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Author Topic: johnson Courier Amp Bias Question  (Read 1697 times)
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w3kbs
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« on: June 13, 2016, 08:10:03 PM »
Hello Everyone.
I am in the process of restoring a Johnson Courier. I just finished the High Voltage cap replacement and noticed also a bias voltage coming from what looks like a winding on the filament transformer.
I want to replace the SR Rectifier with a diode and was just wondering what everyone else is using for the replacement.
I believe also the Bias Voltage may rise a bit after the job and may need a dropping resistor just my thoughts.
Thanks in advance for your help.

Bill w3kbs.
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Pete, WA2CWA
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« Reply #1 on: June 13, 2016, 09:47:12 PM »
I replaced the SR rectifier with a 1N400x (don't remember the last number- probably anything from 1 to 7 would work fine). I think the circuit draws between 30 and 40 ma. Didn't add any additional resistors nor did I change any of the existing component values.
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Pete, WA2CWA - "A Cluttered Desk is a Sign of Genius"
w3kbs
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« Reply #2 on: June 14, 2016, 09:10:07 AM »
Hi Pete.

Thanks for the info. I'll be changing out the capacitor also. Neat little Amp. Plan on using with my little AT-1
Thanks so much for your advice.

Bill
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