Collins KWM-380-- repair / advice / tips?.

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William van Coller:
 :) Hi All,

I have become the proud owner of the SECOND Kwm-380 in South Africa-(perhaps the whole of Africa as well..), and am about the start the repair process.
YES, I am aware of the CCA, but am asking the question here--so here goes:
The rig has been stored most of it's life, and when the previous owner tried to switch it on-apparently the tantalum caps that supply the synth. board got fried.
It is a bit of a concern--cap's don't just blow willy nilly, but could have happened due to the long storage.
I HOPE one of the regulator pass devices aren't short..

What other things should I look for-perhaps you have restored one of these yourself?.

73 de William

Gregory J. Beat:

It is a bit of a concern--cap's don't just blow willy nilly, but could have happened due to the long storage.
Tantalum capacitors, of this era, DID have a habit of launching like a rocket from a PC board.
Dangerous, without safety glasses, when this happens on electronics work bench !

I HOPE one of the regulator pass devices aren't short..
That can be a potential cause.  Do you know how to test?

There are a handful of top KWM-380 experts in Cedar Rapids, IA area (Collins HQ, radio was mfg. nearby in Anamosa, IA).
These qualified Collins employees (some in support and design) SHOULD be sought for advice -- this radio is NOT for Novice techs, due to scarcity of some parts and  low number of these radios and military HF-380 produced.
Jim Maccani, WØHUP is a very good Collins tech on the KWM-380.

Jim Maccani - WØHUP
4140 Elkhorn Drive N.E.
Cedar Rapids, IA 52411
Phone: +1-319-393-0094

Hal Guretzky - K6DPZ
Land-Air Communications
95-15 108 Street
Richmond Hill, NY 11419
Phone: +1-718-847-3090
FAX: +1-718-849-8279

Greg Anders:
Oh yeah, I second the opinion/observation that tantalum caps are known for "uncaused" explosion.
I have a Tektronix scope in which a tantalum in the power supply went "boom" luckily while in operation with the covers on.... Tantalum capacitors are bombs when they fail, and they are so
tiny for their explosive power....

Gregory J. Beat:
William -

As I remember, only 2,000 of these radios were produced from 1979-1983.
I lived in that area, when the production lines were ending in 1983.

There were ~ 20 factory modifications for the KWM-380/HF-380 during this period.

WARNING - The October 1979 Owners Manual - INCLUDING the PDF that is floating around on the web has a MAJOR MISPRINT.  The REAR Power connector wiring shown in 1979 manual is wrong and WILL cause damage to your transceiver.
The correct owners manual is the SECOND EDITION - dated January 1, 1981
and a scanned PDF is available (January 1 , 1981 - Owners Manual), here:'s%20manual%202nd%20edition%201%20January%201981%20(sm).pdf

Bob Grinnell at Surplus Sales of Nebraska (USA) acquired many of the remaining/spares parts,
when the KWM-380/HF-380 production lines were shut down in late 1980s.

W2XC personal notes on the KWM-380

In May 1980, Rockwell/Collins produced a training document (PDF, 225 pages):
You will require the KWM-380 Owner's and Service Manuals to go along with this training course.

Self Study Training Course on the Collins KWM-380 Transceiver

William van Coller:
 ;)How about that-two respondents with the same name-!.
Thanks Gregory and Greg for your postings-lots of useful data there and I am sure if I get stuck , I could get help in a flash!.
I am very exited to get the old Gal back on the air-luckily I am very technical , and LOGIC circuitry was my major at college, so it is all a matter of finding the root cause and replacing components that might fail in future-like tantalums in the power supply decoupling circuitry.

Much like the TS-850s with its' capacitor fail issues.

Will send feedback when I get her working.. :)

73 de William


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