The PHILCO Phorum
Model 87 with a few issues - Printable Version

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Model 87 with a few issues - duce67us - 06-22-2026

This landed in my lap, but came with issues to overcome.   First, the Field coil seems to be open.  
The second hurdle is the interstage transformer that drives the push/pull output tubes has both an open primary and half of an open secondary.  

Thoughts on best avenue for repair? 

Donor radios seem to be available and had thought about replacing entire contents with parts from a different unit.   

Thanks in advance

RE: Model 87 with a few issues - morzh - 06-22-2026

>>This landed in my lap

Given the weight of these, that should've hurt...


Having dealt with four of this generation radios (86, 96, 111 and 112) I have also encountered these issues.

The field coil is the worse of the two. Very few people rewind these, and myself I do not do that, so I opted for buying a speaker. I found one on eBay end of last year.
I also saw one in Kutztown.
There are more on eBay but the prices are crazy and not really justified, so I waited for a reasonable one to come along.
Both H and G speaker will work, but you might have to work with the plug and see if the transformer mount o the speaker will not interfere with the speaker mounting in your specific radio.


As for the interstage transformer, I think I used 124B. Though probably, should've used 124C (same transformer, half-price due to "B" being higher quality iron, but in 87 or even in my 111, I do not think it matters much. Not sure why I did it.)

Here is the page where I did it.

https://philcoradio.com/phorum/showthread.php?tid=9096&page=5&highlight=philco+111


But if Hammond seems too expensive, the Ratio being 3:1, the Tubesandmore one seems to also fit (same 3:1 ratio)

https://www.amplifiedparts.com/products/transformer-audio-interstage-10-ma

I think the reason I used Hammond was it is rated for 45mA while the Tubesandmore is rated at 10mA primary current, but then I am not sure I know what current it is used at. At the time I thought it was 10mA and so I wanted some cushion.

RE: Model 87 with a few issues - RodB - 06-22-2026

We like nice photos!

I just checked my interstage transformer and it is from a model 650 and seems to have a 2 : 1 ratio. Might work till you can get a replacement.

RE: Model 87 with a few issues - morzh - 06-22-2026

Rod,

If the "authenticity" is one of the goals, it takes opening the old, mounting the new one inside, then soldering it.
And all that given a huge heavy chassis.
I would advocate getting the right one and putting it in.
There is enough time to get one from wherever, considering his Field coil is open. No rush.

RE: Model 87 with a few issues - duce67us - 06-22-2026

Thanks for all the insight. I will definitely check out all the suggestions later tonight.

RE: Model 87 with a few issues - Joe Rossi - 06-22-2026

Very nice cabinet. Joe

RE: Model 87 with a few issues - Arran - 06-22-2026

Open audio interstage transformers is a common failure in early AC sets with push pull audio output stages, such that I'm planning on testing out a solid state substitute I fount in the AWA Old Timer's Bulletin, whilst not authentic it is a more economical way to get a radio working that doesn't really have a high monetary value. The field coil is a little more of a problem since it's part of the power supply in these sets, in some sets it's in the B- return line so it's not as critical as a filter choke. They can be rewound, in whole, or partially, it takes time but it's a bulk wound coil, as long as it's close enough in D.C resistance it will work. There are ways to make a S.S sub for the field coil as well, or to use a iron choke, but since you would still need a replacement speaker anyhow there isn't much to be saved there.
In most sets I have the speaker field coil is usually fine, it's the primary of the audio output transformer that fails, though not as often as an audio interstage transformer, my model 96 had an old Hammond replacement installed and it has failed as well.
Regards
Arran

RE: Model 87 with a few issues - duce67us - 06-23-2026

Again, Thanks for all the info.  I really have no idea of the service history, but I do know that someone was puttering around underneath the hood. Found two electrolytic caps underneath the big can.  When I tested the tubes, One of the 45's tested strong, and the other Weak.  I suppose that something catastrophic happened and it took out both the field coil and driver transformer.