Dear Jim,
I have SPM-19 too but without any manuals. Could you plase check what kind
of input impedance is in "unbal 75" but selected without termination
(infinite). Instrument works great if not gone to couple of error states
caused by impurity in relay contacts (my guess).
73 de Matti/OH2ZT
----- Original Message -----
From: "James Moritz" <[email protected]>
To: <[email protected]>
Sent: Monday, December 02, 2002 8:14 PM
Subject: Re: LF: W-G SPM-19 trouble
Dear Dex,
There are only 2 frequency conversions in the SPM19 - one to the 40MHz
first IF (which is what the 40-65MHz LO signal does), and the second to
the
10kHz final IF. You could include a third conversion to get the demod
audio
out at 2kHz as I recall - but I don't think you could be using the audio
output for level measurement because it has permanently-on AGC. So I guess
the problem you have must lie in the 40MHz to 10kHz conversion oscillator
I have the circuit diagrams for the SPM19, so I will take a look and can
send the relevant diagrams if neccessary. BTW, when you say the frequency
is wrong by 1.792kHz, how are you measuring this? is it high or low? One
of
the manuals also contains a list of error messages, but they usually are
not very helpful - 100 ways to tell you it isn't working!
Cheers, Jim Moritz
73 de M0BMU
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