Philco 15DX restoration - Printable Version
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RE: Philco 15DX restoration - morzh - 05-16-2012
Well, see if it "jumps" to 1.7M at some point. This may indicate a wear spot in the resistive element.
Your contact is probably OK as you do get 0 Ohms where it should be 0.
RE: Philco 15DX restoration - Bob Andersen - 05-17-2012
You're right - it does seem to jump to 1.7M about 2/3 through the travel. I'll leave it alone for now.
I finished with all the bakelite blocks and replaced a few out of spec resistors and micas along the way.
There is one junction of three resistors and a wire floating in space. That's correct as near as I can tell from the parts placement diagram.
It's right in the middle of the photo at the right end of the brown-black-green resistor. Maybe they just ran out of tie points ?
[Image: http://farm6.staticflickr.com/5325/7219253116_6b1064f1ac_z.jpg]
Now, on to the electrolytics. Here are the two 12 mfd replacement caps i found in the set. The originals would have been 6 mfd.
It would be cool to find a pair of the originals and restuff them
For now, I'll just tack in a couple replacements to get it running.[Image: http://farm8.staticflickr.com/7101/7219252766_222ce16dde_z.jpg]
RE: Philco 15DX restoration - Arran - 05-17-2012
Are there any production dates on those Aerovox electrolytics? Wherever used them was performing a repair on the cheap, most of the Aerovox ones I run across in AC sets at least have an aluminum can not a cardboard tube. Those cardboard ones were junky anyhow, the lifespan was about five years before the electrolyte dried out and they needed replacement.
Regards
Arran
RE: Philco 15DX restoration - Bob Andersen - 05-17-2012
I see 527 and 610. Maybe 27th week of 1935 and 10th week of 1936 ? Both are leaky. No surprise there.
RE: Philco 15DX restoration - Arran - 05-18-2012
Possibly but unlikely that they would not have changed the filter caps since that time if it were kept in service, one would figure that someone would have tried to keep it going through the war years at least. The last Aerovox caps I ran into with a date code had hyphens between the numbers like 10-12-47 or something like that, but then again I'm not sure how long they used that yellow and black label or whether they always dated their caps. Since the set is from 1932 the originals would have been aluminum Philco brand ones, but if you have some older aluminum replacement style ones that will fit in the holes that would make a good substitute for the time being to fill the holes.
Regards
Arran
RE: Philco 15DX restoration - Bob Andersen - 05-18-2012
I think I have a couple 1938 aluminum caps, but none older. Hard to say how long it was in service. The 42 output tubes had been replaced, but most of the others were Philco branded globes.
RE: Philco 15DX restoration - Ron Ramirez - 05-18-2012
Actually, the originals were copper Mershon caps similar to those used in the 70, 90 and later 112.
Mershons were used as late as 1933 as one of the filters in the early production of models 16 and 17.
RE: Philco 15DX restoration - Bob Andersen - 05-18-2012
I thought that might be the case. I've seen them show up now and then for sale. I think someone was (is?) selling reproductions too.
RE: Philco 15DX restoration - Arran - 05-18-2012
I didn't know that Philco was still using Mershon condensers in 1932? I figured that maybe they phased them out late in 1931 since the early Philco 90s had them but the later production ones did not. It wouldn't be to hard to recreate some suitable facimiles out of plumbing parts, some 1-1/8 to 1-1/4 inch copper pipe, an end cap, and a threaded nipple if it's the type of condenser held in with a large nut, a propane torch, flux paste, and 50:50 solder. Some building salvage yards like Habitat have new and used plumbing parts. That being said a pair of aluminum ones would look quite acceptable in there, when I have a set with period type replacements in it I usually leave them alone if they fit mechanically.
Regards
Arran
RE: Philco 15DX restoration - Ron Ramirez - 05-18-2012
Yes, like I said, some early console versions of models 16 and 17 used one Mershon with one aluminum electrolytic.
I think some model 80 sets originally used a Mershon.
The 71, 91, 15 sets...all originally used Mershons. They were held by clamps in 1932 models instead of bolting to the chassis as they did in 1931.
RE: Philco 15DX restoration - Bob Andersen - 05-18-2012
Here's what the clamps look like.
Next, I'm moving onto the big metal box with six caps inside it.
[Image: http://farm8.staticflickr.com/7090/7222745740_1e8990e9d8_z.jpg]
RE: Philco 15DX restoration - TA Forbes - 05-19-2012
There are many ways to rebuild these cans. The below link is to pics I took of one of the cans that I did. What I find helpful is installing a "buss-bar" that is connected to the ground jack of the inside side of the can. When there are many caps to be installed in the can, I bend the bar in a right angle that extends over the rest of the connectors mounted in the can base. This greatly facilitates instalation.
http://s1194.photobucket.com/albums/aa372/TAForbes/Philco%20Filter%20Can%20Rebuild/
RE: Philco 15DX restoration - TA Forbes - 05-19-2012
Oh yes, and with respect to mershons, I have a Philco 43 that came with two mershons.
RE: Philco 15DX restoration - Bob Andersen - 05-20-2012
Thanks for the tips. I was all set to drill out the rivets when I noticed in your photos that it wasn't necessary
[Image: http://farm9.staticflickr.com/8157/7236013580_f5d47ebbd4_z.jpg]
The bottom pulled off quite easily.
[Image: http://farm6.staticflickr.com/5346/7236011786_b5aa9edb34_z.jpg]
I could have done a neater job with axial lead caps, but all I had on hand were radials with short leads. Oh well, they get the job done.
[Image: http://farm8.staticflickr.com/7086/7236014300_839cb29c2a_z.jpg]
RE: Philco 15DX restoration - Arran - 05-21-2012
I've used a lot of those PC board type capacitors with the short leads, a surplus place I used to order from stocked a lot of them at cheap prices. Needless to say I've become very good at adding pigtail leads to those short stubs they typically come with.
Regards
Arran