[Collins] KWM-2 instabilities

[Bry Carling]

If it was me I think I would send it to an expert repair center.
Best regards - Brian Carling, AF4K





On Aug 19, 2017, at 3:05 PM, Al Parker <anchor at ec.rr.com<mailto:anchor at ec.rr.com>> wrote:

Hi folks,
   I bought a KWM-2 about 9 mo.s ago, have tried to conquer its problems 3 or 4 times since, with no luck.
   I have gone thru neutralizing PA, driver & fdbk.  Have tightened screws, swapped tubes in xmt RF string, DeOxited bandswitch wafers with needle applicator, ckd voltages & resistances on V7 RF amp & V6 mixer, all OK, no change in problem.
   It appears to be working well on 20-80m, but on 15 & 10 it is very unstable.  Plate current won't dip, but will vary with mic gain, plate tuning & exciter tuning.  It goes high, and output is on the correct freq., but when tuning the final plates, it oscillates and freq. changes with tuning.  Sometimes even with mic gain full CCW it remains oscillating, once it's started.
   On 15m, watching the final output on a scope, it varies abruptly in amplitude and freq. when changing exc. tuning.
   My hair gets thinner every time I look at this thing, any constructive thoughts would be greatly appreciated.
   I try to remember that we do this for fun, right?
tnx, 73,

--
Al, W8UT
www.boatanchors.org<http://www.boatanchors.org>
www.hammarlund.info<http://www.hammarlund.info>

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole
______________________________________________________________
Collins mailing list
Home: http://mailman.qth.net/mailman/listinfo/collins
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Collins at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html