re: HW-9 problems

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From: Duffer (hduff@ica.net)
Date: Wed Dec 27 2000 - 09:16:36 CST


Hi Barry.
The first thing to do is study the schematic and use some reasoning.
i.e., The rig works everywhere else on TX and RX so it can't be anything
too serious.
You said that the HW-9 is not transmitting... Is it receiving on 40m ?

If it is also not receiving on 40m then you want to check around the HFO
of the Oscillator circuit board. (Top of the rig.)
This circuit affects both RX and TX.
Check that the HFO crystal is oscillating (21.830 MHz). You can try
tuning L125.
Also check the tuning of the bandpass filters for the 40m section on
that same board (L103 & L104). The tuning is critically sharp and you
have to have both tuned to the right spot for optimum output of the HFO.

I recently had a similar problem with an HW-9 that I picked up and it
turned out to be a bad crystal.

If it is receiving on 40m but just not transmitting, you want to
concentrate on the 40m TX bandpass filters on the T/R circuit board.
This circuit affects TX only.
Try adjusting L403 and L404. Again, the tuning of these is sharp and you
have to have them both in the right spot for optimum performance.
Failing this, I would suspect a bad contact on the main band select
switch.
Use your ohm meter to chack for proper continuity where direct contact
should be seen when 40m is selected.
Check for continuity through the output BPF and look for possible shorts
to ground.

Hopefully, you have a schematic and can follow my suggestions.
Let me know more details as you start looking into it.

Cheers de Hugh VA3TO

Have a very nice HW9 bought used (how else?) about 2 months ago. Works
fine
(as unmodified HW9s do) in all respects except one - no RF output on 40
metres. All other bands work respectably for an HW9 - and appears to key

and
function normally on 40 BUT no measurable RF out when I key.

Ideas? Has been suggested to me that the output toroid core may have
deteriorated and coil needs to be replaced - but what sources are there
for
correct parts?


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