[Collins] KWM-2A help (long)

[Al Parker]

Hi folks,
	I don't know Collins like I know some other stuff, I need some help.
	I brought a nice KWM-2A home from Shelby 2 wks ago, to replace the one 
that's been flakey (quick change in freq.).  This one came from a fellow 
I've known for 20+- yrs, he'd used it himself, but put it aside abt 2 
yrs ago.  Said he'd replaced the finals & driver then.
	It receives fine, but transmit is a problem.  75 & 40m now are OK, 100+ 
watts out, but very little on 20 & above.
	I have done what I think is usual/normal, before any alignment I 
studied the block diag. & schematic.  I removed the shield cans & 
carefully, with a dropper, cleaned the bandswitch wafers with DeOxit. 
Ckd (& tried other) tubes in the xmt RF string.  Did a lot of 
measuring/observing with the scope.
	Here's where I am now, after several days.  I think the problem is 
in/around the 2nd xmt mixer, V6, & the xmtr RF amp, V7.  The xtal osc. 
sends 30v p-p on 7.2mc and 20v p-p on 14.3mc to the 2nd mixer.  I 
'think' 20v is enough, but??  (it does go less on higher bands).  I've 
tried a different 6U8 xtal osc., I know they're flakey, no dif.  The IF 
input to that mixer doesn't get bandswitched, so it should not be 
varying by band (I think I ckd).
	Here's the problem evidence, input to V7, xmt RF amp.  3v p-p on 3.9mc, 
2v p-p on 7.3 mc, 400mv p-p on 14.3mc.  That's tuned in the mixer's 
plate, T-3 coil & slug varied by "Exciter Tuning" ctrl, and switched 
variables w/parallel fixed capacitors.  All these caps on various bands 
do peak as expected.
	What am I missing?
	Any help or thoughts greatly appreciated.  I'd like to use this unit on 
the Vintage Sideband Net tmw at 2PM ET, 14.292-1/2.
tnx, 73,

Al, W8UT
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