[Heathkit] Troubleshooting HW-99

[fritsche]

Hi Raymond, name is Al, W5ADF in Houston.
I have a HW-99 that works OK , except for the
Bargraph indicator. First segment is out with
no replacement available.Alas. But thats another
story.
Perhaps I can help you fix yours, troubleshooting
is really not much different on solid state as it
was in the tube days. You have to divide and conquer
each stage. Iam assuming you have the manual and
schematic and at least a vom. From what you wrote
the power supply voltages are OK. Now the next
step is whats common in both rec and transmit, well
many things but the weakest link is the TR relay which
causes many problems.  In this rig the relay is operated
in receive mode and open on transmitt, the tranmitt lead
from the PA is on the on the common side of contact. So
what gets me curious is that it blows the fuse on transmitt
and there is no receive. Probably not the relay then.

First step might be , why the blown fuse on transmitt.
On the bottom of the rig, on the T/R board, remove
rca plug P103 and put a 47 ohm resistor between
TP101 and Ground. This eliminates the input to the
P.A. board. Key up and see if fuse blows.

I think it will probably blow again.

Second remove P102 from the T/R board which will
eliminate the PA output back to the antennae... If you
now have rec, then in all probability your final Q303
is shorted from collector to emiter, causing the no
receive problem and the blown fuse.

Let me know if I can be of more assistance.
Your Friend Al
W5ADF


----- Original Message -----
From: <W5VPU@aol.com>
To: <heathkit@mailman.qth.net>
Sent: Tuesday, June 04, 2002 9:52 AM
Subject: [Heathkit] Troubleshooting HW-99


> Hello, Everyone.
> I have an HW-99, a 50 watt "novice" cw (80, 40, 21, 10) transceiver which
has
> gone dead on me. I asking for information. I bought this at a flea market
six
> years ago and used it to get back into ham radio after an absence of 18
> years. Worked ok for several years, but then got RST reports of a hum/rasp
on
> transmit. I replaced the power supply filter caps. Used it a short while;
> receiver worked ok, but it blew the house current fuse on transmit and
entire
> radio went dead. I checked the caps I replaced, and they appear to be ok
and
> not shorted. Still shows 12 and 30 volt power at appropriate spots, but no
> receive or transmit.
> I have considered the following actions: (1) Following the manual's small
> troubleshooting guide in sequence; (2) checking each point receiving
voltage
> as shown on the schematic (I am unsure about checking transmitting
voltages
> until I can get receive working). After that I would then have to wonder
if I
> blew the final, or ?????
> I became inactive when we used tubes, and to get myself acquainted with
> current solid-state design and practice, I built a Ten Tec Model 1253
> regenerative receiver about three years ago. I have installed some boards
> into a couple of transceivers I recently bought. I'm not intimidated by
> radios, but most of my building/repair experience was in the 1940s through
> the 1970's on tube radios.
> Anyone have anything happen similar to my experience with the HW-99?
> Anyone suggestions for troubleshooting sequence or details, and repair
(other
> than just selling it for parts)? I'd like to get it going again, for my
own
> sense of accomplishment if for no other reason.
>  Thanks a bunch.
> Raymond, W5VPU
>
>
>
>
>
>
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