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McMurdo VI filter caps - Printable Version

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McMurdo VI filter caps - morzh - 02-18-2016

http://www.myvintagetv.com/manuals_and_documents.htm

The link is to the directory, the documents need to be found and clicked upon.

If anyone knows: in say McMurdo VI masterpiece, the power filter caps (listed in parts list, separate document there) 0.5uF 400V and 25uF 500V (listed as 50V but I think it is an error) - were those electrolytics?

RE: McMurdo VI filter caps - Ron Ramirez - 02-18-2016

Mike

Yes, C15A-B-C would have been electrolytics; 25 uF, and probably at least 500V as you said since there is no way they could have been 50 volt and lasted for any length of time! Imagine the size of 25 uF 500 volt paper caps in 1937...Icon_eek

I have not yet begun the restoration of my MP VI, but there are three large electrolytic cans mounted on top of the power supply chassis along with the rectifiers, output tubes, and power transformer.

I do not believe that the 0.5 uF caps would have been electrolytics.

RE: McMurdo VI filter caps - morzh - 02-18-2016

That's what I thought. What was the highest electrolytics' voltage at the time?

RE: McMurdo VI filter caps - Ron Ramirez - 02-18-2016

I honestly don't know.

I will go look in one of my mid-1930s Philco parts catalogs...that won't speak for all manufacturers but will give us an idea...

RE: McMurdo VI filter caps - Ron Ramirez - 02-18-2016

The largest one listed in Philco's 1935 parts catalog is 12 uF, 450 WVDC.

I know Philco used some 475 WVDC electrolytics in the larger 1937-38 models.

(I have a 1937 Philco parts catalog somewhere but do not remember where right now.)

In Philco's 1941 catalog...they listed 8 uF, 500 volt wet electrolytics and up to 12 uF, 500 volt dry (probably paste).

Not knowing what Cornell Dubilier, Mallory, or Aerovox were making at the time...500 WVDC might have been the upper limit.

RE: McMurdo VI filter caps - mikethedruid - 02-18-2016

In the late 30s they made higher voltage electrolytics. I have an old Dumont silverface o-scope. It uses 1000 volt 1 mfd electrolytics in the HV supply for the cathode ray tube.