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Title: Collins 390 (non A) audio problem Post by: iw5ci on June 15, 2011, 10:16:56 AM I noticed that my 390 receiver has maybe some capacitor issue in the audio board (i suppose).
Unnoticeable while connected to an antenna, when the receiver is disconnected from the ant, i ear some (frrr frr frrrrr i cannot really write the sound :) ) from the speaker not continously but randomly present. If i pickup the audio from the diode output, the problem is not there. So it's probably a condenser leaking in the audio amplifier stage. I have never dismantled a 390 and i need some help of the best and unpainful way to reach the audio amp ad check condensers on it. thank you. Title: Re: Collins 390 (non A) audio problem Post by: w3jn on June 15, 2011, 10:32:13 AM It's easy. Just turn the receiver over, and find the green Philips screws holding the audio/regulator chassis in. Disconnect the wiring harness and it'll come right out. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
This could be a filter capacitor problem, causing the voltage regulators (6082 tubes, a pair) to oscillate. Then again, could be anything. |