SB-102, the saga

[Stewart Lyon]

Ray -- you don't you have that thing fixed yet??  You have more patience
than I do.  It would have been a parts rig for me by now.

I didn't quite follow the below but I wonder if the crystals are off in
frequency or have been put in the wrong place. As you know, the TUNE/CW
crystal is 1 KHZ below the USB crystal.  If they were reversed, it would
put the tune signal way down on the slope of the filter (instead of the
center) and result in a low output (and really low output with a CW
filter switched in). It would also make the USB signals sound strange. If
you aligned the VFO on USB then the shifter on LSB, it would really screw
things up if the USB and CW xtals were switched. Look at Pict. 1-7.

The manual references I make are for the -101 manual. I assume the -102
manual is the same.

If you tune to a quiet place on a band with a lot of QRN, you should be
able to switch between USB and LSB with essentially no change in the
"hiss" frequency. If It does change, it means the crystals aren't in the
right place on the lower and upper slopes of the filter. I have found on
a -301/-401 combination, that both the LSB & USB crystals were LOW in
frequency. This takes some fancy juggling of the caps around the crystals
to get it right.  If you can get a frequency counter or have a reasonably
way to measure the frequency of the crystals, it sure makes it a lot
easier. I used my Kenwood TS440 which was close enuff.

Another thing to check is the wiring of the T/R relay.  Look at Pict..
3-1, check the wire color code of the wires at BE (t/r relay) pins 1,5,9.
 On the 301/401, I spent days finding a miswire here.

Good thing this is a hobby and not a business.  We would all be broke.

Wish we had some of your rain.
Are you on the Eastern Shores, where it rains every time I've been
there??

73, Stu W6CUX.
Winnetka, CA


On Sun, 21 Mar 1999 21:57:07 -0500 "Ray A. Allen, Sr." <w2kbr at toad.net>
writes:
>Hi Gary, Tom, Greenkeepers
>        Hmmmmm another SB102 with output problems.  Shud be
>interesting.
snip
>        But, alas, output still hovers at 50 watts...another strange
>thing I noticed this PM while just killing time listening to the
>activity on 20 meters, there is a very noticable difference between
>USB and LSB....on a dummy load, with white noise in the spkr,
>switching
>from USB to LSB is almost like sw to the CW filter..not quite, but
>almost.....so I went to the antenna again and went down to 80 and
>40 meters, tuning LSB is quite a bit different than tuning USB....
>Seems LSB is rather narrow, and requires a bit more effort to get
>"right-on" freq..while USB signals are rather easy to tune "into"..
>Wonder if LSB xtal is /has gone *funny*......I do recall "tuning"
>the LSB LMO during alignment and did not notice anything strange...
>
>Plate current is still up there, and lotsa grid current....
>just not much in the after-burner.....aw well, what the heck, it's
>raining here anyway, might as well work on this..
>
>es 73 Ray
>

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