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Zenith 12H090
#1

Hi folks,

While we are away at our other place, I am taking the opportunity to grab the chassis from this set to restore back at the radio hospital.

It was given to us by friends in LA and seems to have been owned from new. I have all the manuals and literature, including pages of labels for the preset buttons.

Quite a challenge to get the working bits out of the cabinet, and immediately, the crumbly rubber wire rears its ugly head.

Under the tuner, there is a lot of recapping to do and it appears difficult to reach the parts in many places.

Mrs H loves this set, and would like it to run again for when we are here. I am starting his thread to record progress once the RCA is off the bench.

Schematic and service info has already been located.

Cheers

Ed

I don't hold with furniture that talks.
#2

Yes, 1940-s Zeniths have rubber wiring. Lots of it is white (beige?) and is still pliable. But red, green, black and blue are all dried up. Most of it is filaments power and some are the RF coils connections.
I went through that when restoring the Spinet. But it all is easily accessible.
Good luck, it should be a good sounding radio.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#3

That describes it well enough Icon_smile

I was at least able to clean up the tuning drive while inspecting the radio portion of the chassis. This is laden with paper caps in some awkward looking locations.Time and patience required. With it so original and unmolested, it is worthy of restuffing.

Cheers,

Ed

I don't hold with furniture that talks.
#4

Oh yeah...laden is the word.
Like here.

http://www.philcoradio.com/phorum/showth...039&page=2

Icon_smile

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#5

Here is a selection of pictures, . The cap situation in the power supply/audio output chassis doesn't look too desperate, in contrast to the tuner... at least the whole thing is original and unmolested.

   

   

   

   

I don't hold with furniture that talks.
#6

That's about as fresh as they come. I like it when the undersides are untouched like that. The wires look quite nice, also. Are you keeping those "as they are?"
#7

http://www.philcoradio.com/phorum/showth...039&page=5

You will see the pics here.
Some wires are kept. But many had to go.

PS. Very clean looking underchassis. If you could hollow that capacitor without destroying it (it is pretty much a paper shell and lots of very hard epoxy to take out) it'd be great but then it might be a bit onerous.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#8

Oh, those CAN be hollowed out. Have done several, including a few in the '36 jukebox that I rejuvenated not too awful long ago. It takes ALOT of time, drill bits, sweat, gloves, consternation and determination to make it happen.  Icon_twisted Yes. Yes, they can be hollowed out while saving the shell. If I recollect, a Zenith I did awhile back had what looked to be CONCRETE in it. It was that hard. But I got it all out, and the tube looked none the worse for wear.  Icon_biggrin
#9

Which capacitors have the epoxy in them, they look like paper and wax to me? What I do with those is melt the wax out in an old toaster oven, at about 200 degrees, then the old caps just slip right out of the tube. I've surprised that this set has rubber wire, it looks post war to me, then again they were using whatever they could get at the time thanks to materials shortages. Get rid of those sand resistors, they are garbage, the ends of the resistive wire corrode and they go open circuit.
 Speaking of drilling an old cap out, that's one way to re-stuff a bumblebee or Sangamo Little Chief cap, cut one end off, drill out the contents with a bit of the right size, then remove the leads from the ends with a smaller bit.
Regards
Arran
#10

Thanks folks!

For the cap, I think the epoxy fill is inside the large tubular electrolytic.

As yet, I'm undecided about going to the lengths of restuffing the paper caps. There are also plenty of resistors to check - if they need to be replaced, then original appearance is compromised.

What say the experts?

Cheers

Ed

I don't hold with furniture that talks.
#11

All I know is that the several caps that I drilled out weren't just "epoxy" that melted out with a little heat. I about roasted one of them as a test. Did absolutely NOTHING to it but getting it hot. And I swear, whatever a couple of those caps were filled with out of the Zenith that I did looked exactly  like concrete. And was just as hard. If those slide right out, send me the video. I'd like to see that one...
P.S. I'd re-stuff
#12

It may have been some sort of cement product, that was what was used in the ends of those ceramic tube type paper caps, maybe a masonry drill bit to break it up rather then a regular twist bit? How much of the can is filled with the stuff? Maybe you could cut the can with a pipe cutter further up and remove and replace the old caps that way?
Regards
Arran
#13

Therein lies the rub. Yes, I absolutely HAD to use a masonry bit, along with using the "hammer" setting on the drill. I believe I piloted a hole with a sharp metal bit on the inner metal sections, and tried to remove as much of that stuff as I could, You only get so far with that. The metal twists and gets mixed in with the "concrete". (I say concrete, because I think it was). Then you crack out the 'ol mason bit, then you have a go at that. You only get so far there, because of the metal dulling out the mason bit. Then you put it on hammer mode, and then gently give it a whirl. You only go so far again. Then it's back to the metal bit, which gets dulled out by the concrete. rinse, lather, repeat. Make sure you have plenty of drill bits and lots of "mettle" on hand. Oh and specific gloves soas you can feel the pressures exerted. Haven't found an effective way to really clamp it without harming the cardboard tube, so holding (for me, anyway) is best. Some seemed slightly less difficult to gut than others, but you have to take great care, as the muck runs all the way through it, and once you get about half-way, it can get pretty intense, as the tube can start becoming *thinish*, as sometimes the concrete is a little stuck to the inside wall. Yeah, I've run across a few like this, especially in Zeniths, and also in a 1936 Mills jukebox, to be precise. Good luck to you, should you choose to accept this challenge!
#14

It's about 1/2" of that stuff on each side.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
#15

...if these caps are so hard to get into, it makes you wonder how they could go bad  Icon_lol

I suppose I'll take a look, but there is plenty of "employment" elsewhere in the radio chassis.

I don't hold with furniture that talks.




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