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Author Topic: GATES BC-1T  (Read 3339 times)
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KB5MD
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« on: January 25, 2021, 03:41:37 PM »

I have a Gates BC1-T that I use on 75 meters.  Lately it has started to distort the audio along with a decrease in signal strength.   I have rebuilt the audio section and the rf driver section but nothing seems to stop the problem from occuring.  When I first turn it on everything is fine for about 10 minutes and then it will start distorting during a transmission and will continue to do so during any subsequent transmission.
I have replaced all tubes, resistors and capacitors, but nothing seems to solve the problem.  Any ideas, anyone?
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KL7OF
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« Reply #1 on: January 25, 2021, 05:17:06 PM »

disconnect the wire on the electrostatic shield on the mod transformer to verify that the shields are not shorting to the secondary...I had a problem similar to yours and that was the case...I left the shield wire disconnected and the transformer worked ok..gud luk   Steve
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N1BCG
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« Reply #2 on: January 27, 2021, 06:18:56 AM »

It could be worn contractors. I had a BC-1G in broadcast use that would run fine for hours after being off then fail (usually at 4 am). Eventually the contacts get pitted and start to heat from the damaged surfaces.

Unfortunately, there are several contractor assemblies and each one is comprised of tiny parts and springs. On the plus side, you don’t have to work on it at 4 am.
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W7TFO
WTF-OVER in 7 land Dennis
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IN A TRIODE NO ONE CAN HEAR YOUR SCREEN


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« Reply #3 on: January 27, 2021, 10:04:52 AM »

Yep, worn 'contractors' can screw up any job... Wink

73DG
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Just pacing the Farady cage...
N1BCG
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« Reply #4 on: January 27, 2021, 11:22:07 AM »

Yep, worn 'contractors' can screw up any job... Wink

Spellcheckers attempt to protect us from making spelling errors and this happens.
Hey Apple! "Contactor" is a legitimate word!  Sheesh.
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W7TFO
WTF-OVER in 7 land Dennis
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IN A TRIODE NO ONE CAN HEAR YOUR SCREEN


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« Reply #5 on: January 27, 2021, 11:30:49 AM »

You might check the disc cap on the tube mounting bar.

I had that fail gradually, was tough to find.

73DG
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Just pacing the Farady cage...
Opcom
Patrick J. / KD5OEI
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« Reply #6 on: January 27, 2021, 10:01:40 PM »

Yep, worn 'contractors' can screw up any job... Wink

73DG

too-fresh a contractor can also screw up any job...


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Radio Candelstein - Flagship Station of the NRK Radio Network.
KB5MD
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« Reply #7 on: January 27, 2021, 11:58:39 PM »

Finally found it!  My exciter was failing, changed it and now it works fine.  Thanks for the replies.
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