[ccomer1955]

    Thanks for adding me to the group. I've learned from numerous threads here, and wonder if anyone can tell me if I'm seeing what I think I'm seeing on this chassis. The power transformer has 12 terminal lugs and they are arranged (with the chassis's controls pointed to the ceiling) 1-4, 5-8, and 9-12 corresponding to the labeling on the schematic. On this chassis, the last four lugs have no wires attached so the leads that provide power to the rectifier are not connected to the power supply. Instead, a Philco part 32-7180n listed on Playthings of the Past as a power transformer is bolted to the chassis between the choke (a 3422) and the first by-pass condenser. In addition, some past technician placed a pair of 8uf electrolytics on the lugs for the filter capacitors. I should also mention that lugs 9-12 on the power transformer show open on my DMM. I can not find a part 32-7180n on the schematic, so I'm guessing the guy who tied electrolytics across the lugs of shorted capacitors tried to power the "D" and "E" lines separately? The thing is, except for all the electrician's tape on the leads coming out of the 32-7180n, the mounting looks original.
The schematic is at http://www.philcoradio.com/tech/images/77.jpg

Thanks for the wisdom in advance.

[ccomer1955]

Spending more time with this chassis, I have a related question. At what point do you decide to use a chassis for parts instead of repairing? This one has a bad power transformer, bad volume pot, bad fourth RF coil, bad input transformer, and not one single working part for the Model H speaker: open VC, open field coil, open output transformer, shattered spider and disintegrated cone. I COULD source the transformers and pot and find a speaker (Gary at Playthings has them all listed), but the cost would be high. The lowboy cabinet is in pristine condition, though. I want to find the guy who repaired this set in the 40s and punch him.

[morzh]

It depends, everyone has one's own threshold of where the joy of restoration becomes pain.
I have recently restored 111 which has more tubes but the same physical type chassis.

I had bad field coil on the H speaker, bad volume pot and bad interstage transormer.
All RF coils were good.

It is all doable, but depends on your schedule. Also it seems that H speakers do suffer a lot, and the type of the pot they used (wheel contact) do too, as well as interstage transformers.
So getting another chassis, unless a known working one, is still taking a chance.

[ccomer1955]

I guess I'll put it in the "long-term project" category and keep an eye out for parts or a better chassis while I move on to other things for a bit. I figure if I buy everything I need from Playthings right now, I'd be spending close to $90. If I luck on to a speaker assembly, I might change my mind about it. Does anyone know whack speaker/feild coil/output transformer combinations work well with this set other than the H model?

In the meantime, I will clean up the cabinet and keep it in my workroom to remind me. I could rewind the RF coil while I have time I suppose.

[morzh]

Model H is the one to use and they regularly pop up on eBay. I bought one just in case and it came handy.


Electrically a speaker from 90 or 20, with pushpull transformer, will work, but the size is different (smaller). And it is more expensive.

[ccomer1955]

Thanks. I'll keep an eye out for the speaker, deal with chassis rust, rewind the coil, and maybe from time to time see about the other parts as financing permits.

[Ron Ramirez]

You will want a speaker that has the small 4-pin plug. Type H was used in models 77 and 96. Type H-2, which is electrically identical, was used in models 111, 112 (early version w/2-45 outputs), and 90 consoles (early version with 2-45 outputs).

An H-2 from a 112 or early 90 would be ideal, as these have open spiders shaped like a 45 rpm adapter and produce the best sound. Type H and early H-2 as used in model 111 have the same solid spider as used in model 20 speakers, which somewhat muffles the sound and decreases fidelity.

[ccomer1955]

Ron, was the small 4-pin plug about the size of a 4-pin tube socket? That is what is on this chassis and what is on the dead H model that came with the set. That opens the search up a bit at least. I can look for 77s, 96s, 90s, 20s, 111s, and 112s, then.

Maybe I should finance the restoration by selling the one globe 45 that came with the set. It measured in the 70s on my Triplett 2314, but it would be hard to let it go.

[Ron Ramirez]

Yes...but it has three large pins and one small pin.

Remember, the 20 speaker is a type K and is only 8 inches in diameter. You need an H or H-2 which is 10-1/2 inches in diameter. The H or H-2 should be significantly cheaper than a K.

[ccomer1955]

Great information, Ron, but I discovered a simply stupid mistake on my part since we talked last. I was working on a recent Ebay purchase (a Heathkit VTVM) when I discovered I had been using a bad alligator clip to measure the output transformer and the field coil. Everything I measured was open because the alligator clip was broken off at the connecting wire. Now, I'm getting 3400 on the field coil (I don't know what the output transformer should measure, but it shows some substantial resistance.
The speaker is still without a cone, voice coil, and spider, but that puts me in a different place. I wonder how hard it would be to rebuild the voice coil and re-cone this speaker? The voice coil is intact, but has a couple of inches of winding that has come lose. I've never done it before, but it might be fun to try. Do you know anything about re-coning? Can I buy a modern cone and trim it to fit, I wonder? Think I'll start reading up on the subject. Looks like the restoration is back on the front burner.
One last question: when I take a more careful measurement of my output transformer, I should be looking for a specific ration between the primary and secondary? The 2848 part is not on the Philco Repair bench, but the one that is there for a push-pull 45 has a 100:1 ratio. Do I look for something like that?

[morzh]

A blond woman comes to a doctor.

- Doctor, I am probably dying. Wherever I touch my body there is that horrible, horrible pain.
- Everywhere!
- yes!!! (she touches herself at the head) Ouch! (she touches a knee) Ouch!! (She touches her belly) Ouch, ouch!

The doc looks at her, then at her hand....

- Maam, I think you have a broken finger.

[ccomer1955]

Yeah, I felt pretty blonde.

[Arran]

What about the power transformer, was that mistakenly condemned due to the broken Ohm meter lead as well?
Regards
Arran

[morzh]

When I read that first I was about to suggest using needle probes as it did look as a bad case of oxidated lugs that needed to be scratched.
Well, not that different.

For the future, even with good probes old soldering often develops oxide film that makes things look like opens, whereas it needs to be scratched/punctured to establish connection.

[ccomer1955]

Power transformer has a bad secondary (lines 9-12) everything that supplies the 80. I was using the needle probes when I looked at that. It's sad. I got excited getting good ohmage on the windings at lugs 1-8. That is why that repair person in the 40s or 50s added the second transformer. I can't imagine how much power the set used with two power transformers. The 32-7180N was only connected to the rectifier and to the mains and the pilot light (wrong in the first place). All the other windings test good, though. I put the set back in the chassis yesterday, but I will take it back out and start over this evening. The soldering that guy did is a mess as well. Big, gloppy misshapen masses with untinned leads everywhere he worked. The good news is that he only worked at the power supply end. No changes past the capacitor block at all, but time has not been kind to the wiring above the chassis, so I will need to do some careful tracing around the pilot light/tuning cap/volume pot areas.
I'm going to give re-coning the H a stab. I emailed John's Vintage and he wants $100 to do the job and the guy in Ohio will do it for $50. Worst case, I can buy a replacement for less and still have some backup parts around. Has anyone ever dealt with these guys before? https://taweber.powweb.com/parts.htm