{Collins} Re: KWS-1 Grid Drive



Tom, Just some thoughts. Do you have a copy of "The Care and Feeding of Your
KWS-1"? It was a old CCA (full magazine size) quarterly written about the
KWS-1. In it is a table of typical interstage signal levels. You are going
to have to get into the exciter with a pretty good scope or RF microvolt
meter and see what is going on. There are many possibilities.You should
start with basics. Check tube pin voltage per manual table. Then start at
the low signal points in the osc/VIF and move forward looking at the drive.
One of the common possibilities is an interstage coupling cap. They are
silver mica and there is an inherent age related failure mode. One of the
tricks in looking for these bad guys is to look at the following stage
control grid voltge. If the coupling cap is leaky, the grid voltage will be
higher than the design (tube pin table) level. This will also cause the
following tube to run too hot.

Do NOT tweek the alignment until you have the right test equipment,
thoroughly understand the VIF scheme and know what you are doing. A good
scope, VTVM and RF microvolt meter is a must and a spectrum analyzer is
recommended. It is real easy to get a KWS-1 misaligned or get the VIF
unstable and be generating spurs.

On that rig, as with many, shotgunning the problem is probably not going to
get you very far.
I wrote that quarterly many years ago and it is a good primer on how to
align and trouble shoot the KWS-1.
I am in the final stages of moving and getting unpacked so I can not provide
a copy, but there are plenty around. A want put out to the list should do
it. I hope, not too far in the future, to be able to supply them as well as
other tech support. Right now I am packed still and focusing on finishing my
shack/shop.
My phone number:
512 847 7010 Home
512 618 2762 Cell

email: wcarns@xxxxxxxxxxxxx

Good luck and let me know how it goes.

Bill
N7OTQ - CCA # 94-0009
K0CXX Trustee - Mogollon Rim Collins Collectors Club


----- Original Message ----- 
From: "Tom Elmore" <tom@xxxxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Saturday, June 09, 2007 12:03 AM
Subject: {Collins} KWS-1 Grid Drive


>   I am still troubleshooting lack of any grid drive on any band on my
newly
> acquired KWS-1. I believe the former ham (SK) hadn't used it in many
years.
> All the power supply voltages check out per the book. I have changed the
> final tubes and the drivers as well as a host of others with the same
> results. I suspect the drivers aren't putting out what they are supposed
to
> but they sure run very hot. The most I get out into a dummy load is about
40
> watts on the Bird but no grid drive indicated.
>
> Thank You
> Thomas Elmore KA1NVZ
> Anchorage, Alaska
>
> .
> SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
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accepted-
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.
SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
      http://www.collinsradio.org/html/membership.html    -paypal accepted-
.
 NETS: Tues & Thur: 3.805 MHz-2000 Central + Fri: 3.895 MHz-2000 Pacific
  SUNDAYS: 14.263 MHz-2000 UTC  +  AM Net: 29.050 MHz-1200 Central
       1st Wednesday AM Net 3.880 MHz-2000 local (ET, CT, MT, PT)





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