Heathkit SA-2500

Discussion in '"Boat Anchor" & Classic Equipment' started by W5JAI, May 24, 2019.

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  1. W5JAI

    W5JAI Ham Member QRZ Page

    I just acquired an SA-2500 Antenna tuner. It was represented as non working, for parts or repair. They showed a picture of the connections that were not connected.

    When I opened it up I found that the inductor motor was disconnected as stated. I measured the motor winding and it seems normal at about 35 ohms so its not burned out or shorted. Everything seems to work....except the inductor up/down switch. The inductor is NOT jambed and appears to move easily. I have NOT re connected the inductor motor and wont until I have some idea why it was disconnected. All the lights on the front pannel light as they should when the switches are operated. I have not yet connected it to a transmitter.

    Question 1: Could someone have disconnected the inductor tuning in order to use it as a single band tuner?

    Question 2 : Any suggestions for further trouble shooting before I reconnect the motor and a transmitter and see if it works?
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Well sure, someone could have disconnected the motor for a host of unknown reasons but it's pure speculation.
    I'd disconnect the drive coupling between the motor and the inductor and verify proper motor operation without any load on it perhaps using a lab supply to really eliminate variables. If the motor works ok by itself then I'd manually test the inductor drive by turning the motor coupling to see if the inductor moves as it should without too much trouble. If all that works I'd put the whole thing back together and wouldn't worry too much about why a previous owner might have disconnected the motor. But during your testing you might discover some problem that explains why the previous owner disconnected the motor.
  3. W5JAI

    W5JAI Ham Member QRZ Page

    Well I can see that if someone was using it on only one band, and the tuner IS known for its slow speed, that maybe they would just preset the inductor and remove the drive to it forcing the auto tuner to just use the faster capacitors to find the tune. I was just wondering if this might have been a common practice.
    Last edited: May 24, 2019

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