[Yaesu] Re: FT-1000D - slight lightening damage to (modified) LPF unit - the solution

[A10382]

Lightening strikes, even indirect ones can wreck havoc.  And all of the
damage may not be instantly discovered.

With that much lightening damage, you might consider calling your
homeowner's insurance company.   They typically cover such damage, and
will send someone to check to be sure you have not missed anything.

My daughter and son in-law had a strike at their house about 3 years
ago,  The electrician the ins. co sent found 4 other things that had
been fried (including an air conditioner compressor that would bot have
been fired up again for another 6 months and an unused 3rd door garage
door opener).

The insurance company covered EVERYTHING for them (parts AND labor),
with no deductible.

Check YOUR policy...

If you have the ARRL radio policy, it wall also cover any lightening
damage less the per unit deductible.  ARRL's policy covers actual
replacement value and/or repair costs including parts, labor, and 2way
shipping.

If you can, get a copy of the weather reports from the NWS for your area
(or some newspaper clippings) to verify that there was
thunderstorm/lightening activity in your area at the time.  The NWS
archives their warning reports and radar pictures for some time.

==========
Best of luck,
Frank

 ._._.


----- Original Message -----
From: "Chris Codella, W2PA" <w2pa at arrl.net>
To: "YAESU List" <yaesu at mailman.qth.net>
Sent: Thursday, July 14, 2005 10:29 PM
Subject: [Yaesu] Re: FT-1000D - slight lightening damage to (modified)
LPF unit - the solution


> Just thought I'd follow up on the resolution to this problem in case
> anyone else runs into this.  Thanks to the group for the various
> suggestions and observations.
>
> The lightening strike was not direct and took out a couple of other
> random pieces of electronics in the house, including a circuit board
in
> the second floor air handler for the heat and A/C, the DSL modem and
the
> wireless router.  When I turned on the FT-1000D no signals could be
> heard in the main receiver so I knew something got zapped (the
> sub-receiver was unaffected, as was the transmitter).  But as I was
> tuning across 40m that night, I heard very weak carriers from
> broadcasters so I knew most of the rig was fine and the damage was
> likely very close to the antenna connection and I was hearing strong
> signals bleeding through very slightly.
>
> That tuned out to be true, and all the damage was confined to the LPF
> unit, on which two capacitors, two transistors, and a diode, got
fried.
> All of the components were associated with the receiver/transmitter
> antenna switching circuit.  There are at least two versions of this
> circuit, the original one having an NPN self-biased compound
transistor
> (BA1A4M) controlling the ground side of the relay coil, and the later
> one that uses a PNP version (BN1A4M) controlling the 13V side; in both
> cases it's designated Q7203 in the schematic.  My FT-1000D looks like
it
> has the LPF board for the original circuit but had been modified by
> Yaesu per the service manual to become the later version.
>
> Anyway, that relay driver transistor, Q7203, got zapped along with
> Q7202, an NPN that's half of a complementary pair of transistors that
> biases the main switching diode either to isolate the transmitter when
> on receive or connect it to the output when transmitting.  The pair
also
> drives Q7203 to control the relay that isolates or connects the main
> receiver antenna.  In addition, C7288 got fried, an SMD capacitor in
the
> transmit line that isolates the DC in the switching diode from the
> antenna output.  And C7278 a bypass capacitor on the collector of
Q7202
> (the one that died) met its end as well.
>
> It's difficult to find some of the original parts Yaesu used, but
there
> are readily available substitutions.  Here's a summary of replacement
> parts I used that all work fine.
>
> Q7202 - the 2SD667 can be replaced with an NTE289
> Q7201 - the complementary PNP, a 2SA684, can be replaced with an
NTE290
> (this wasn't necessary in my case)
> Q7203 - these self-biased PNPs seem to be available here and there.
But
> I used a Fairchild GC557B which is the equivalent to the the
stand-alone
> transistor used in the module (a 2SA1175), combined with two small 10k
> resistors, one in the base lead, one base to emitter.
> C7278 - 0.1uF disc that ought to be in most junk boxes, or at Radio
Shack
> C7288 - This one was a bit tricky.  I first replaced it with a 200V,
> 0.1uF SMD capacitor (Kemet C1812 type).  Although it has the same
rating
> and value as the other one in the transmit line, and matched the specs
> in the schematic, it was quite a bit smaller in size than the one I
took
> out.  When I fired up the rig, it self-destructed as I applied full
> power on transmit.  I speculate that it was mismatched with its mate,
> C7287, on the other side of the switching diode and took an over
> voltage.  So I replaced both capacitors with a the 1000V rated Murata
> 2220 (GRM55DR...), which by the way is just about the same size as the
> 200V one I took out, and everybody's happy now.
>
> All the parts were available from Mouser.



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