Alignment Problem

[Les Dickson]

I’ve recapped my Stewart Warner Grenadier R-403 and replaced an incorrect tube. It sounds great but it won’t tune any station lower than 600kHz.

• I’ve followed the alignment steps carefully a few times
• I’ve checked the frequencies on my signal generator
• With the tuning plates fully meshed I get 600
• All stations come in somewhat below what the dial indicates
• (I’ve adjusted the pointer so that it begins on the lowest point on the dial when the gang is fully meshed and it ends on the highest point on the dial with the gang in fully open)
• The alignment instructions note that the bottom cover must be on the chassis before beginning but the radio doesn’t have the bottom cover, it’s the way I got it at auction
• Is it possible that this would be affecting the alignment?

[John Greenland]

‘morning Les

It sounds to me ( no expert here mind you) that you have a local oscillator problem. Using another radio, the local oscillator should be 456 kilohertz above the received signal, (I think most of these are hi-side injection) . So you should be able to pick it up at 1056 on the am dial. Is there a missing or broken trimmer on the portion of the tuning cap for the oscillator, I wonder. preventing it from going lower in frequency. You would need to be down in the 990 kilohertz range.

Good luck with it.

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[Les Dickson]

So, I’ve resolved the problem. Somehow when I was adjusting the cap for the low frequency of the broadcast band my meter was indicating a peak that wasn’t from the signal of my generator. I don’t know if it was some sort of harmonic frequency or something else being picked up by the antenna. Once I figured that out I was able to successfully complete the alignment and the stations are tracking properly.

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