[vecher]

ALL, I seem to have a problem with the alignment on the SW band. The AM band aligned without any problems. But the SW band ,signals are heard on 2 frequencies. What I mean is say a station on 12 MHZ I can also hear on approx 11 Mhz. This happens all across the band signals are approx 1 Mhz apart. also about the same signal strength. Its probably an alignment problem but I followed the instructions I think correctly?

Any clues?? Is the shortwave band that difficult to align?

Thanks
Skip..

[Radioroslyn]

Try turning the output of your generator down and the receiver volume up. Me thinks you are hearing a harmonic from your generator.
Terry

[Nick3092]

I believe it could also be the image signal. It's usually around 900kc lower than the true signal. The exact number depends on the IF frequency.

[vecher]

Ok thanks I am hearing on the air signals. The higher freq is the real signal. Listened on a another receiver.

So probably I aligned it wrong. Maybe I used the wrong peak aligning the Osc. or to much signal from the GEN.. I will realign and try again..

Thanks
Skip..

PS next problem will be the phonograph Oh goody..

[vecher]

ALL, Still having issues with the SW alignment. I restarted the alignment from scratch. Still the same problem of stations coming up on 2 frequencies. About the same strength. This is on the air signals and also when using the SG . I reduced the SG power very low so as not to overload the receiver. But still same Issue.

What am I missing? I looked at schematic and didn't see anything obvious.

Has anyone played with this model?

Skip...

[vecher]

ALL, Still having issues with the SW alignment. I restarted the alignment from scratch. Still the same problem of stations coming up on 2 frequencies. About the same strength. This is on the air signals and also when using the Signal Generator . I reduced the Signal Generator power very low so as not to overload the receiver. But still same Issue.

I did find a Cap that was way out of Tolerance right in series with the SW coil. I replaced it with a new Silver mica cap. Will try alignment again .

Has anyone played with this model?

Skip...

[vecher]

Well, Replacement of the Capacitor did nothing. Still same problem.. So I am out of guesses. Will move onto the phonograph next to see if I can get that part working since no one here I guess has played with this model or is offering any suggestions.

Skip...

[Ron Ramirez]

Folks, can anyone help Vecher out here?

[klondike98]

I can cheer from the sidelines....but don't have a clue as to what to suggest

[Eliot Ness]

Skip,  just to clarify a couple of things.  Did you replace all the wax caps and and any out-of-tolerance resistors?   Are all tube shields in place? 

You mentioned earlier that the AM band aligned properly, does AM still play OK?  What signal generator are you using, and do you have another working radio with SW (or a frequency counter) to verify it is putting out the correct frequencies?

Lastly, can you list, step-by-step, the exact procedure you are using to do the SW alignment?  Sometimes it is a simple thing we are overlooking that causes us problems, so maybe someone will spot something you're missing.

Here is a link to the schematic and alignment info for anyone who wants to help:

http://www.nostalgiaair.org/Resources/494/M0013494.htm


 

[vecher]

Ok, Thanks for the reply..

PS AM plays perfect. Right on Frequency and lots of stations.

I did replace all caps. Minus the Mica ones except one Number 27 a 185 uuf was replaced because it was inline with the SW osc coil. Only resistors I replaced were 3 that was for the 2 7C5 output tubes. One tube was running a lot hotter than the other. Now they both are same temp. and volume increased..

No tube shields present all loctal tubes.

Signal Generator is a HP 8657A Calibrated. Freq counter is a HP 5385A calibrated. I use a output meter TS-585 C/u or a HP 400F AC voltmeter.

PS the inside of this is very crowded. Really hard to get at parts. That being said I will try to check all resistors. Whats a good % out of tolerance. 20 % or less. here is a picture of what the inside looks like..

[Image: http://i292.photobucket.com/albums/mm38/...py7nbl.jpg]

I used the alignment procedure. SW is the last step before FM alignment. its step # 5.

Thanks
Skip..

[Eliot Ness]

Yikes, that is a tight chassis!  As for resistors I'd say over 20 or 30%, but if they're hard to get to and not in the SW area I'd probably leave them be unless they are more than 30%, especially since your AM is working good.

Sounds like you have a good signal generator.  How far apart on the dial do these frequencies duplicate themselves? 

I'd pay particular attention for an open antenna coil or other problem in the SW circuit..... there are a lot of contacts for band switching.... I'd make sure all of those were clean and making good contact.

Good Luck!

[vecher]

John, Ok thanks for the reply. Yes its a mess. Started to check the resistors and all are OK so far. But I did find a Mica (again) that was way out of spec. Should be 375 uuf and It reads 875 uuf. Its in the SW circuit. I will replace that its not to hard to get to.

The freq are approx 1 Mhz apart. I think its the image freq the instructions say the image is .910 KHZ. So what ever is supposed to block the image is not working correctly.Or I am not aligning correctly or on the right peaks.

Thanks for your help..

Skip WB4YVO

[vecher]

Well, After replacing 4 more mica caps. The radio is now working correctly on SW. Not sure which one was causing the problems but at lease now its working. So I want to thank everyone for all the help. Without you guys it would have been much harder.

So now on to the phonograph that the BOL has been taken out of head. Maybe at Kutztown I can find some parts..

Thanks Again everyone..

SKip...

[klondike98]

Good news!