After years of looking, I finally found one of these black dial Zeniths. Its missing two knobs and has a replacement power transformer. The speaker has many tears but should be easy to repair. I already replaced 4 wax caps but have to order the rest, also, the on off volume control is completely frozen and no matter what I try, it will not budge. If anyone has a working control, I’ll be interested in buying it. Riders says it’s 400,000 ohm and the zenith part number is 63-565, if that helps at all.

Riders says it’s 400 megohm and the zenith part number is 63-565, if that helps at all.
No, it's a 400K ohm pot. Zenith used Roman Numeral M for 1,000 back then. On their schematics if it meant 1,000,000, megohm would be written out as it is for part R3 63-271.


http://www.videokarma.org/attachment.php?attachmentid=198712&stc=1&d=1558298721




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After years of looking, I finally found one of these black dial Zeniths. Its missing two knobs and has a replacement power transformer. The speaker has many tears but should be easy to repair. I already replaced 4 wax caps but have to order the rest, also, the on off volume control is completely frozen and no matter what I try, it will not budge. If anyone has a working control, I’ll be interested in buying it. Riders says it’s 400 megohm and the zenith part number is 63-565, if that helps at all.
I think I have a scrap chassis like that.
I'll check later today and if so, I'll check the condition and PM you. The power transformer was replaced in the chassis as well.
Dave.

Nice looking radio. Probably sounds good too.

I think I have a scrap chassis like that.
I'll check later today and if so, I'll check the condition and PM you. The power transformer was replaced in the chassis as well.
Dave.

Ok. That sounds good

Ok. That sounds good

The chassis I have had a universal replacement control in it.
The control has a 2&3/16" shaft length. It's a 500K pot with a spst switch so it should be close.
See if you can shoot some contact cleaner in your pot to loosen the binding.
It looks like your chassis was stored in a damp area, where the control seized because of unlike metals used in the assembly.
You might have to dissemble the control. Try that first! :scratch2:

No, it's a 400K ohm pot. Zenith used Roman Numeral M for 1,000 back then. On their schematics if it meant 1,000,000, megohm would be written out as it is for part R3 63-271.


http://www.videokarma.org/attachment.php?attachmentid=198712&stc=1&d=1558298721




.


Never understood where they got the idea that a K should represent 1,000 when M is 1,000 in Roman Numerals (so really the way Zenith did their schematics back then made perfectly good sense in my opinion).

Never understood where they got the idea that a K should represent 1,000 when M is 1,000 in Roman Numerals (so really the way Zenith did their schematics back then made perfectly good sense in my opinion).

https://en.wikipedia.org/wiki/Metric_prefix

http://www.videokarma.org/attachment.php?attachmentid=198723&stc=1&d=1558408916

After years of looking, I finally found one of these black dial Zeniths. Its missing two knobs and has a replacement power transformer. The speaker has many tears but should be easy to repair. I already replaced 4 wax caps but have to order the rest, also, the on off volume control is completely frozen and no matter what I try, it will not budge. If anyone has a working control, I’ll be interested in buying it. Riders says it’s 400,000 ohm and the zenith part number is 63-565, if that helps at all.
You are going to have to remove the pot anyway so you can try to loosen the binding. From the looks of the shaft, it looks like a universal replacement, as well.
That model must've been a real problem with power transformers and volume controls. :D

You are going to have to remove the pot anyway so you can try to loosen the binding. From the looks of the shaft, it looks like a universal replacement, as well.
That model must've been a real problem with power transformers and volume controls. :D

Sure looks like it. I’m getting a control from a local friend.

https://en.wikipedia.org/wiki/Metric_prefix

http://www.videokarma.org/attachment.php?attachmentid=198723&stc=1&d=1558408916

So in other words its a reference to the metric system of measurement...:thumbsdn:

Of course they would do that, anything to try and get us Americans off the Imperial Measurement System and into Metric.

So in other words its a reference to the metric system of measurement...:thumbsdn:

Of course they would do that, anything to try and get us Americans off the Imperial Measurement System and into Metric.

The US government was planning for the Metric conversion in the later 70's and the early 80's.
The firm I worked at, bought a new machining center built like 10 miles away from the plant, that was all Metric. I, inquired as to the reason and the service rep said that the US government bought a lot of their machinery. :scratch2:
When this Metric conversion died down, the firm bought another machine three years later, it was all SAE. :thmbsp: