rca: Ch= RC-459-C; 46X3

Hi everyone. I am new at the alignment application of tube radio's. I have RCA 46X3 that is just giving me fits trying to align it. It has been capped and cleaned and the tubes checked on my tester. But I can't seem to induce the signal for adjusting the if cans/osc. I tried inducing the signal via a .01 cap into the 4 pin of the 12SK7 and adjusting the #2 IF can but I can not hear the signal at all. I also tried to induce the signal by laying the alligator clip on the loop ant. Still nothing. I know these IF cans are way out of whack by now. So I need some help please.

Any suggestions please. I am new at this so I am sure I am doing something wrong.

Thanks !

David  (davidharrisdch@aol.com)

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I use about 15 turns on 6" plastic square holder connected to the Generator and set that near loop aerial or ferrite rod. Then tune to blank spot on bottom of MW (BC) i.e. about 550m or 530kHz

If the set has only an external aerial then I wind about 2 turns of 6' wire near socket leaving the other end open. You need a tone (between 350Hz and 1kHz, 400Hz is fine) and 20% to 50% modulation (30% is good) or you can only see AVC/AGC voltage change. Put audio volume to maxiumum and reduce signal generator level to have "normal" volume level of tone on the speaker.

Generally unless some has already bedn fiddling the IF never needs re-aligned. The L.O. and RF more frequently does as the higher frequencies mean component drift and tube changes have more effect. Also  usually a lot of tempting brass screws that get twiddled when the radio stops. One set had 5 preset capacitors tightened up hard on the mica washers. Owner likely thought "Ah those screws have come loose, that's why it doesn't work!"

The IFT cores on valve (tube) sets are also in pairs, either top and bottom or both accessible at sides on two electrically  separate coils. Both need adjusted, slightly, alternately and there are two "peak" positions, one of which is the wrong core location. You need to change only a little and check ALL the cores a little before changing more. If need be you can put a scope or signal meter on a stage if you have no tone on the speaker due to the two stages tuned differently.

Also the cores are "dust iron" and very fragile. If it doesn't move I soak for a while in WD40 and use a little heat on core from soldering iron. The core and former are easily damaged.

See the second post here

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Hi David.

I am curious as to how you are progressing with this set.  Just a couple of questions:
What make and model of signal generator are you using?
Is there any noise from the radio?  In other words, is the audio stage working?
I'll be happy to help you in any way I can.

Best Regards,

Howard

P.S. Thank you for your service to our Country.

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