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Originally Posted by johnda
Hi Radioactive,
Thanks, I do have the original manual with it. There is only one electronics repair shop about a half hour away from me. I inquired about them doing the alignment and they just threw up thair hands! It turns on, and I can hear ststions, but it just isn't the same as it used to be. When I was a novice working with a Globe transmitter I used it as my receiver. I don't have the heart to let it go.
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Kids <GRIN>!
Old communications receivers are not all that hard to align; all you need is an RF generator and a lot of time. You start at the back end and align the last IF first then work to the front. When you have the IF's aligned you do the AM, or lowest band if there is no AM, starting with the oscillator. Align to 600cps (hertz didn't even rent cars back in the days we are talking about) by ajusting the coil, then 1600cps with the trimer on the tuning condenser (now called the tuning capacitor; another renaming, why can they not leave things as they were?). Check at 1000cps if the dial is right on you have it made, but most likely it will be off. What do you do if it is off? Glad you asked, you align the ocillator again, and if needed again, and again. Sometimes it takes a half dozen tries to get everything right (usually because someone had screwdrivered it). Once the oscillatator is aligned you align the RF stages working from the oscillator forward. Congradulations the IF's and AM band are now aligned. Now do it again for each band starting with the oscillator, do not touch the IF's they are already aligned. If no one has messed with the receiver it takes about an hour to tweek the alignment on a 6 band receiver, if someone has figure 6 to 8 hours. If I remember correctly the SX-100 was a single conversion receiver, there are additional steps for dual or triple conversion receivers.
If you have an FM band you need more stuff to do it. A sweep marker generator and an oscilloscope helps a bunch. That is because you want the IF's to operate in a bandpass rather than a peak mode and there is no way to do that properly by ear, however you can probably find a shop to do the FM for you as they usually have someone around who knows how to do that; but maybe I am guessing wrong about that these days.
In other words it looks complicated, but it really is just multiples of the same process that you have to do for each band. Have fun.