Yaesu Quadra Not Working Properly

Discussion in 'Amateur Radio Amplifiers' started by WD9IDV, Aug 14, 2021.

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  1. WD9IDV

    WD9IDV Ham Member QRZ Page

    After 20 or so years my Quadra has started to have an issue.

    Sometimes, when turned on, nothing works properly. The only thing that works are the buttons when pressed, beep. I can not change antennas or operate any other buttons.

    The display is normal with no error codes.

    I can get everything to work properly if I manually manipulate the variable capacitors in the antenna tuner circuit. Doing this gets everything to work properly.
    However, after a few times of turning everything on and off, the Quadra reverts back to a non working state, with only beeps when buttons are pressed. Once again, no error codes, and the display looks normal.

    I'm pretty sure it is the motors and photo interrupters. It seems like the motor or motors get "stuck" and do not allow for a proper boot sequence.

    Any help would be appreciated.

    Robert WD9IDV
  2. KI5X

    KI5X Premium Subscriber QRZ Page

    Unfortunately, it must be the week for this. I offer no help, but my Quadra has stopped tuning as well this morning - it won't even tune into a dummy load. Mine boots, just throws an error when pressing the tune button. Time to find a repair facility.
    Last edited: Aug 14, 2021
  3. W9GB

    W9GB Ham Member QRZ Page

    You can ASK Bill, N4ATS if he would repair your Yaesu Quadra.

    The Quadra VP-1000 HF Amplifier is Particular, in the Order of Power Application.

    Yaesu VP-1000 Manual (2.5 kW Switch-Mode Power Supply)
    The Yaesu VP-1000 AC Power Supply delivers 48V DC at 50A, when operated on 220V mains.
    Technical Supplement

    How to replace R2A, R2B and R2C -- 5.6 Ohm 5 W ceramic resistors
    by Albert Garcia, N8NN
    Yaesu part number J31379004 -- located on power supply board 1.
    These resistors act as a fuse to protect from surges when turning on the power supply.

    The Yaesu VL-1000 Quadra HF/6m Amplifier
    by Adam Farson, AB4OJ
  4. NR1R

    NR1R Ham Member QRZ Page

    the amplifier requires a good cleaning on the inside. dust accumulates around the antenna tuner photo eye.
  5. WD9IDV

    WD9IDV Ham Member QRZ Page

    Always keep my electronic equipment clean and dust free. Photo interpretors were cleaned and motor alignment performed. Thanks.
  6. WD9IDV

    WD9IDV Ham Member QRZ Page

    Problem turned out to be a bad antenna tuner control board. See pictures.
    After twenty years or so of operating, that's okay.
    I replaced antenna tuner control board (CS1552001 VL-1000 TUNER UNIT)
    and realigned tuner circuit.

    All is good now. I'm sure I could have repaired board, but new replacement
    was what I wanted. Okay....Another twenty years of solid performance?

    Attached Files:

  7. KI5X

    KI5X Premium Subscriber QRZ Page

    Did you acquire the part from Yaesu - and can you share the cost please? This is my next step to get my ATU operational again...
  8. W9GB

    W9GB Ham Member QRZ Page

    Photo of the Foil Side (bad board) shows damage (black area), likely due to nearby lightning strike,
    Appears it was near the Relay and capacitor on the board.

  9. WD9IDV

    WD9IDV Ham Member QRZ Page

    Gary, I sent you an email.
  10. WE4E

    WE4E Premium Subscriber QRZ Page

    Glad you're fixed.

    As you experienced, the Quadra doesn't fully complete start-up until it indexes the stepper motors on the air variables in the tuner. It can be as simple as fuzz in the photo interrupters. I had a situation where one of the air variables became sticky and wouldn't turn. In your case, the controller board went tango uniform.

    Some discussion in this thread including some pictures in the last post of what the capacitor assemblies look like out of the unit.

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