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Author Topic: TS-440 DOT repair?  (Read 2375 times)
K5VAH
Member

Posts: 19




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« on: August 27, 2012, 07:47:07 AM »

I have a Kenwood TS-440S/AT that just began to develope the infamous DOT problem. It started out intermittant but is now consistant on all bands. I have read many forums and discussions regarding possible problems and fixes but I am an older person lacking in dexterity and clear vision any more. I would like to know if there is a trusted and reputable person or repair center that can fix my radio. I am located in Texas and any referrals or suggestions would be greatly appreciated.
73's
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W1EL
Member

Posts: 35




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« Reply #1 on: August 27, 2012, 08:20:06 AM »

Check with Clif at www.avvid.com.

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K5VAH
Member

Posts: 19




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« Reply #2 on: August 27, 2012, 08:27:46 AM »

Thanks Eric that is perfect. Much appreciated and 73's
Vic
K5VAH
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K5VAH
Member

Posts: 19




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« Reply #3 on: August 27, 2012, 09:14:10 AM »

Well I decided to open up the radio and see if the ugly brown glue was in the VCO's and much to my surprize it was not and appears to never have had it from the factory. However I did find a VERY SMALL (about the size of a pin head) amount of UBG stuck in between a resistor and Electrletic cap in VCO5 that I removed but it did not solve the problem. I then measured the voltage at the inductor and found it to be marginal and then ever so slightly (1/32 turn) adjusted the transformer in VCO5 and WALLA!!! it is back to good working order again. Now for the burn-in test.
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K5VAH
Member

Posts: 19




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« Reply #4 on: August 27, 2012, 07:51:14 PM »

After I burned in the rig for a couple hours it developed the DOT problem again so then I had to dig further than I really wanted to and eventually found a cold solder connection on the base of Q37 in VCO5. Upon further inspection I also found 3 other cold solder joints on the board so the lesson learned is to look very closely at all of your solder joints for possible cold solder connections that can cause all sorts of problems. Getting parts for these older rigs is becoming more difficult and thankfully I did not have to replace any for this fix.
Case Closed.
Additional Note: Clif at www.avvid.com no longer repairs the DOT problem as he cannot get parts any longer but he does do a lot of other work so check out his page for details.
« Last Edit: August 27, 2012, 07:54:55 PM by K5VAH » Logged
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