The PHILCO Phorum
Philco 90 restoration - Printable Version

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+--- Thread: Philco 90 restoration (/showthread.php?tid=22832)

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RE: Philco 90 restoration - Bob Andersen - 10-27-2021

That coil was open in both chassis. Same old issue. primary wound over a celluloid insulator that had hardened and warped.
Luckily, the break was easy to find and repair. I did not need to rewind Icon_smile

[Image: https://live.staticflickr.com/65535/51634690659_88ee746f90_c.jpg]

Yep, that fixed it. It must have been barely hanging on and would open up when it got warm.

RE: Philco 90 restoration - radiorich - 10-27-2021

Hello Bob,
That is great news now the radio should work fairly well !
Sincerely Richard

RE: Philco 90 restoration - Bob Andersen - 10-29-2021

I performed a minor surgery on the Philco 20 PP speaker I have so that the field coil is connected to one end of the OT primary rather than the center tap.
[Image: https://live.staticflickr.com/65535/51640295689_4cd9e03df9_c.jpg]

Viola - it works. Sounds a little hollow and dull, but it works fine. I'll use it for now until I can get the 90 speaker field coil repaired.
[Image: https://live.staticflickr.com/65535/51639640821_141fc6032d_c.jpg]

RE: Philco 90 restoration - morzh - 10-29-2021

Unless I missed it - does the field coil work now?

RE: Philco 90 restoration - Bob Andersen - 10-30-2021

I have two speakers. A single ended one for a Philco 90 with an open field coil and missing output transformer.

The one shown above is for a Philco 20 with push-pull 71A driving it. I disconnected the center tap and tied one end of the output transformer to one side of the field coil to make it compatible with my 90.

RE: Philco 90 restoration - radiorich - 10-30-2021

Hello Bob,
good thinking far as the speaker goes !
sincerely Richard

RE: Philco 90 restoration - Arran - 11-02-2021

 I found a cheaper source of magnet wire, can't vouch for the seller of course: https://www.ebay.com/itm/363090262105
Regards
Arran

RE: Philco 90 restoration - Bob Andersen - 11-03-2021

Thanks for the tip. I just placed an order.

I'll try the techniques described in this thread to get the pole piece out and back in.
https://philcoradio.com/phorum/showthread.php?tid=15792

RE: Philco 90 restoration - Bob Andersen - 11-03-2021

Hey, finally found a currently made audio taper 500K pot with a 2" round shaft. 2W rating.

Not exactly cheap at $17.76, but at least there's an option from a decent brand. Shaft can be cut or filed down as needed.

https://www.mouser.com/ProductDetail/CTS-Electronic-Components/287T364R504A21

Also available from Digi-Key for a bit more.
https://www.digikey.com/en/products/detail/cts-electrocomponents/287T364R504A21/11617375

RE: Philco 90 restoration - radiorich - 11-04-2021

Hello bob,
man I wish you were not in a hurry because when i visit my family in dec. i could check my NOS stock of controls .
sincerely Richard

RE: Philco 90 restoration - Bob Andersen - 11-04-2021

Oh, I'm not in any particular hurry. I might very well have one in my stash too. I've seen many radios with a replacement volume control of the wrong value or taper type. It's nice to have options.

RE: Philco 90 restoration - Bob Andersen - 11-06-2021

Magnet wire arrived today. Looks like the real deal. We'll soon find out how well it works.
[Image: https://live.staticflickr.com/65535/51657178382_ccb9d5512d_c.jpg]

RE: Philco 90 restoration - radiorich - 11-06-2021

Hello Bob,
that is great news I do have some but I don't think that gauge thou.
I have a new project to rebuild a huge RCA like 10 tube count chassis with the magic brain .

Sincerely Rich

RE: Philco 90 restoration - OZ4 - 11-06-2021

I wish I had a magic brain. Mine is always thinking the wrong thing.

RE: Philco 90 restoration - Bob Andersen - 11-10-2021

The new volume control has arrived and works very well. Perfect fit too.
It's just temporarily wired in here as I still need to cut the shaft down.
[Image: https://live.staticflickr.com/65535/51668267122_ed78bd9f2f_c.jpg]

I also installed the new arch support. Before gluing I painted with this very flat camo paint. It's a great match for the old dark interior wood.
[Image: https://live.staticflickr.com/65535/51669303818_a3dc82c0c1_c.jpg]

The arch is far stronger now and that's a big load off my mind.
Sorry about the blurry photo. Bad lighting in the basement.
[Image: https://live.staticflickr.com/65535/51669308018_c521f9ef6f_c.jpg]