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Author Topic: Symetrix 528E buzzing.  (Read 1775 times)
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N4WLL
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« on: November 22, 2021, 04:55:40 PM »

Hey all, I am in the process of putting a Gates BC-1G back on the air, converted to 75M.
I purchased a Symetrix 528E to use, but it has a horrible buzzing/hum on the output. I can hear the normal audio fine, but nothing seems to cure the buzzing.
Has anyone on here had a similar issue with one of these and knows what needs to be done to fix it? Or is it non repairable and I need to go out and get another one?

73,
N4WLL
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KQ6F
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« Reply #1 on: November 22, 2021, 05:40:46 PM »

Sounds like one or more of the filter caps in the power supply have gone bad.  You can sometimes spot the bad ones by looking for bulging tops.  Or if you have a scope go in there and look for ripple on the supply busses.
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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 #2 on: November 22, 2021, 09:33:21 PM »

Are you sure it is running balanced output into the transmitter?

Don't use phone jacks or RCA jacks.

If hum persists, try lifting the shield on your XLR connector.

73DG
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Just pacing the Farady cage...
N4WLL
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« Reply #3 on: November 22, 2021, 10:47:28 PM »

Are you sure it is running balanced output into the transmitter?

Don't use phone jacks or RCA jacks.

If hum persists, try lifting the shield on your XLR connector.

73DG


Hmm I didn't think of that. I bought it as "un-tested" so I was just plugging into the phono jack and listening as a quick test. I think I can get an adapter to run it into one of my modern rigs and see if the hum is still there.  By the way, have you gotten a chance to see if you have any of those caps?

73
William
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