I do not have a signal generator at Radio Levels at home ie 455KHZ or 1000KHZ

Is there any way to troubleshoot that portion without one? Any tricks? to find where the signal is not coing through. I have checked the Audio section and it is working fine. Next I will check all the DC Characteristics. Then I will need to troubleshoot the Radio parts. Any tips. I can get to one but it is a bit of a hassle. THX

:I do not have a signal generator at Radio Levels at home ie 455KHZ or 1000KHZ
:
:Is there any way to troubleshoot that portion without one? Any tricks? to find where the signal is not coing through. I have checked the Audio section and it is working fine. Next I will check all the DC Characteristics. Then I will need to troubleshoot the Radio parts. Any tips. I can get to one but it is a bit of a hassle. THX
:

Woops I meant IF not IP.

THX

Most of the time you don't need anything but a simple Volt Ohm Meter. With the schematic follow the B+ line to each tube. Sometimes it's just an open resistor. test the oscillator section for the negative voltage at the grid. You can also test all coils RF & IF with the ohm meter.

Bubba,
Sometimes oscillator radiation from another set nearby can be received and used in such cases. Just remember the osc of the nearby set will be 455kHz higher than tuning indicates, and without any modulation (audio) A good DMM will have a terminal impedance of around 10 meg, similar to a VTVM attached to the AVC bus, but you have to remember the sample/refresh rate of a DMM can sometimes fool you. An old analog VOM will sometimes load the bus, but the analog meter movement gives a better indication of AVC. You could isolate the VOM with a 10 meg resistor, but reading may be too low to register properly.

marv

marv

::I do not have a signal generator at Radio Levels at home ie 455KHZ or 1000KHZ
::
::Is there any way to troubleshoot that portion without one? Any tricks? to find where the signal is not coing through. I have checked the Audio section and it is working fine. Next I will check all the DC Characteristics. Then I will need to troubleshoot the Radio parts. Any tips. I can get to one but it is a bit of a hassle. THX
::
:
:
:Woops I meant IF not IP.
:
:THX
:

I have a small, portable shortwave receiver (with digital freq display). Perfect for picking up the oscillator whistle or IF on another set. A scanner might work too?

As Marv says, any 2nd radio can do this, but the freq precision might not be as precise as my digital receiver. Also, my digital receiver tunes below the standard AM broadcast band.

:Sometimes oscillator radiation from another set nearby can be received and used in such cases. Just remember the osc of the nearby set will be 455kHz higher than tuning indicates, and without any modulation (audio)

P.S. With the "second radio" approach, no real need to check the IF. If the oscillator is running correctly, then just peak up the IF xfmrs using the target radio's audio.

If you lack any sort of test equipment (of any kind), you can check to see if the local oscillator is working by placing another AM radio nearby, as others have suggested.

As for aligning the radio, if the oscillator does not have a series padder capacitor, first adjust the IF transformers so that you have reception (if they were fooled with badly enough to make reception impossible, and also knowing that there are no other faults causing the set not to receive anything). Then adjust the IF transformers so that local and distant stations track correctly at the 600 end of the dial. Adjust the oscillator trimmer (parallel) capacitor and antenna trimmer capacitor for good tracking at the high end of the dial (what is recommended in the service literature, or just the general high end of the dial). Go back and forth in this way until everything lines up perfectly. I have had very good results with this method, prior to owning a signal generator, and after I did own one, found that I had aligned the IF transformers perfectly to their frequency.

Where an oscillator padder is used, it becomes a bit more tricky to align the low end of the dial. If you own a radio that you know is calibrated properly (all stations track very accurately), you can listen to that radio to see if the oscillator tracks across the dial exactly the IF frequency above or below the frequency indicated on the dial of the radio in question. Adjust the oscillator trimmer and padder as necessary. Once this has been established, adjust the IF transformers for good reception on the radio in question. Adjust the IF transformers with the radio tuned to a known station frequency, with the dial indicating exactly that frequency. This method can also be used on radios without an oscillator padder. Simply tune to 1400 or where specified on the high end of the dial of the radio in question, and listen on the calibrated radio for the oscillator of the radio in question either above or below the frequency chosen on the radio in question by exactly the IF frequency.

I believe that Edd or Norm also have good suggestions for adjusting radios that use oscillator padders, without test equipment. Can't remember for sure, though, who wrote a good article on that a long time ago. Radios without padders can be fairly easily aligned without any other equipment at all, including another radio, however.

T.

Can someone post this procedure with using the 2nd radio to test the 455 IF? I want to try it. But I am not sure what I need to do and what I need to tune which radio to? THANX Never did this before but I have several tube radios. So it may well work. Just a simple step list will work.

THANX

Bubba

:If you lack any sort of test equipment (of any kind), you can check to see if the local oscillator is working by placing another AM radio nearby, as others have suggested.
:
:As for aligning the radio, if the oscillator does not have a series padder capacitor, first adjust the IF transformers so that you have reception (if they were fooled with badly enough to make reception impossible, and also knowing that there are no other faults causing the set not to receive anything). Then adjust the IF transformers so that local and distant stations track correctly at the 600 end of the dial. Adjust the oscillator trimmer (parallel) capacitor and antenna trimmer capacitor for good tracking at the high end of the dial (what is recommended in the service literature, or just the general high end of the dial). Go back and forth in this way until everything lines up perfectly. I have had very good results with this method, prior to owning a signal generator, and after I did own one, found that I had aligned the IF transformers perfectly to their frequency.
:
:Where an oscillator padder is used, it becomes a bit more tricky to align the low end of the dial. If you own a radio that you know is calibrated properly (all stations track very accurately), you can listen to that radio to see if the oscillator tracks across the dial exactly the IF frequency above or below the frequency indicated on the dial of the radio in question. Adjust the oscillator trimmer and padder as necessary. Once this has been established, adjust the IF transformers for good reception on the radio in question. Adjust the IF transformers with the radio tuned to a known station frequency, with the dial indicating exactly that frequency. This method can also be used on radios without an oscillator padder. Simply tune to 1400 or where specified on the high end of the dial of the radio in question, and listen on the calibrated radio for the oscillator of the radio in question either above or below the frequency chosen on the radio in question by exactly the IF frequency.
:
:I believe that Edd or Norm also have good suggestions for adjusting radios that use oscillator padders, without test equipment. Can't remember for sure, though, who wrote a good article on that a long time ago. Radios without padders can be fairly easily aligned without any other equipment at all, including another radio, however.
:
:T.
:

Bubba,
Haven't forgotten your plea, and unless someone else responds soon, I'll try to put it into perspective for you.

marv

:Can someone post this procedure with using the 2nd radio to test the 455 IF? I want to try it. But I am not sure what I need to do and what I need to tune which radio to? THANX Never did this before but I have several tube radios. So it may well work. Just a simple step list will work.
:
:THANX
:
:Bubba
:
:
:
:
:
::If you lack any sort of test equipment (of any kind), you can check to see if the local oscillator is working by placing another AM radio nearby, as others have suggested.
::
::As for aligning the radio, if the oscillator does not have a series padder capacitor, first adjust the IF transformers so that you have reception (if they were fooled with badly enough to make reception impossible, and also knowing that there are no other faults causing the set not to receive anything). Then adjust the IF transformers so that local and distant stations track correctly at the 600 end of the dial. Adjust the oscillator trimmer (parallel) capacitor and antenna trimmer capacitor for good tracking at the high end of the dial (what is recommended in the service literature, or just the general high end of the dial). Go back and forth in this way until everything lines up perfectly. I have had very good results with this method, prior to owning a signal generator, and after I did own one, found that I had aligned the IF transformers perfectly to their frequency.
::
::Where an oscillator padder is used, it becomes a bit more tricky to align the low end of the dial. If you own a radio that you know is calibrated properly (all stations track very accurately), you can listen to that radio to see if the oscillator tracks across the dial exactly the IF frequency above or below the frequency indicated on the dial of the radio in question. Adjust the oscillator trimmer and padder as necessary. Once this has been established, adjust the IF transformers for good reception on the radio in question. Adjust the IF transformers with the radio tuned to a known station frequency, with the dial indicating exactly that frequency. This method can also be used on radios without an oscillator padder. Simply tune to 1400 or where specified on the high end of the dial of the radio in question, and listen on the calibrated radio for the oscillator of the radio in question either above or below the frequency chosen on the radio in question by exactly the IF frequency.
::
::I believe that Edd or Norm also have good suggestions for adjusting radios that use oscillator padders, without test equipment. Can't remember for sure, though, who wrote a good article on that a long time ago. Radios without padders can be fairly easily aligned without any other equipment at all, including another radio, however.
::
::T.
::
:
:

Assuming that the oscillator of the radio in question tunes above the incoming RF, what you could do is tune this radio to a known strong local station. For instance, in Milwaukee, 620 WTMJ is a strong one, and is low enough on the dial to be effective.

Now place another radio of known good calibration (stations fall pretty much exactly where they should) near this radio. 620+455=1075. So tune this radio to about 1075KC. Listen for the oscillator of the radio in question. Adjust the oscillator trimmer of the radio in question until you can hear it in your 'test' radio (the second radio that you are using to listen for the first radio).

Once you are sure that the first radio's oscillator is adjusted properly, start adjusting its IF transformers. Start with the trimmer of the coil you rewound. Turn it all the way in, and then turn it out one or two turns. Do the same then with the other trimmers. Listen for audio. If you can't hear anything, try with all of the trimmers three turns out, etc. Once you start to hear something, adjust the trimmers for maximum volume. Then go to the high end of the band and re-adjust the oscillator trimmer so that stations fall where they should at that end (if necessary). Then go back to the low end and move stations around as needed with the IF transformers. Repeat as necessary.

T.

T,
If he tunes to the good radio oscillator (CW) at 1075 mHz, there will be no audio, but will there still be a measurable AVC.

marv

:Assuming that the oscillator of the radio in question tunes above the incoming RF, what you could do is tune this radio to a known strong local station. For instance, in Milwaukee, 620 WTMJ is a strong one, and is low enough on the dial to be effective.
:
:Now place another radio of known good calibration (stations fall pretty much exactly where they should) near this radio. 620+455=1075. So tune this radio to about 1075KC. Listen for the oscillator of the radio in question. Adjust the oscillator trimmer of the radio in question until you can hear it in your 'test' radio (the second radio that you are using to listen for the first radio).
:
:Once you are sure that the first radio's oscillator is adjusted properly, start adjusting its IF transformers. Start with the trimmer of the coil you rewound. Turn it all the way in, and then turn it out one or two turns. Do the same then with the other trimmers. Listen for audio. If you can't hear anything, try with all of the trimmers three turns out, etc. Once you start to hear something, adjust the trimmers for maximum volume. Then go to the high end of the band and re-adjust the oscillator trimmer so that stations fall where they should at that end (if necessary). Then go back to the low end and move stations around as needed with the IF transformers. Repeat as necessary.
:
:T.
:

No audio, but you should hear a squeal as you rock the tuning back and forth.