Re: {Collins} KWM380 SPARES



Good Call John and you are correct. I was the RF Power Design Manager and
then the Product Manager just before that all happened, but I just went down
the street to another plant and a better position. I kept in touch with the
guys in the group and with my Collins customer friends and you have called
it correctly.

Get a MRF421 C Matched pair and you are good to go. I believe you can still
get them from RF Parts. Motorola also made the drivers


Bill Carns, N7OTQ
K0CXX, Trustee MRCCC
President Collins Collectors Association
Editor, Signal Magazine
Founding Member # AC94-0009
512 618 2762 (Cell + VM)
512 847 7010 (Home + Fax)



-----Original Message-----
From: John King [mailto:k5pgw@xxxxxxxxx] 
Sent: Friday, June 03, 2011 4:51 PM
To: Ken Koval
Cc: Collins@xxxxxxxxxxxxx
Subject: Re: {Collins} KWM380 SPARES

In the  late 1980s and early 1990s I owned a pair of KWM 380s and learned
that the final transistors in the KWM 380  was a house number for a
transistor manufactured by Motorola. It was a super secret at that time. I
began digging for the secret being kept by Rockwell about the manufacture
and the Motorola number for the final transistors in the KWM 380 and
FINALLY, I learned from a Collins employee what it was. He did not tell me
that the final transistors in the KWM 380 positively and absolutely such and
such a number the SAME transistor, but he told me quietly, tongue in cheek,
"that if I replaced them with  Motorola MRF 421 C transistors, I would not
have a problem,"  THAT information is the best according to my 73 year old
memory!!

I did not have a problem, just as he said. I sold the transceivers because
Rockwell discontinued support, service and parts for the KWM 380. In
addition, my son, N5ASM, an engineer, was flying all over the world and had
little time to maintain the KWM 380s. In addition, I felt since they were
orphans that I had better unload them while the price was still good. That
was a miscall on my part but you know what they say about hindsight. I sold
one to a Japanese ham who worked for AIWA electronics in Japan and another
to a ham who lived in some Arizona valley who was famous for collecting KWM
380s and working on them.

I kinda wish I still had one to sit beside my KWM2, 30S1, 75A1, 75A2 and
75A4. 
Of course I am still looking for a deal on a 75A#3 and maybe a 32V1,2,or 3
transmitter.

I hope I haven't given out any inaccurate information. 73, John, K5PGW



----- Original Message ----
From: Ken Koval <kakoval@xxxxxxx>
To: collins@xxxxxxxxxxxxx
Sent: Fri, June 3, 2011 3:49:41 PM
Subject: Re: {Collins} KWM380 SPARES

Dick -

I just replaced Q204 last month on my KWM-380 with a NTE 473 from Mouser at
$7.75.  The PT5701 is no longer produced and the NTE 473 is supposed to be a
suitable replacement.  Physically it is identical.  So far, no problems
electrically.

Ken,  K9PGC

On 6/3/2011 3:35 PM, Dick Gibson wrote:
> My KWM380 has no tx,I have traced fault to Q204 , can anyone help me 
>with as to where I can obtain a  PT5701 or suggest a suitable 
>alternative -  Many thanks  Dick GI3OQR  
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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)

LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx This ONLY goes to the
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_______________________________________________
SHARE THE FUN: JOIN THE COLLINS COLLECTORS ASSOCIATION TODAY !
http://www.collinsradio.org/membership/

 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)

LIST HELP?  ADMIN EMAIL:  collins-owner@xxxxxxxxxxxxx This ONLY goes to the
list admins and does not post to the group!


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