[Collins] KWM-2A help (long)-final report

[Al Parker]

Hi Folks,
	Well, it's been 2 wks since I brought this up, and thanks to Jerry and 
others for thoughts.  DW Holtman's CD with great pix and annotations was 
a good help, too.  I couldn't do much on it a week ago, but it's been 
resolved now, the unit is now on the air and doing fine.  I figure it's 
time to let you know what it was.
	I said I didn't know the Collins S-line gear like I know some others, 
and I didn't follow my usual instructions to others, "RTFM".  This 
doesn't explain why it wasn't working to start tho', except the previous 
owner, a friend, said he hadn't used it for abt 2 yrs, and then only on 
75m.
    There are 2 coils that are adjusted by the slug rack, but when you 
go thru the alignment process you don't adj. one of them, L-14, at 
first.  Later you do when you get to 20 mtrs.  It, and one next to it, 
are switched into parallel on 14mc & higher.  All the other coils are 
used on every band.  So, if that one is out, it affects 14mc and all 
higher bands.  When I went thru it, more than once, I missed where it 
said to adj. that one on 14mc.  That's what it needed.
     But, there was another problem that cropped up, I don't know if it 
was bad to start or not, but the carrier wouldn't balance out.  It was 
bad Mon.,  before I started digging around Tues. in that area.  As in 
many rigs, there's a variable cap, and a pot. in the balanced modulator 
ckt to balance the carrier.  The pot was at one end of it's adj., and 
the cap had no affect.  So I figured the cap had gotten stuck together & 
the ceramic top was turning & the silvered disc wasn't.  I pulled it 
out, not easy, and found it was OK.  (I had put a cap ckr on it when in 
ckt & couldn't see any change in capacitance.)  Looked closely & found a 
220 ohm resistor in the balancing ckt had broken, the lead cracked thru 
at the terminal lug it was soldered to.  Put that all back together 
(this was before I found the big problem) and the carrier zero'd out 
beautifully.
     So, I feel a lot better now.  All bands have 100+- watts out, 
great.  It should be on the Vintage SB Net tmw at 2PM ET, 14292.5, hope 
to see some of you there.
thanks & 73,
Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 9/18/2010 7:51 PM, Al Parker wrote:
> Hi folks,
 > 	It receives fine, but transmit is a problem.  75 & 40m now are > OK, 
100+ watts out, but very little on 20 &  above.