Zapped FT-2980

Discussion in 'Radio Circuits, Repair & Performance' started by KC0WSG, Feb 10, 2020.

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  1. KC0WSG

    KC0WSG Ham Member QRZ Page

    Story is... I brought my gear inside from the van and set my mobile antennae on the table next to my battery. I was adjusting the positive terminal when the screwdriver handle came into contact with the antennae. The radio, not so surprisingly, went dead instantly. Any thoughts on which component likely got fried? I took the cover off and it looks clean inside, nothing obvious. (photo of the board)[​IMG]
     

    Attached Files:

  2. KD0RCB

    KD0RCB Ham Member QRZ Page

    When you say dead, I assume you mean 100% dead--no lights, no sound, no backlite, no nothing. If its not pulling ANY current, something is blown open...and If the 12v surge did come thru the ant. center input, (the center RF center conductor, not ant ground), the small rf amp fets, sm parts, etc, (even if shorted and bad), would not kill the power to the whole radio. I guess I would remove the whole circuit board, and very carefully look for blown foil traces below the board, esp around the ground connections, etc , throughout all the traces. Use a magnifying glass, they can be hard to see. If any are found, repair them. Check the reverse polarity diode at the DC input, but if the surge came thru the antenna input, this diode is probably still good . Also a few B+ voltage checks at main points on the circuit board would be helpful too. (RF Output IC, audio, etc). If missing, trace backwards from there. Good luck, Randy.
     
    KC0WSG likes this.
  3. KA9JLM

    KA9JLM Ham Member QRZ Page

    If you got lucky, Maybe it just blew the surface mount fuse.

    The current went thru the RF out module, So it could be smoked.

    Do you have a schematic ?

    Good Luck.
     
    KC0WSG likes this.
  4. KC0WSG

    KC0WSG Ham Member QRZ Page

    I really appreciate the responses, guys! I was pretty intimidated when I took the cover off and realized I'd need to do solder work at the antennae jack just to remove the board and look beneath it.
    I humm-hawed for a couple of days, then looked at it again and saw that the fuse at the line coming off of the battery blew. I'm embarrassed that I didn't check that first. I replaced the fuse and it works fine now. I'm still a bit confused as to how the spike made it through the entire radio circuitry before blowing out the fuse at the battery... Back in business though:)
     
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    Cool Beans.

    A Fuse is your friend. :)

    Enjoy.
     
  6. KD0RCB

    KD0RCB Ham Member QRZ Page

    Glad you got it figured out! Randy
     

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