[Boatanchors] Boatanchors Digest, Vol 114, Issue 6

[Bill Cromwell]

On 07/04/2013 05:57 PM, bonddaleena at aol.com wrote:
> Hi guys. I did subscribe to the Swan Group on Yahoo yesterday.... Of course, the first looong posting I tried bounced... Ah, well.
>
> Here's what I think is the root of my problem, please bear with me:
>
> I have 2 nice Swan 250Cs (I know, I know). Both receive excellent, and exactly the same, when using my HP 606A SG. One has NO xmit output. I have discovered this is a common problem with these radios.
>
> Not being an x-spurt on xtal filters, I measured the in-circuit resistance of the xtal filters.
> The 'good' radio measures 300K ohms. The 'bad' radio measures 36M ohms. I got to this point by 'scoping the signal. Very little carrier balance seen on the scope. The manual is very cryptic on xmitter alignment.
>
> Since the local Radio Shack is out of Swan IF Filters...... I just can't understand why both receivers are exactly the same, but no xmit. The block diagram shows a signal path through the IF Filter???? Yeah, I can swap them, but I need to understand the problem......
>
> Strange, indeed........
>
> thank you,
>
> ron
> N4UE
>

Hi Ron,

What happened when you did the following...?

Put the dead TX on a dummy load (just in case). Tune another receiver 
and the dead TX to the same frequency. Key up the dead TX. Tune around 
with the good RX if you have to. Do you hear the dead TX with the Good 
RX sitting right next to it? If not...look at V2 - the TX mixer.

You did try that didn't you? If you can hear the dead TX in the receiver 
then look at the rest of your transmitter chain. I didn't look at the 
comic boo....er.... manul very much but I saw a reference to grid block 
keying. Make sure that is working right too.

I'm taking my XYL in for an all day treatment at distant medical center. 
If I can, I'll print the manual and study it more closely while I'm 
otherwise just sitting around doing nothing.

73,

Bill KU8H