Hello, I have a 48-1262 that I just recaped, it did not work when I first got it. I completely recaped all the paper capacitors and the electroylics, with the same value. I had to go to a slightly higher mfd in the electrolic caps, but within 20% of value. I have checked the tubes and they are good. I powered it up and no pops or smoking...good so far. I get sound from the speaker, but I can not pick up any stations. I have tried all diffrent antenna variations including the original hook-up...I only get a squealing noise when I hit where a station should be. There is no loud hum or noise in between stations. I have other radios and they get recption no problem, so I know it is not the radio location. What do I do now? I double checked the caps against the schematic and they are correct, I also have a spare chassis that is non-working and all the connections line-up as should be. The only thing that I changed is there were two caps that had a coil wire trap wraped around them and according to the philco service tip the 37A they can be eliminated with no effect. These were I-F bypass capacitors.
Thanks
David

Did the radio squeal before you recapped it?

This set has a loop antenna, which is an integral part of the RF tuning ckt. Make sure that it is all there and that there is continuity between both ends of the loop. You can do this by measuring the resistance across the section of C400 that the loop is across.

If the loop is OK, check the voltages against those shown on the schematic: http://www.nostalgiaair.org/PagesByModel/614/M0013614.pdf

Could be a problem with the alignment. I'm not sure on that but there are others on the forum that may know for certain. When you get the squealing sound, do you hear any music or voice through the noise?

:Hello, I have a 48-1262 that I just recaped, it did not work when I first got it. I completely recaped all the paper capacitors and the electroylics, with the same value. I had to go to a slightly higher mfd in the electrolic caps, but within 20% of value. I have checked the tubes and they are good. I powered it up and no pops or smoking...good so far. I get sound from the speaker, but I can not pick up any stations. I have tried all diffrent antenna variations including the original hook-up...I only get a squealing noise when I hit where a station should be. There is no loud hum or noise in between stations. I have other radios and they get recption no problem, so I know it is not the radio location. What do I do now? I double checked the caps against the schematic and they are correct, I also have a spare chassis that is non-working and all the connections line-up as should be. The only thing that I changed is there were two caps that had a coil wire trap wraped around them and according to the philco service tip the 37A they can be eliminated with no effect. These were I-F bypass capacitors.
:Thanks
:David

Agree with Brian - could be that the alignment is way off.

Hello, I was wondering if the antenna is the whole problem? I have the original cardboard that it came on, but the wire is gone. I was using a small loop antenna of a newer stereo to test out the radio. I was going to make new coils for the old antenna, but do not know how many loops to make. I do not hear any stations just the squealing noise, when I tried diffrent antenna I got diffrent results, although none were music or words. The radio did not work before I started, it had a blown capacitor so I did not test it.
Thanks
David

:Hello, I was wondering if the antenna is the whole problem? I have the original cardboard that it came on, but the wire is gone. I was using a small loop antenna of a newer stereo to test out the radio. I was going to make new coils for the old antenna, but do not know how many loops to make. I do not hear any stations just the squealing noise, when I tried diffrent antenna I got diffrent results, although none were music or words. The radio did not work before I started, it had a blown capacitor so I did not test it.
:Thanks
:David
Hi David
This is just an outside chance, but if you still have the IF Bypass capacitors put them back in, even though the Philco service bulliten says otherwise, they can make a difference.
Mark

::Hello, I was wondering if the antenna is the whole problem? I have the original cardboard that it came on, but the wire is gone. I was using a small loop antenna of a newer stereo to test out the radio. I was going to make new coils for the old antenna, but do not know how many loops to make. I do not hear any stations just the squealing noise, when I tried diffrent antenna I got diffrent results, although none were music or words. The radio did not work before I started, it had a blown capacitor so I did not test it.
::Thanks
::David
:Hi David
: This is just an outside chance, but if you still have the IF Bypass capacitors put them back in, even though the Philco service bulliten says otherwise, they can make a difference.
:Mark
:With the coil traps on them, these coils act as chokes.
Mark

OK, David, it's class time :>) Take out your schematic and follow along:

In order to tune in a station, you need to adjust the tuner to resonate at the particular freq you want to receive. Many sets have an antenna coil (separate from the antenna) - and the secondary of the antenna coil is in parallel with the tuning cap. You adjust the tuner until the L-C ckt is in resonance at the desired freq.

YOUR SET DOES NOT HAVE AN ANTENNA COIL. The antenna loop does double duty - as both the antenna and the antenna coil. The inductance of the loop, in parallel with the tuning cap, forms the resonant ckt. Without a loop of the proper inductance, your whole front-end RF section becomes untunable.

Many radios used a 365-pF broadcast tuning cap, but I can't find the value of yours on the schematic. If you have a cap tester, you can measure it, fully meshed, with the tuner disconnected. Anyway, the tuner's capacitance determines the req'd inductance of the loop.

If your tuner is indeed 365pF, then you can probably scavange an antenna loop out of most any AA5 junker radio and make it work.

Now, what if your tuner isn't 365pF? You can figure out the req'd inductance of the loop by consulting "Prof. Coyle": http://www.crystalradio.net/professorcoyle/professorcoylespiderweb.shtml

You'll need to put in the tuner capacitance plus 33pF (the value of the shunt cap across the tuner shown on the schematic). For example, for 365 + 33 = 398pF, the req'd inductance to tune 560kHz is 200uH. On Prof. Coyle's site, you can come up with the physical configuration of a 200uH spiderweb coil.

Another approach would be to fashion a coil on a spiderform with, say, 25 turns. If the set gets only stations at the upper end of the BC spectrum, then you need more turns, and vice versa.

But, yes, the first order of business is getting a loop antenna installed - and then find out what additional troubleshooting might be involved.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Looking at the first IF amp and its screen bypass cap of C302 …05 ufd…..and then going over to the second IF you will see the tie in of the second screen grid back to the first, such that they both share that C302. Then if you refer to the second IF you will see that IF transformer is bypassed with C306 ? (Clarity issue) .003 ufd. Now both of them go to that common voltage buss line that originates as a stacked B= source off of ground at R102…..120K down in the power supply. Now looking all up and down that common buss I see NO other GOOD low Z RF bypass path to ground except further through those C304 and C 305 caps.
I can’t guesstimate the amount of potential inductance presented by the coil portion of those inductive overwinds on the capacitors cases by not seeing the wire ga as well as the degree of turns utilized. I also think that they should be placed back into the circuit, but ALSO being SURE that the inductive lead of the series arrangement is the lead that is connected to ground side .Without good bypassing of that IF transformer B+ side as well as the IF screen grids, those two stages could oscillate like a Banshee or swamp out the IF strip and not let anything pass, or heterodyne and produce a burbling birdie on tuning into a station at the front end mixer stage.
If this produces results, then concentrate on a proper matching inductance for the front RF/antenna /loop portion of the receiver..
My thoughts.
73 de Edd
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.

:Hello, I have a 48-1262 that I just recaped, it did not work when I first got it. I completely recaped all the paper capacitors and the electroylics, with the same value. I had to go to a slightly higher mfd in the electrolic caps, but within 20% of value. I have checked the tubes and they are good. I powered it up and no pops or smoking...good so far. I get sound from the speaker, but I can not pick up any stations. I have tried all diffrent antenna variations including the original hook-up...I only get a squealing noise when I hit where a station should be. There is no loud hum or noise in between stations. I have other radios and they get recption no problem, so I know it is not the radio location. What do I do now? I double checked the caps against the schematic and they are correct, I also have a spare chassis that is non-working and all the connections line-up as should be. The only thing that I changed is there were two caps that had a coil wire trap wraped around them and according to the philco service tip the 37A they can be eliminated with no effect. These were I-F bypass capacitors.
:Thanks
:David

Does anyone have the orignal antenna for this radio, or know how many loops the antenna should have. I have been playing around with some loop antennas from other radios and it seems to really impact the the sound.
Thanks
David

:Hello, I have a 48-1262 that I just recaped, it did not work when I first got it. I completely recaped all the paper capacitors and the electroylics, with the same value. I had to go to a slightly higher mfd in the electrolic caps, but within 20% of value. I have checked the tubes and they are good. I powered it up and no pops or smoking...good so far. I get sound from the speaker, but I can not pick up any stations. I have tried all diffrent antenna variations including the original hook-up...I only get a squealing noise when I hit where a station should be. There is no loud hum or noise in between stations. I have other radios and they get recption no problem, so I know it is not the radio location. What do I do now? I double checked the caps against the schematic and they are correct, I also have a spare chassis that is non-working and all the connections line-up as should be. The only thing that I changed is there were two caps that had a coil wire trap wraped around them and according to the philco service tip the 37A they can be eliminated with no effect. These were I-F bypass capacitors.
:Thanks
:David

David: Also check the grid voltage on your oscillator tube to be sure it's within spec. If it's not, check the grid resistor value since it may have drifted much higher. It's possible that you're not getting oscillation.
Steve