HW-7 ?s...

[John Clifford]

Greetings,

How many people have HW-7s out there?  How many have performed/installed the
De Maw receiver upgrade?  How many people can actually receive a signal on
their HW-7 if the sending transmitter isn't located on the same workbench?
Does installing the De Maw DC replacement front end hurt or help the value
of an HW-7?

I ask these questions because receiving any signal on my particular HW-7
(purchased on eBay, rcvr DOA) seems to be extremely difficult.  The signal
must be very strong to be received.  I've replaced the detector and
realigned the receiver, and actually heard SOME digital signals on 20m, but
unless I key up another rig on my workbench it's hard to receive any CW.  It
does, however, pick up the 'thump' caused by tapping on the VFO knob.
(Really!  And sends it to the headphones!  This must be what is meant by the
word 'microphonics' as applied to the HW-7's receiver.)  Fortunately (or
unfortunately if it means I still have rcvr circuit problems) I haven't run
into any of the AM broadcast reception problems mentioned with this
particular radio.

I know the HW-7 doesn't have the best reputation as a receiver (to put it
mildly), but surely a bone-stock unit can pick up CW without requiring S9+40
signal strength... can't it?

Some additional ?s...

* After replacing Q1 (the original RCA 40673, new NTE222), my voltages are
much closer to spec BUT... they are still off a little bit.  For instance,
the schematic shows the following as proper voltages for Q1: G1/0 (ok),
G2/3.3v (5.0v), D/12.0v (11.2v), S/0.22v (0.7v).  I'm wondering if my
increased voltages are symptomatic of bad resisters and/or capacitors.  I
checked 'C' on Q4 and it is putting out 13.1v.  I would appreciate it if a
kind soul out there with a working HW-7 would check out the voltages
obtained on Q1 for comparison's sake.

As always, if anyone has some idea(s) on what to check, etc., please feel
free to post with one caveat: this poster is equivalent to a smart monkey (I
can follow directions blindly with the best of 'em) when it comes to
electronics so esoteric explanations that assume the reader knows what he's
doing only leads to increased feelings of inadequacy.

Yours in Heathdom...

 - jgc

John Clifford KD7KGX
Weapons Safety, Inc.
13215 SE 30th St.
Bellevue WA  98005

  vox: 425-649-8623
  fax: 425-644-5302
email: johnclif at weaponssafety.com
 http: www.weaponssafety.com

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