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Title: johnson Courier Amp Bias Question Post by: w3kbs 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. Title: Re: johnson Courier Amp Bias Question Post by: Pete, WA2CWA 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.
Title: Re: johnson Courier Amp Bias Question Post by: w3kbs on June 14, 2016, 09:10:07 AM Hi Pete. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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 |