Kit Horror Stories / WRL Screen Modulator

Brian Carling bcarling at CFL.RR.COM
Fri Oct 11 20:25:16 EDT 2002

GREAT story Glen.

Reminds me a LITTLE of my first kit I built at age 12 or so.

Of course I DID know how to solder properly because dad taught me with his 250
watt (240V AC) iron... Oh, we DID have a smaller one OK, 60 watts or so, shaped
like a pistol! har har! I bet others remember THAT junk iron...

Well, the KIT was a 3 stage TRF receiver for the AM BC band, with EXTENDED
COVERAGE up to about 1.75 MHz that was effected by SLIDING OUT the ferrite
rod on the internal ferrite antenna coil!

You could actually get the old "trawler band" as it was known in the U.K. but not
quite up into 160m Top Band.

The kit didn't work when I assembled it. Not because of bad soldering techniques,
but because I got the BASES and EMITTERS mixed up.

Some guy at dad's place of work who knew elecrtonics really well looked at it and
found the problem quickly, and I soon had a working 4.5V battery transistor radio
with speaker driving volume, and yes all on three transistors!

It was Ingenious!

It was in a grey plastic box with slider switches, shaped kind of like a larger "P-
box" or large soap dish. Maybe the size of a Sony ICF-2010 but nowhere NEAR
as good, he he.

I rode the train one Saturday all the way from Cambridge to Bedford
and back to buy that kit with my friend.

On 11 Oct 2002 at 16:55, Glen Zook wrote:

> I have heard of various horror stories of how kits
> were wired.  But, until today, I had never really seen
> something that qualified as such.
> About a week ago, I was "surfing" through eBay and
> came across what was listed as a WRL microphone
> preamplifier.  Well, a quick look at the photo of the
> item showed that it was not a preamplifier, but the
> relatively scarce WRL SM-90 screen modulator which was
> made for the Globe Chief series of transmitters.
> Since there was less than 15 minutes to go on the
> auction, and since no one had bid on the items (there
> was a pair of high impedance headphones thrown in), I
> bid the minimum.  Well, I "won" the auction.
> The "goods" arrived this afternoon.  A quick look
> inside the modulator didn't show anything wrong.  But,
> then I took a closer look.  The modulator consists of
> a small printed circuit board, an audio transformer,
> an Amphenol microphone jack, an octal plug, and an
> octal socket mounted within a metal project box (the
> two tubes are inserted in holes in the side of the
> box).  Every part had been mounted on the circuit
> board, each lead brought through the opening, turned
> over, cut off to about 3/16 inch long, and a "spot" of
> solder had been put on the end of each wire!  Not a
> single wire was soldered to the circuit board!
> The same thing had been done with the octal plug and
> the octal socket.  A drop of solder had been applied
> to the end of each wire and not a single wire was
> actually soldered in place!  Obviously, whoever built
> this kit over 40 years ago did not have a "clue" as to
> how to build it!  Also, there is no way that the
> modulator could ever have worked.  Thus, the person
> who built it probably put it aside, forgot about it,
> and eventually it showed up as part of his/her estate.
> Now, I have no "beef" with the seller.  He is not an
> amateur, only ended up with the items as part of an
> estate sale, and put them up as what he thought they
> were.  I have been in contact with him not about this
> particular item, but we have been exchanging
> information on other subjects.  He is, in my opinion,
> a real nice guy!
> I had heard some "horror" tales from people who worked
> at Heath about some of the kits that were returned for
> service.  But, until now, I could only consider them
> to be "urban legends"!
> I have already cleaned the board and actually soldered
> all of the components in place, as well as actually
> soldering the plugs and jack.  All that is left is to
> modify my Globe Chief 90A and then I can try to relive
> my first day of upgrading from novice, for my first AM
> contact was made on a Globe Chief 90A using an SM-90
> modulator.
> But, I can now "feel" for those who had to rebuild the
> various kits that were returned as "problems"!
> Glen, K9STH
> =====
> Glen, K9STH
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