Heathkit HA-202A 2M Amp Help

Discussion in 'Radio Circuits, Repair & Performance' started by KE8CPD, Jan 29, 2020.

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  1. KE8CPD

    KE8CPD XML Subscriber QRZ Page

    I am currently working on a HA-202A Amp, when i opened it up i tested the two transistors and found one to be shorted. So I replaced the both of the transistors with the approved (from the schematic, and changed out the one other component needed). I re-aligned the amp and figured i would give it a qso test, about 2 minutes into the qso the output power dropped to about half. I tried to realign the amp again and no luck getting any more power out.

    In a last ditch effort i removed the transistors and tested them, and they are both ok still. So i am currently at a sticking point. Not sure what the next steps should be. I have though of going though the matching circuit and making sure all of the components match the specs called out for it.

    I can get photos and what ever else that would help.
  2. KD0RCB

    KD0RCB Ham Member QRZ Page

    If both output transistors ARE still good, is there 13vdc on ea collector? I'm assuming the relay driver transistor is properly closing the relay on transmit, if not ,check that transistor also. Since the rf drive signal, and transmit signal all travel through the same relay, it may have oxidized contacts inside , due to age, etc. You may try to reburnish its contacts inside with a relay reburinishing tool, to restore proper contacts again. This is a simple amp, and cant be anything too difficult. Good luck, Randy.

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