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Philco 15DX restoration - Printable Version

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RE: Philco 15DX restoration - Phlogiston - 06-22-2014

Yes.





(had to add extra words - message too short)

RE: Philco 15DX restoration - Bob Andersen - 06-22-2014

Quote:This transformer works well unde 10mA and I am not sure why Philco used this mammoth of a transformer (which did not help it) for the interstage while any 10mA half the size would do.

This is the audio output transformer, not interstage.

What little rust there was I've already removed. I suppose I could coat them with something, but the additional thickness will prevent me from getting them all back in.

RE: Philco 15DX restoration - morzh - 06-23-2014

Don't worry about it too much. It will work anyway.

RE: Philco 15DX restoration - Arran - 06-24-2014

The lamination's probably did have some sort of coating on them originally, but then again it is pretty old, it looks like they may have used gun bluing on the metal instead, which is a form of oxide. Transformer cores work better when the laminations have some sort of coating on them, it prevents the core from becoming saturated as quickly. I think that if you could probably leave a sheet or two out when you reassemble the transformer and it wouldn't hurt anything. Trying to rewind a coil or transformer is one of those things that intimidates me, other then one of those Philco RF coil primaries, too much wire and too many variables.
Regards
Arran

RE: Philco 15DX restoration - Bob Andersen - 06-24-2014

Yes, there is some sort of oxide type coating on them. Odd thing is that it seems to add no resistance when I tried measuring them with an ohmmeter. I get about 0 ohm on ones with intact coating vs ones where it's come off.

Here it is all back together. I had no trouble fitting all the pieces back in. I smeared some T9 on the plates which I figure will inhibit rust and add a little insulation. Still waiting for some fresh paint on the frame to dry before I try it out.
[Image: https://farm4.staticflickr.com/3855/14315380367_e6a884423c_c.jpg]
I'm also finally getting around to restuffing the copper caps. I'm using three 2.2uF film caps in parallel to get around the original value of 6 uF. The end is sealed with black hot glue so they're easy to reopen if ever necessary.
[Image: https://farm3.staticflickr.com/2911/14499224632_46894df316_c.jpg]

RE: Philco 15DX restoration - bfrohwein - 06-25-2014

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RE: Philco 15DX restoration - Bob Andersen - 06-27-2014

Here's the rebuilt output transformer ready for testing. I'll save that for tomorrow after I get some sleep Icon_smile
[Image: https://farm6.staticflickr.com/5472/14516350012_1b79515619_c.jpg]

RE: Philco 15DX restoration - Bob Andersen - 06-27-2014

I wired in the copper caps and rebuilt transformer.
[Image: https://farm6.staticflickr.com/5590/14521387024_5ffd37e14f_c.jpg]

At first all I got was a loud hum then noticed one of the 42s was out. A little socket cleaning took care of that and it's playing fine. So I'll keep using this transformer and hang on to the Hammond for a spare or maybe use it in another radio.
[Image: https://farm3.staticflickr.com/2900/14519433351_0fc38cd1d0_c.jpg]

RE: Philco 15DX restoration - Bob Andersen - 06-27-2014

After playing at modest volume for about an hour the output transformer is just slightly warm. Is that normal ?

RE: Philco 15DX restoration - morzh - 06-27-2014

Yes, transformer should be a little warm. As long as it is not hot to the touch.

RE: Philco 15DX restoration - Bob Andersen - 07-08-2014

Here's a project update.

I unmounted the larger speaker's cone, removed the rust and bolted on the refurbished output transformer. I sprayed the frame with a little clear enamel to keep the rust at bay.
[Image: https://farm4.staticflickr.com/3849/14350768870_3ddf46f1d2_z.jpg] [Image: https://farm6.staticflickr.com/5274/14373587249_37d80c6212_z.jpg]

I was about to remount the cone when I noticed the surround material on the original 15DX speaker cone was different. It's a flexible woven material rather than crimped paper. So I decided to use it instead.
[Image: https://farm4.staticflickr.com/3891/14559359812_b9ded27cab_z.jpg] [Image: https://farm3.staticflickr.com/2935/14580293733_3693208774_z.jpg]

As for the smaller speaker, it's the opposite situation. The original 15DX cone is just glued to the frame while the replacement has a metal band holding it down.
[Image: https://farm4.staticflickr.com/3914/14559360282_c8aed2c839_z.jpg] [Image: https://farm4.staticflickr.com/3874/14373766177_5e32983a52_z.jpg]

Now that I've got that sorted out, it's time to mount them in the cabinet. When I ordered a piece of 18"x24" grille cloth a few years ago, I neglected to specify the pattern orientation. Of course, it's running the wrong way so I just sloppily installed it figuring I;d order another piece later. Unfortunately, the supply dried up before I got around to placing an order so I'm stuck with it.

Much to my surprise, my work was so sloppy the cloth easy came off the board and cane be reused. Next time I'll be sure to prepare and stretch and glue with more care.

[Image: https://farm6.staticflickr.com/5553/14562635035_8f8a53b17e_z.jpg] [Image: https://farm3.staticflickr.com/2929/14561798402_4640a0b0bc_z.jpg]

Finally back in the cabinet!
[Image: https://farm6.staticflickr.com/5473/14568962446_af2f0f385e_z.jpg] [Image: https://farm3.staticflickr.com/2937/14592986235_63434e7d62_z.jpg]

RE: Philco 15DX restoration - Bob Andersen - 07-08-2014

I installed a cloth power cord and buttoned up the chassis.
[Image: https://farm6.staticflickr.com/5494/14387814888_7cb9462858_z.jpg] [Image: https://farm6.staticflickr.com/5566/14572695444_9dc305e138_z.jpg]

Here it is powered up in the cabinet with the room lights dimmed.
[Image: https://farm6.staticflickr.com/5540/14592312812_40d3c806e7_z.jpg]

I wonder if there was originally some sort of reflector behind the light ? This bare piece of wood doesn't seem to do much.
[Image: https://farm6.staticflickr.com/5506/14598329602_f75e66d283_z.jpg] [Image: https://farm4.staticflickr.com/3876/14575937166_fdb5dfb31e_z.jpg]

With the chassis in the cabinet, I can now see that the rubber mounts I used on the tuning capacitor are a bit too short so I have some more on the way from Renovated Radios. That just as well because I needed a bunch of other stuff too.
[Image: https://farm3.staticflickr.com/2897/14584292696_d97d5baeab_z.jpg]

RE: Philco 15DX restoration - OldRestorer - 07-09-2014

Looks beautiful!

You need to post a speaker re-coning topic.

Where to get the replacement parts and a step by step instructions on how to do it.

I have a few that need new cones and after paying $75.00 for a 6" speaker re-cone for a $100.00 radio I would love to learn and i'm sure others would too.

Kirk

RE: Philco 15DX restoration - gregb - 07-09-2014

Re-coning isn't that hard, the hard parts is getting the right parts. Kenny Richmond re-coned a speaker on a radio I bought from him and it had a really nice cone with the nice cloth surround instead of the foam one that causes fitment problems. Last time I spoke to him about it he was trying to get a line on a good supply of them so he could offer them for sale.
If you want to try the foam surround cone they are available on the web and they are dirt cheap.

Gregb

RE: Philco 15DX restoration - Bob Andersen - 07-09-2014

I'm OK at repairing cones, but I'm no expert on reconing My only attempt at using a new cone with form surround didn't work that well Icon_thumbdown Partly because the original spider I reused was damaged and partly because the foam surround didn't fit well. Next time I try, I think I'll roll my own cone from scratch.