The PHILCO Phorum
47 1230 no fm - Printable Version

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47 1230 no fm - willydcamaro - 01-31-2018

Hi everyone. Just finished recaping 47 1230, and am works great. My problem is no fm . When switched to fm 1 station is clear and when tuning for other station this one station stays on no matter where I move the tuner. Any ideas ? Thank you.

RE: 47 1230 no fm - klondike98 - 01-31-2018

Welcome to the Phorum!
Icon_wave

If I recall correctly that set has both pushbutton tuning and manual tuning. Pushbutton tuning is a separate tuning circuit that bypasses the variable cap tuner. To tune manually there is a button to switch to the manual tuning circuit.

RE: 47 1230 no fm - Warren - 02-01-2018

Klondike is right , the pushbutton tuner is separate from the manual tuner and needs to be tuned separately by coils on top of it. If you are using the mannual tuning, does it move the pointer?

RE: 47 1230 no fm - willydcamaro - 02-03-2018

Thank you for the replys ! The tuning cap is moving, but fm is completely silent. I tested all tubes except the 7F8, which my tester had no info on. I will have to make some voltage measurements around the 7F8. I cleaned the bandswitch with deoxit,but that changed nothing. Thanks again !

RE: 47 1230 no fm - willydcamaro - 02-07-2018

Well I really need some help. I replaced 7f8 tube with a NOS, still no fm. I then proceeded to make the feedthrough mod on c419, now I have no AM or Fm or SW. Could this mod mess up the oscillator ? I'd appreciate any help or comments.

RE: 47 1230 no fm - klondike98 - 02-07-2018

There is a troubleshooting guide in the service bulletin. Might be the best way to locate the problem.
See: http://www.audiophool.com/Philco.html for the bulletin.

RE: 47 1230 no fm - willydcamaro - 02-07-2018

Thank you Bob for replying. I have that and guess I'll have to start all over. Regards, Bill

RE: 47 1230 no fm - klondike98 - 02-07-2018

I've not worked on that model and don't have the troubleshooting skills to suggest something, maybe others will have some thoughts.

RE: 47 1230 no fm - Ron Ramirez - 02-07-2018

(02-07-2018, 07:10 PM)willydcamaro Wrote:  I then proceeded to make the feedthrough mod on c419, now I have no AM or Fm or SW. Could this mod mess up the oscillator ?

Well, it could...if you did not hook things up correctly when you replaced C419. Also, you could upset the screen grid voltage of the two IF amplifier tubes when the radio is set to FM. I think some voltage checks and circuit tracing is in order.

RE: 47 1230 no fm - willydcamaro - 02-07-2018

Hi Ron. Thank you for replying ! I will start taking voltage checks tomorrow. Thank you Guru !!

RE: 47 1230 no fm - willydcamaro - 02-08-2018

Good Morning. I noticed on the instructions that a metalized film cap should be used for c419. I used a polypropylene.....would this make a difference ? Thank you,Bill

RE: 47 1230 no fm - willydcamaro - 02-09-2018

Hi everyone, Weii I undid the C419 mod, soldered in the old C419 and I now have AM and Shortwave back. Now back to no FM.

RE: 47 1230 no fm - Ron Ramirez - 02-09-2018

You must have connected the new C419 incorrectly...or else your new capacitor was bad (it happens, but fortunately very rarely).

RE: 47 1230 no fm - willydcamaro - 02-11-2018

Well...still at it. Now I have 303 volts from 5y3gt to R100 15 k resistor but nothing after the resistor. Any help would be appreciated, Thank you, Bill

RE: 47 1230 no fm - Radioroslyn - 02-11-2018

Hi Bill
Well seems like you have a few possibilities. 15k resistor is open/ bad connection or something that it  is feeding the 190v is shorted. One way to troubleshoot this short issue would be disconnect parts that go from the 190v circuit to chassis ground like C-102A while using an ohm meter across the 190v line. Set unplugged of course. What you are looking for is a resistance of abt 5000 to 100000 ohms or so. What you have now is something very low probably in the 10's or  100's of ohms. Ecaps will look like a short at first (for a few seconds) as as they are being charged by the voltage from the ohm meter. But after words should show a high resistance if good. Connect the black lead to the chassis from the meter. The other way around it may try to charge the cap backwards showing it to be shorted when it isn't

Happy hunting!