[Kenwood] Kenwood TS-940S

Thu, 4 Apr 2002 09:19:39 +0200

I bought a second-hand 940 with a low SN# a year ago, and one of my early
experiences was that with high mains voltage (>232VAC), there was no power
out. The front panel meter indicated very high DC (peak), and then I found
that the transformer was set to 220VAC. I switched over to 240VAC, and it
helped some, but still the DC was very high (I never measured it with a
DVM).

Since I was new to the rig, I was not alarmed by this, and it worked OK for
some months. Then suddenly, a few days before one of the major contests (of
course), I had a burn in the rig. Smoke was comming from the final amp, and
after some investigation I found that the output transistors were blown
together with an electrolytic cap in the base circuit. Further investigation
showed that also the series regulator transistors were blown together with
many of the power resistors in that unit.

Do I need to say that the rig missed the contest? (I didn't)

After replacing all the defective parts, the rig turned up in good shape. I
then realized that the series regulator probably had been defective since I
bought it.

The moral is: check the DC voltage with the front panel meter, and if it is
showing excessive values, be very careful to use the rig. That can save you
a lot of money!

73 de Svein,

LA3BO

-----Original Message-----
From: Cletus W Whitaker [mailto:[email protected]]
Sent: 3. april 2002 23:53
To: [email protected]
Subject: [Kenwood] Kenwood TS-940S

de  WB2CPN  South Central Pennsylvania

Subject is the TS-940S.

Has anyone had trouble with the regulator board in the power supply?

73
- - -

Your moderator for this list is:
Larry Wilson KE1HZ [email protected]

_______________________________________________
Kenwood mailing list
[email protected]
http://mailman.qth.net/mailman/listinfo/kenwood