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Trying to Restore 48-472 code 122 - Printable Version

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Trying to Restore 48-472 code 122 - apERNA1985 - 08-19-2018

I started this small project as a gift for my girlfriend. I found a 48-472 code 122 on eBay and ordered it her birthday is Labor Day weekend so I want to try to get the set working by then. I haven't received it yet but the seller has it up as for restoration or parts the body of the radio looks like it's in great shape. I'm hoping just a recap will bring it back to life. Is there anything super tricky about this radio, and does anyone have a diagram for the code 122? From what I understand there is a code 121 and a 122 and I don't know if the diagrams on finding online are correct for mine.

RE: Trying to Restore 48-472 code 122 - Radioroslyn - 08-20-2018

The Philco service bulletin doesn't distinguish between the 121 and 122 as a matter of fact it doesn't mention a code number. In Rider's it's listed in vol 18 pg 80 under Philco as a code 122.

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-20-2018

Ok, I see the tube numbers are different between the two, is it possible that the caps and resistors are the same? If Philo didn't put out a schematic is there a SAMS number I can look up?

RE: Trying to Restore 48-472 code 122 - KCMike - 08-20-2018

https://imgur.com/omfknIF
Here is a schematic that might work for you.

RE: Trying to Restore 48-472 code 122 - KCMike - 08-20-2018

I had to convert this from a djvu file to PDF, and see its not very clear.
If you have a djvu reader on your computer you can go here and find the schematic and it should be very clear to read. Good luck with your radio.
http://www.audiophool.com/Philco.html

RE: Trying to Restore 48-472 code 122 - Radioroslyn - 08-20-2018

https://www.americanradiohistory.com/Rider-Manual.htm
Goto 1948 and click on PQR then goto page 80 in the Philco section.
Sam's is listed as 43-15 and 48-18. Don't have either one but find it odd
that two are listed. I suspect one is a typo.

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-21-2018

I just got the radio in the mail today, I brought it up very slowly on my Variac, once it warmed up all it did was hum loudly no matter what I did with the volume knob. Am I right thinking I should start by replacing the power supply caps first and see what happens?

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-22-2018

I want to go to a local place today and buy a few capacitors, I sort of understand that the capacitors filter the account to run the radio. Is there any point where it is converted to DC? Would I need any DC caps for this radio or should they all be rated for AC?

RE: Trying to Restore 48-472 code 122 - Nathan Slingerland - 08-22-2018

Hi apERNA1985 -

Here's a clearer version of the schematic (converted from DJVU). KCMike - not sure why the one you converted (from the same source) came out low res.
https://drive.google.com/open?id=1yOHmOCdXrkMmv0qFA3dHtEU5HlNmwwC5

The 117Z3 tube in your set is labeled as the rectifier - it's converting AC to DC. Electrolytic caps are typically rated for volts DC. Have a look at the schematic and replace with at least the voltage listed for the original part ratings. The voltage rating should be marked on filter cap (it's a combination can) - each section may have a different voltage rating. If you want to be on the safe side just replace with electrolytic capacitors rated at 450VDC (or higher). Capacitors of sufficient voltage rating may not be available locally - you may need to mail order them from someplace like radiodaze.com or justradios.com.

By the way - I'd suggest checking out Ray Bintliff's excellent introductory books on radio repair.

"Practical Radio Repair"
http://www.antiqueradio4.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=AM&Product_Code=PRP&Category_Code=Comm

"Practical Radio Repair - Volume II"
http://www.antiqueradio4.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=AM&Product_Code=PRPII&Category_Code=Comm

Tons of great information in both volumes.

RE: Trying to Restore 48-472 code 122 - mikethedruid - 08-22-2018

Here is another book you will find very useful for learning all about radio and electronics. It is downloadable from the site linked in PDF and other formats. https://archive.org/details/Audels_Radiomans_Guide_Edwin_P._Anderson_1945 Good luck with your restoration, and welcome to the forum.

RE: Trying to Restore 48-472 code 122 - 35Z5 - 08-22-2018

The original electrolytics were no doubt 150v, a modern 160v is fine. Can step up to 250 if you like but 450v is major overkill.

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-23-2018

Last night I took the chassis out and then noticed how much Mouse Poop was in the cabinet and I made a big mistake. I took the cabinet and put it in the bathtub and started washing it I forgot to take the dial glass out and as I washed the cabinet I ran water across the dial glass and now a lot of the numbers are almost see through!

RE: Trying to Restore 48-472 code 122 - Ron Ramirez - 08-23-2018

For the dial - Please put an ad in the Wanted Ads section (or check with Radio Daze). Ads are not allowed in this section.

Edit: I looked and Radio Daze unfortunately does not carry that dial.

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-23-2018

Thank you I did post there. Because it was part of my restoration I thought it would be OK to reach out to the guys who were following it also. Sorry about that.

RE: Trying to Restore 48-472 code 122 - apERNA1985 - 08-24-2018

Good news!! I replaced the multi-section filter cap with 3 Electrolytics, and the radio started playing.... No I have a couple new questions.

1.) when I turned the radio on previously in a few seconds I had a very loud hum, now when I turn it on its nice and silent, but I hear some hum when the AM radio is on. Where should I start with that?

2.) The FM does not work at all, when I turn the knob for FM the radio goes silent I can turn the volume and tone up all the way and its dead silent. The tubes seem to stay lit, but its dead silence...

3.) I only twisted the electrolytics together with the wires just to test it. Nothing is soldered in yet. The capacitors the guy at the store gave me were (2) 42 UF and 100UF the original one was 40, 70, and 40. He told me when he replaces filter caps on his old radios thats what he uses. Can the 100UF be the problem?

4.) How does the loop antenna get connected someone cut most of the wires off, but the loop still looks intact.