[Bigreddog42]

I finished electronic restoration of a 48-1270 this month. This is my second project and could not have completed without the resources at Philco radio.com. I really appreciate y’all. 

I bought this console at a flea market in March. It looked challenging to me in terms of electronics but the cabinet was in good shape and I got it for $ 50. 

I spent a lot of time studying the Philco service manual and testing tubes, and transformers. All of the tubes except the 5U4 were good. The output transformer was bad and I replaced with a Hammond 125D. Speaker looked good and the field coil was good too. I treated it with Thompson’s water seal (spray can). 

I started recap about end of May. I replaced the electrolytics, all the paper caps, and quite a few resistors. I was surprised at having to replace so many resistors but maybe my desoldering work put too much heat to them. Seems like caps were tied to lugs at lowest layer with resistors and wire leads on top - pretty tedious for a nearsighted old man. Maybe a desoldering station would be a good investment. I finished the recap along with a new line cord and fuse around End of June. 

She worked pretty good on first test after replacing rectifier. I had a small problem with some high pitched tones when volume was low and treble high. After finding the VC, bass, and treble pots were pretty much in spec. I remembered the inverse feedback implemented in the output transformer secondary coupled to the VC through a resistor network. The high side of the secondary is supposed to connect to the R203/204 network but since I used the Hammond 125D it was easy to connect the wrong lead. It was an easy fix once I discovered my error. 

The record changer work was pretty much just cleaning, lubrication, and minor adjustments all per service manual. I am amazed at how good radio and record player sound. The scratch eliminator circuit actually works pretty well. 

Cabinet work consisted of thorough cleaning, and sealing of all interior surfaces with shellac. I used Howard’s Restore-A-Finish and followed up with Howard’s Wax. I cleaned the door pulls with a vinegar/water solution (1:9). It’s not perfect but looks really good in my man cave. 

I’ll attach pictures and post anything else pertinent as it comes to mind. I’ve done AM alignment but not FM and will likely have a post on that subject when I have time to work on it. Again, thanks for all the help.

[klondike98]

[Bigreddog42]

Now that it is daytime and I’m more coherent here are some more things that might be useful:

This was my first Philco experience so the first thing that I dealt with was the Bakelite terminal block. I cleaned out the insides and put two new .01 mf Y2 safety caps from each line to ground. I also connected a new 8’ polarized line cord and fuse inline on the “hot” side (also the on/off switch side). The Philco repair bench has a good article on Bakelite blocks: https://www.philcorepairbench.com/how-to...te-blocks/

For capacitors and resistors I sourced from JustRadios.com. I replaced paper capacitors with a mix of polypropylene and polyester film tubular axial capacitors. I used .5 watt carbon comp resistors except for a few cases where 1 watt were spec’d in the service manual. They can be identified by looking at part number ending in “4340.” There are a couple in the power supply section for voltage dropping and a couple of voltage dividers in the scratch eliminator circuit plus maybe a couple more here and there. I did not replace any mica caps.

When evaluating output transformer replacement  I found this article helpful: http://www.radioremembered.org/outimp.htm
I measured the dc resistance of the voice coil at 3.0 ohms. I used the rule of thumb to arrive at impedance of 3.75. I used the Hammond table for their 125D transformer: https://www.hammfg.com/electronics/trans...a-125e.pdf
I settled on lugs 3 and 5 for primary impedance between 7000 and 8800. Lugs 2 and 4 would yield 9000 to 11200. The 6V6 push-pull setup is good for maybe 10000 ohms. I also tried lugs 2 and 4 but really couldn’t tell any audible difference. Would be interested in comments on which way is better.

The power transformer performed per spec once I slowly powered up with variac. It fooled me for a while because the primary wising measured 2.8 to 3 ohms. The schematic indicated primary should be 28 ohms. I guess this is an eeeor on schematic but I have seen this same indication
for other radios incorporating this transformer so it concerned me for a while. Here is an article on power transformers I found useful: https://www.radioremembered.org/xfmr.htm

Other than the 5U4 rectifier the only questionable tube I had was the FM1000. It has a small crack in it but still works. It is not really easy to find but I spotted one on eBay recently and snagged it. Better be nice to your FM1000s.

The M-4 record changer is in good shape. I cleaned, lubed,  and adjusted according to service manual. I had to get a needle for the magnetic cartridge. I found an Astatic N501-3s on eBay. It works fine. You might also find a viable replacement at thevoiceofmusic.com. They also will service idler wheels. I’ll probably have mine serviced before too long but it works pretty good even though the rubber looks a little dry.

The Philco service manual has really good alignment instructions and is available in the Philcoradio.com library.

I’ve got some video of this thing operating and will try to post soon.

[Bigreddog42]

You will likely run into C306 condenser-choke assembly and may wonder what to do. It is a wave trap. There is an article about it here:https://www.philcorepairbench.com/i-f-wave-trap-and-special-capacitor/  I initially left it as is and radio performed fine. I replaced it with a new .01 mfd and noticed no difference. I believe simple replacement with a capacitor of similar value is the generally accepted practice. See photo attached.
   

[Bigreddog42]

Record player doing its thing: https://vimeo.com/manage/videos/578176538

New home:     

[mikethedruid]

I ran into the same question when restoring my 48-482; in that schematic the part is C404. I just stuffed a modern yellow .01MDF condenser inside the tube from the original condenser (one of the few times I have done this, I usually don't bother with trying to make everything look original, but in this case the diameter affects the inductance) and wrapped it five times with 24 gauge wire in series with one end of the condenser. It works fine, and provides the filtering intended by this part.

[Bigreddog42]

That’s a good idea mikethedruid! I still have that thing. I might do same. Did you test or notice any performance difference?

[Bigreddog42]

Here’s a resource that I found helpful and I noticed Ron Ramirez mentioned it lately: https://www.antiqueradios.com/philcorestorer/index.html

One of the recommendations mentioned in this page is the practice of j-hooking the new caps to old cap leads. I can see the advantage of not disturbing lead dressing and overheating other components during desoldering. I’ve only used this approach sparingly in tight places or around “delicate” parts. What is general best practice?Would appreciate your thoughts as I contemplate  another 48-1270 that’s out in my garage.

[Ron Ramirez]

I did?!?

I actually try to avoid j-hooking, doing so only when absolutely necessary.

[Bigreddog42]

I wanted to give attribution for stuff but I do not mean to imply you advocate j-hook technique. Sorry. Here is reference to article with some helpful tips: https://philcoradio.com/phorum/showthread.php?tid=22242

Appreciate all you do!

[Ron Ramirez]

No worries, and thanks.