[Kenwood] TS-440S issue (solved now)

[Howard Holden]

Thanks to all who replied.

Ed (didn’t see a call or last name) was correct, it was a power supply problem, voltage sagging down to 10.5 under load (at the supply, so it’s not a bad cable), where the digital stuff didn’t want to work very well. A substitute supply cleared things up for now. The Kenwood supply is suspiciously low even under no load at just 12.6V, gonna look at the rectifier bridge and the pass transistors next.

73, Howie WB2AWQ

From: Clif 
Sent: Monday, November 10, 2014 5:40 AM
To: Howard Holden 
Cc: kenwood 
Subject: Re: [Kenwood] TS-440S issue

Check the RX BPF diodes on the RF Unit for leakage. Common problem. Usually D6.


On Sun, Nov 9, 2014 at 7:14 PM, Howard Holden <holden7471 at msn.com> wrote:

  Got a TS-440S which has suddenly acted up on transmit – not the dot problem. This is a later issue radio.

  Seems like I’m getting RF feedback into the rig, regardless of which antenna I use, even a dummy load. Problem is particularly acute on 40M but present on 80 thru 17M as far as I’ve checked. Depending on the antenna, I can get only 20 to about 50W out before there’s a buzz on the signal, and increasing power beyond that makes the display blink on and off rapidly and irregularly.

  I find nothing loose internally, I removed and reseated the connectors on the pot control boards thinking there might be a drive pot issue. I’ve relocated all antenna lead-ins and checked the tightness of all connections. Put the keying lead a number of turns on a toroid (T-240-43, which works great for TVI), got choke baluns on antenna lead-ins.

  Any good ideas out there, anyone with a similar problem?

  Thanks

  Howie WB2AWQ/7
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-- 

Clif Holland KA5IPF
www.avvid.com