{Collins} KWS-1 Questions



Fellow Listmates,

I could use some expert help.  There’s lots of sharp guys here, so I hope you all can help me.  

I’ve been trying to get my KWS-1 to the 100 percent level for quite some time.   I’ve been battling this issue off and one for a while and would really like to solve it for good.

I have a problem with neutralization on 10 meters.  Sometimes it acts as if it’s neutralized, and other times it is not.   I have a couple of specific questions:

1)  At what serial number did Collins change from 4X150’s to 4CX250’s?  I’m not sure which one really belongs in mine.  Right now, I have 4X150’s in it.  The serial number is 836

2)  Since I am having trouble in the area of the neutralizing the driver stage, I looked closely at the neutralizer trimmers and their associated components.  I’ve already replaced many of the old silver micas with new ones.  What I found puzzled me.  It appears that C-237, a 33 pf padder across C-715 FB neutralizer trimmer, was missing!  It also appeared to me that it was never there.  It did not look as if the lugs on the trimmer had ever been disturbed.  Is it supposed to be there or not?

RE question #2, I added the 33 pf padder and it made things worse.  So, maybe they deleted this part??  So, I removed it.  Any comments on this one are welcome.

I am using the procedure outlined by W8MAQ.  When I perform the procedure, it seems to go as outlined in the paper.  I do note that if I don’t wait for transmitter to warm up thoroughly, the setting for C-283 will change some.  At any rate, after neutralizing the transmitter, it works fine through 15 meters.  10 meters is a different story.  It appears to tune up fine in CW, but when I put it into SSB mode, keying the mic results in full 500 mA plate current.  There have been times that I’ve had it working on 10 meter SSB ok, but eventually, it starts misbehave.  

Most of the capacitors in the driver stage have been replaced.  However, I am a little concerned about C-277 (1.5 pf) and C-281 (5 pf).  I don’t know what type of capacitors these are.  I replaced the 5 pf with a 5 pf silver mica (maybe a problem) and have not replaced the 1.5 pf yet.  I’m not sure what to replace it with.  I’m wondering if these could be the problem??

Sorry for such a rambling and complicated post.  I tried to make it as succinct as I could.  Any ideas or pointers would be appreciated. 

I love my Gold Dust Twins.  I use the A LOT.  As in the previous post where a guy talks about using his S Line to work DX, I work lots of DX with my Gold Dust Twins.  Lately, TX6G  and FT5ZM on CW.  I’d love to get my KWS-1 fixed right so I can just enjoy it more.

Look for me as N0S in the Missouri QSO Party next week!

73
Mike WB0SND


Michael Marx
sndtubes@xxxxxxxxxxxxxxx

www.vacuumtubes.com
SND Tube Sales
105 N. Division St.
Bonne Terre, MO  63628







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