SB303 w/scanalyzer question

[Chuck Penson]

Chuck,

Am forwarding you SB-620 questions to the Heath reflector where I am sure
you'll find some good advice.

I think the tap for the 303 would be OK, although it will require you to
re-peak the receiver.  Re the lack of trace, could be lack of HV due to
bad filter caps, or check the value of the resistors in the intensity
control circuit. They have a tendency to drift up in value. Then again it
could be a  bad CRT--3RP7. Although for testing purposes a 3RP1 will do
nicely.  You got me on the 8.9 IN question. . .no clue there. Sorry.

Good luck with that stuff!

Cheers,  Chuck / WA7ZZE

====================================

>Question - I have the Scanalyzer which is wired for 3395 Khz IF. The
>manual provides no  hookup for 303 but does mention that the input to
the scanalyzer
>should be connected to  the output of the mixer JUST PRECEEDING the 1st
IF.  The >303 uses a  FET for the Mixers,  etc.  Question.. given the
output of the FET is HI-Z >(and that is OK  since the output of the tube
is around 10-20K ohms).. will connecting >the scanalyzer input
excessively load  the 303 FET mixer?  Will the mixer put out >enought
signal to drive the scanalyzer?
>
>From my dim recesses of mind, I believe that the loading should be
>minimal (using the 7 pf coupling cap) as in the 301, but I'm n ot sure
if the mixer >output will be too low given it's a solida state mixer
versus the tube mixer in the 301.
>
>Suggestions/comments appreciated.
>
>Also, the previous owner connected a wire to the SOURCE of the 2nd
>mixer and labeled it  8.9 IN.  MY question.. since this is the input to
the 2nd mixer, why
>would someone want  to inject an external 8.9 Mhz into the 2nd mixer
when the >internal signal is still present? Could it be that he was
tapping OFF the 8.9 input to >drive an external device and just labeled
it '8.9 IN' as an identifier to  himself?
>
>curious..
>
>I'm having a ball with the green boxes!  Also, the scanalyzer has a
>'dead' display. No CRT trace. based on the age and reading the skizz,
I'm inclined to
>look at the rectifiers as the first culprit with the connex wires as the
second.
>Thoughts? I have spare CRT's for that and monitorscope too and I've been

>recommending your heathkit book to all those who have em. What a great
reference!
>
>Chuck k3ft
>

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --