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amplifier noise

danny maxwell

Member
Feb 13, 2017
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I have a kenrich eagle 500 amplifier and it still powers up and has output but a loud hum comes on transmit . any suggestions or help would be greatly appreciated. thanks
 

If caps are the issue you might as well replace the rectifier diodes while youre in there. They used small diodes in parallel for the rectifier circuit. If memory serves me there are 14 in there. There is room to drill out the holes and put 3 amp diodes in there. You'll only need half as many diodes that way.

Someone sells recap kits for them on ebay but youre better off hand selecting your own. They send you the bare minimum voltage ratings. Caps have gotten smaller over the years and the replacements in the kit are too small physically to fit properly.

A guy bough a kit for his kenrich and I installed them for him. Since they were not an exact fit some drilling of the board was required. Higher voltage ratings will get you bigger caps that fit better and they will be more reliable.
 
If you are hearing an acoustic hum in the room when you key it, bad rectifier diodes are the usual culprit.

If the hum is heard on the air modulating your carrier, filter capacitors probably, an internal short in a tube, maybe.

Or both?

Seems to me that they used parallel pairs of 1-Amp diodes to increase the current capacity. We replace each parallel pair with a single 1N5408 3-Amp rectifier. They're cheap insurance if you spend money on the filter caps.

73
 
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If you are hearing an acoustic hum in the room when you key it, bad rectifier diodes are the usual culprit.

If the hum is heard on the air modulating your carrier, filter capacitors probably, an internal short in a tube, maybe.

Or both?

Seems to me that they used parallel pairs of 1-Amp diodes to increase the current capacity. We replace each parallel pair with a single 1N5408 3-Amp rectifier. They're cheap insurance if you spend money on the filter caps.

73

I had a hum in one of my amplifiers and it turned out to be the rectifier board.. If its heard over the air, then thats most likely the cause..
 
THANKS TO ALL FOR HELP !!! CHANGED OUT FILTER CAPACITORS AND NOISE IS GONE. THIS WEBSITE IS GREAT FOR INFORMATION AND HELP ALSO SAVING TIME AND MONEY HUNTING FOR THE PROBLEMS. THANKS AGAIN
 

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