '60s vintage Zenith TVs, Need some info

[vortalexfan]

Originally Posted by Electronic M

L would have been the 1964 model year introduced in late 1963 (like car model years are).

The option code leters I don't actually remember which letter goes with which option. My 1959 Zenith had notation on the tube chart that made it obvious what letter was used for UHF and what was used for remote sets, but it's been over a decade since I looked at it and that set is covered in a mountain of junk presently.

The High Fidelity sets always had bass and treble knobs, sets without that option often had a single tone control.

Ok, thanks, I apologize for all these questions I'm trying to familiarize myself with how these old Zenith's work because while my dad's side of the family (specifically his grandparents) were big into Zenith products and thus my dad was as well I'm more familiar with the more modern Zenith sets from the 1980s and 1990s and the Zenith Radios from the 1930s-1960s, but this is my first time working on Zenith TVs from the 1950s and 1960s.

Aside from the old Meck and RCA TVs I've worked on and resurrected successfully I don't have as much experience with Vacuum Tube based TVs as I do Solid State TVs.

[vortalexfan]

OK, so I know that in the early days of FM Stereo Multiplex that often times manufacturers, like Zenith, Magnavox, Motorola etc. would design a radio that was "FM Stereo Compatible" meaning that it had a provision on the radio for an FM Stereo Multiplex Adaptor to be installed by a factory trained serviceman if one so choose to do so later on (specifically the old console stereos from the late 1950s and early 1960s).

I was wondering if that was also the case with the remote controlled TVs from that time period, that they made the TVs with a remote control sub-chassis installed from the factory if one chose to do so (the same was done with FM Stereo Multiplex early on) but then one could also get a TV that was "remote control capable" where the TV was provisioned from the factory so that a remote control sub-chassis could be installed later on by a factory trained serviceman?

If so I wonder if that was the case with my TV?

[Electronic M]

Try holding the end of a lead between a couple pieces of 600 grit sand paper and rubbing then try soldering.

[Tom9589]

Find out where these capacitors are in the schematic. Sams should have the exact value next to the capacitor's symbol. Read Sams footnotes to determine if these capacitors are MF or MMF. Usually, if the value is less than 1, it's in MF. If it is more than 1, it's in MMF.

[vortalexfan]

Originally Posted by Tom9589

Find out where these capacitors are in the schematic. Sams should have the exact value next to the capacitor's symbol. Read Sams footnotes to determine if these capacitors are MF or MMF. Usually, if the value is less than 1, it's in MF. If it is more than 1, it's in MMF.

The odd part is that the Sam's that I have (I bought a PDF download from Sam's) doesn't have the schematic for the main TV Chassis, just the tuner and the remote chassis, nothing for the main TV Chassis though... at least not that I could see.

[old_coot88]

Originally Posted by Tom9589

...Read Sams footnotes to determine if these capacitors are MF or MMF. Usually, if the value is less than 1, it's in MF. If it is more than 1, it's in MMF.

Should oughta read: "if less than .001 mf it's in mmf (micro-microfarad, aka picofarad or pf)

Microfarad or mf (sometimes written mfd) = one millionth of a farad
Micro-microfarad or mmf (sometimes written mmfd or pf) = one millionth of a mf.

Typically values below .001 mf are in mmf/mmfd/pf.

[Tom9589]

And let us not forget the new nomenclature that seems to be in use everywhere today: the nanofarad or nF which is one thousandth of a microfarad.

[vortalexfan]

OK so I figured out what those Bumblebees were, they were .022 μF 400 VDC
and 2 .047 μF 400 VDC capacitors so I ordered some 630 VDC replacements of those capacitors, since they were using the same capacitance values as the modern caps use.

[vortalexfan]

I've already got the two .047 MFD Bumblebee caps replaced in the TV (I actually had a couple of replacement caps laying around of that value that I forgot I had laying around) so now I just need to wait for the rest of my capacitors that I ordered to arrive, which I'll have to work on this more when I get back from my trip.

[vortalexfan]

OK, so I got some more of the paper caps replaced and I went to power on the TV to check to see if I was getting anything on the Screen, and for some reason the set isn't getting any power, the tubes aren't glowing, no static out of the speaker or anything, and I didn't touch anything related to the power supply all I did was replace some of the capacitors (which I took the old ones out and installed them like they went in originally when there was room for the soldering iron to fit without damaging surrounding components.)

Any ideas as to what could be causing this issue? I know it powered on fine before I started replacing components, there is a circuit breaker on the front of the TV, and I know those are notorious for going bad, could that be part of my problem?

[Electronic M]

Circuit breakers can sometimes beco sensitive to mechanical vibration. I'd ohm it out and if necessary wiggle it and or push/pull the button a couple of times before condemning it.

Sometimes power switches will get sticky and or dirty and the contacts will stay open or closed despite the handle being in the opposite state.

Another possibility is if you accidentally shorted the heater wiring there's often a fusible link (piece of magnet wire thinner than the rest of the wiring designed to burn open like a fuse if there's a short).

There's enough that could go wrong that no definite conclusion can be made from available info.
What I typically do in cases like this is pull the chassis and do bench resistance and voltage tests.

[vortalexfan]

Originally Posted by Electronic M

Circuit breakers can sometimes beco sensitive to mechanical vibration. I'd ohm it out and if necessary wiggle it and or push/pull the button a couple of times before condemning it.

Sometimes power switches will get sticky and or dirty and the contacts will stay open or closed despite the handle being in the opposite state.

Another possibility is if you accidentally shorted the heater wiring there's often a fusible link (piece of magnet wire thinner than the rest of the wiring designed to burn open like a fuse if there's a short).

There's enough that could go wrong that no definite conclusion can be made from available info.
What I typically do in cases like this is pull the chassis and do bench resistance and voltage tests.

I monkeyed with the circuit breaker and sure enough it came back to life. But I'm still not getting a picture or raster on the screen, and still no HV.

[Electronic M]

Originally Posted by vortalexfan

I monkeyed with the circuit breaker and sure enough it came back to life. But I'm still not getting a picture or raster on the screen, and still no HV.

Measure the voltage on the grid and screen grid of the horizontal output tube.
The grid will tell you if you're horizontal oscillator lives and the screen can give info on whether there's issues on the flyback side.

The entire horizontal system has to work for there to be HV. It's typically much faster to troubleshoot that system than it is to shotgun parts (though replacement of paper and lytic caps is probably wise).

[vortalexfan]

Originally Posted by Electronic M

Measure the voltage on the grid and screen grid of the horizontal output tube.
The grid will tell you if you're horizontal oscillator lives and the screen can give info on whether there's issues on the flyback side.

The entire horizontal system has to work for there to be HV. It's typically much faster to troubleshoot that system than it is to shotgun parts (though replacement of paper and lytic caps is probably wise).

I'm not sure if it's the vertical or horizontal oscillator that's running but one of them is running for sure because I hear a high pitched whining noise coming through the speaker.

[vortalexfan]

The Flyback Transformer looks like its in good shape yet, it only has one wax drip underneath it inside the HV Cage and that's it.

As far as measuring the Voltages on the Horizontal Output Tube, I thought you weren't supposed to test that, because of a chance of frying your multimeter?