[Kenwood] TS940 power supply problem?

Thu, 1 Aug 2002 00:33:12 -0400

I'm finding the same thing in all of my older gear right now. I have an Icom
736 that had the 'infamous' plastic trimmer problem...while I was in there,
I checked a handful of electrolytics, and found as least half of them
leaking at least somewhat.

Since I got my 940 at the same time, I decided to check that, too. I have no
idea how the filter caps in the PS were working at all, and the smaller caps
in the regulator weren't much better! I changed them, and a few bleeder
resistors...the rig had gotten 'noisier' over time, so slowly that I hadn't
even noticed it! That problem is gone now, too!

Now my twins, on the other hand....those 30-year old caps are still working!

Oscillator!

Bill  WA3RA
----- Original Message -----
From: <[email protected]>
To: <[email protected]>; <[email protected]>; <[email protected]>
Sent: Tuesday, July 30, 2002 5:08 PM
Subject: Re: [Kenwood] TS940 power supply problem?

> In a message dated 7/30/02 12:56:11 PM Eastern Daylight Time,
> [email protected] writes:
>
> > From the postings I've read, it appears that there are a lot of '940s
with
> > this
> >  power supply problem.  Mine had the same thing.  Just one day - poof -
and
> > the
> >  smell of burnt electronics filled the air.  I received a bag of parts
that
> > they
> >  replaced, included was a transistor (I assume it was a pass
transistor).
> >
> >  I wonder why '940s are having this power supply problem now?
> >
> >  Its a great rig, but I wouldn't buy one used again (I purchased mine a
> year
> > ago
> >  from AES).  Seems like there's some flaw in the power supply that's
> rearing
> > its
> >  ugly head now.  Hopefully with this fix, it'll be good many years to
come.
> >
>
>
> Hello all ---------
>
> Its not all that surprising that PS problems in older Kenwoods (and other
> rice boxes) are starting to surface.  Most of my rigs are boatanchors
> (Collins, EF Johnson, Heathkit,etc) and that also includes the Kenwoods
> ------ 520, 830s and accessories.  In general, most of the older supplies
are
> showing their age with electrolytics that are acting more as resistors
than
> capacitors.  Rule of thumb here is to perform some preventive maintenance
and
> replace the aging components before they destroy themselves.  Its not too
> difficult to find fresh, new electrolytics and replacement is
straightforward
> in most cases.  Look for aging bleeder resistors while you have the gear
> apart.  A little preventive maintenance  might save you big $$$, months of
> waiting for its return, and extend the useful life of the rig by years.
>
> Just a comment....... Your individual mileage may vary.
>
> 73 de W4MIL
> Chuck
>
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>
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>
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