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TM-742 Power issues

Discussion in 'General Technical Questions and Answers' started by KI5PLA, Jun 18, 2021.

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  1. KI5PLA

    KI5PLA Ham Member QRZ Page

    I just received a Kenwood TM-742 from a friend who informed me last time he used the radio it worked fine. I installed the radio in my Ram 1500 Pickup connected directly to the battery. At first the radio appeared to work fine; however, we I started the vehicle the screen went blank. Pressing the PWR button did not turn the radio back on. I recycled the power and hit the power button and nothing happened. Finally after repeatedly pressing the PWR button many time the unit came back on. I repeated the process again and instead of the screen going blank a dash appeared in the middle of the screen and the back light of the display seem dimly lit. When the screen is normal the radio is operational with no problems. It's just the power issue I'm experiencing.

    Does anyone have any thoughts on the issue?
     
  2. WA0CBW

    WA0CBW Ham Member QRZ Page

    Try powering the radio from a 12 volt power supply and see if it works ok. If it does then look at how it is powered in the vehicle.
    BB
     
  3. KB6HPD

    KB6HPD Premium Subscriber QRZ Page

    Hi there,
    I have both the 741 and 742 and had the exact same issue, along with all the display icons coming on. It was intermittent as well. After looking at the radio internally, I found many of the caps in the head were leaking, on both radios. These radios although the best built by Kenwood (in my opinion) are old and this is a common problem, along with the internal batteries, which also may be a problem. I had both my radios re caped and no issues. I did not do the recaping as I had them sent out to a great service place no longer in business.

    Service manuals etc. are readily available on the internet.

    Good luck!

    Mark
     
    W1PEP likes this.

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