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Hey guys- Now that the 84 is up and running smooth, I am beginning on restoring a 90 which is in great condition. The question I have might be a rookie one but I didn't run into this yet. The metal containers which house multiple caps in a bakelite mold often contain several different ratings, but the schematic only identifies each as the same ID# without any way to identify which size cap goes to which connection. Am I missing some resource to help me identify these? Thanks forum!
bdi
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The 90 riders contains the drawings of the chassis (like in my case of 2x45) and the position numbers, which then are explained in the respective BOM.
http://www.nostalgiaair.org/PagesByModel...013881.pdf
Example: p5 contains dwg and p7 - BOM. The positions if the tin cans are 25 and 28.
BTW they are tar potted, not backelite.
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bdi, you didn't state which version of the 90 you have.
If it is the one with a single 47 tube (the most common), be sure to read this:
http://www.philcoradio.com/tech/90error.htm
Also see:
http://www.philcorepairbench.com/metalcap.htm
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Ron Ramirez
Ferdinand IN
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thanks guys - I do have a single 47 and found the issue your link points out Ron. It seemedstrange because it all looks original except the ecaps so I figured I'd just redo according to the scheme....thanks for pointing out the error in numbering; this I didn't know. Morzh, I have the info you sent and I see the cap sizes per metal can, but it doesn't show which cap goes to which connection; only says all sizes each particular can has. Since the scheme shows multiple number 24s (for example), I don't know which cap size correlates 2 each specific 24..am I missing something? On the 84 it was easy because all caps in one bakelite block had the same capacitance, but these vary.
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I got it now guys. Just saw the color coded wires for bank 30 - thanks again for your help
Posts: 82
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2 more questions guys...can I replace all bakelite and metal can caps with 630V orange drops in the 90? I saw the original voltage ratings were often 2000V which seems over the top.
And one more...the 30 metal can had 3 caps, however, in addition another metal can was added later and soldered to the chassis with only 1 cap. It attaches to the same terminal on the 28 bakelite as the white wire (0.25mF) from the 30 can. This terminal does not attach to the 28 cap, its only a connection terminal. Being that it was added later, I'm assuming that one cap croaked in the 30 can and the second can was substituting for the dead one. BUT, the original wire and the new cap wire both still attach to the terminal. If I am correct in my assessment, why wouldn't they have disconnected the original dead cap from the terminal? Am I wrong in my assumption? It doesn't appear that 2 caps should be connected end to end.
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Absolutely. 630V is more than adequate.
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Thought so...thanks. I guess I'll just replace the 3 caps in the 30 block and remove the extra block for now. It must have been a replacement for one of the 30 caps. It make no sense that it would be used in conjunction with the other cap in the 30 block.
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You will find that some Orange Drop caps will not physically fit inside the bakelite block housings. Yellow Mylar film capacitors are smaller and will easily fit inside the bakelite block shells.
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Ron Ramirez
Ferdinand IN
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Thanks for the tip Ron - I was wondering about that. Some of them are monsters. I'll have to order some-
As far as the unknown metal cap box, do you think it was just substituting one of the caps in the 30 box? it wired to the same terminal as the white wire coming from the triple cap box.. Are 2 different sized caps ever used in parallel like that, from the same source and both going to ground?
