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Philco 36 660X - Printable Version

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Philco 36 660X - MICHAEL CHAMBERIS - 11-01-2025

Restoring a 36 660X, I'm currently recapping and repairing prior work. Bakelite condenser 88 was partially unwired, made progress with schematic but was hoping someone with same chassis could take a detailed pic for me. Caps were replaced before and a IF transformer was replaced, found wiring issues all through out the chassis. Any help or sugestions are appreciated.

RE: Philco 36 660X - MrFixr55 - 11-02-2025

Hi Michael,

First off, welcome to the Philco Phorum, a phamily phriendly phorum of pholks phull of phine Philco phacts and phun! (See a pattern here?)

Do take some time to read our rules and regulations and "What not to post". We really want everyone to have the best, most positive experience here. Please surf through the Phorum to see how the various topics are organized. While you are at it, don't forget to stop by "Old Ron's Bar and Grill" for a virtual burger and brew, and to shoot the breeze!

We are happy to help. Family Friendly means that we don't curse or insult people for lack of knowledge (or any other reason), so please do not hesitate to ask questions. There are no dumb questions, as all of us started sometime. (For me, it was 65 years ago, so I learned a lot and forgot a lot.) Keep posting and let us know how you are making out.

Now to your radio:

Attached below is a link to a schematic and under chassis parts diagram for the Model 660:
https://philcoradio.com/library/download/service%20info/wiring%20diagrams/vol1/split/Part90-Philco%20Wiring%20Diagrams%20Vol.%201.pdf

2 things that I see from your pictures:

You have questions about a Bakelite block that you have circled and described as #88. This is actually Block #43, a 0.05uF capacitor which acts as a "filter" for the AVC voltage. All looks good here. The center tab on block 43 is merely a terminal. there should be no internal connection unless someone disassembled and restuffed this block, adding the 1.0uF capacitor shown on the schematic if that black wire actually does pass through the rivet holding the middle terminal if the block in place. Capacitor block 88 is where the number 88 are written. Wiring here looks correct when compared to the schematic and the parts diagram.

The second thing is your rebuilt (restuffed) Aerovox cap is supposed to have 4 leads, not 3. However, it was likely a replacement. Please ensure that when replacing the filter caps, that cap #86 was a 10 uF and 8 uF cap in the same can, but not with a common ground. Replacing with 2 10 uF caps is fine, but please note that the negative leads of the 2 caps in #86 go to 2 different places. One goes to the center tap of the HV secondary. The other one goes to chassis ground. This is important because the HV secondary center tap is not grounded to chassis like it would be on post WWII radios. Chassis ground is essentially
B- / C+ on these sets whereas the HV secondary center tap serves as C-. If you are packaging differently so that one half of cap #86 and cap # 87 are in one can sharing the same negative, connected th the HV secondary center tap and the other cap in #86 is separate and connected between Chassis ground and the HV secondary center tap. Please note the polarity. For this particular cap, the + terminal goes to chassis ground and the - terminal goes to the HV secondary center tap. This is because the center tap is more negative than the chassis ground.

Hope this helps.

RE: Philco 36 660X - radiorich - 11-02-2025

Hello MICHAEL,
Welcome to our little world of Philco it looks like MrFixxr answered your questions and
Mr Fixxr that was a good catch on the filter can .

Sincerely Richard

RE: Philco 36 660X - MICHAEL CHAMBERIS - 11-02-2025

Thank you so much, Corrections are in progress.

RE: Philco 36 660X - Radioroslyn - 11-18-2025

Hi Michael and welcome to the group. 

I see you're up there where you can warm your feet year round. Down by Philly myself. If you still are looking for some chassis pics I have a 660 somewhere and I think it's pretty original. When you get ready to do the rf alignment do check the service notes as there are two trimmers that a mislabeled. I got a 660L good sounding set with good sensitivity and selectivity (for 1936).

462ron - 462ron - 11-18-2025

Radioroslyn me thinks you have Michael’s town of Catawissa confused with nearby Centralia where an underground fire has been warming feet since the early 60s! Icon_lol

Ron

RE: Philco 36 660X - morzh - 11-18-2025

Michael


Welcome.

One not. Not really worrisome but...I see you used a piece of wood or wood-based material as the prop to stiffen the caps inside the can.
In one of them the soldered wire seems to touch that wood or pretty close to it.
Thing is, wood is hygroscopic, so is not the best material to be used as an electrical insulator, unless properly treated (and I am not sure what that treatment would be).

This said, you do not necessarily need a stiffener to stuff the caps. The radios are not subjects to vibration, they stay on the floor or a table.
Personally, I simply stack the caps up and wrap it in a couple of layers of fish paper to insulate from the inside of the aluminum can. This provides the insulation and some decent support (no, you should not shake it violently).

Just a thought.

RE: Philco 36 660X - Radioroslyn - 11-18-2025

My map says he's near by (Centralia).
For those who don't know here's a 
documentary on the subject:  https://www.youtube.com/watch?v=Qj5LjacccJ0
Pretty interesting but tragic.