Yaesu VX 5 battery problem.

Discussion in 'Radio Circuits, Repair & Performance' started by W8EJO, Jan 8, 2020.

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  1. W8EJO

    W8EJO Ham Member QRZ Page

    I recently bought a used Yaesu vx-5. The battery was dead and it would not take a charge using the factory charger. I bought a new battery. All seemed well. Then the new battery went dead and will not take a charge.
    Can someone point me to the problem and solution?


  2. WB2LBV

    WB2LBV Ham Member QRZ Page

    Is it the factory plug-in or drop-in charger?
    If plug-in, does the radio indicate charging when it's plugged in? If drop-in, does the red charging light come on?
  3. W8EJO

    W8EJO Ham Member QRZ Page

    Its a plug-in(tested good) and it does NOT indicate charging when it's plugged.
  4. WB2LBV

    WB2LBV Ham Member QRZ Page

    If you know for sure the charger is ok there might be a problem with the DC jack on the radio. Does it power the radio if you turn it on? It should, at least for rx although it won't have enough current for tx.
  5. WB2LBV

    WB2LBV Ham Member QRZ Page

    Also if you have or can make a DC cable to plug into a 12V supply try that and see if it powers/charges the radio.
  6. KF5LJW

    KF5LJW Ham Member QRZ Page

    OK if you know the Charger is putting out a good voltage, and a new battery, then there can only be 1 thing wrong. You have an open circuit between the Jack and Battery inside the radio. Bet you a $1 to a doughnut, the Reverse Polarity Diode between the Jack and Battery opened. Time to break out a DMM and find your open circuit. Might even be the Jack itself as already mentioned.
  7. WB2LBV

    WB2LBV Ham Member QRZ Page

    I don't have my VX-5 any more but I still have the manual, if I get a chance I can look at the power circuit.
  8. G4COE

    G4COE Ham Member QRZ Page

    Ever thought it could be be the charger?

    It may well be putting the right voltage out..... but what about the ripple content due to a blown cap.? So better to measure the on-load voltage and the ripple content on a oscilloscope.... or at least try another charger, even a borrowed one.

  9. W8EJO

    W8EJO Ham Member QRZ Page

    Thanks to all.

    I think I found the problem. The non yaesu charger I received with the radio is only rated at 5v output. The correct yaesu charger (NC-72) is 12v out.

    I'll get the right charger & that should fix my problem.
  10. WB2LBV

    WB2LBV Ham Member QRZ Page

    Yikes, I hope that was an honest mistake on the part of the seller. If you have their contact info let them know and perhaps they can provide the correct one.
    Chances are your original battery is just fine.

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