1. Forum
  2. Usenet
  3. SCI.ELECTRONICS.REPAIR

  • Over-voltage protection

    From Cursitor Doom@21:1/5 to All on Sun Mar 26 18:11:25 2023
    Hi all,

    I have a Yaesu FT857 transceiver which requires a nominal supply of
    13.8VDC. I accidentally fed it with 30VDC and something went 'phut'
    after about 60 seconds and there was a whisp of smoke. Nothing too
    dramatic, but it no longer works. I'd forgotten it has an on-off
    switch which doesn't entirely isolate the supply. The thing was
    switched off at the time this happened so whatever's burned-up must
    have still been connected internally despite that.
    I'm guessing this radio will have some kind of over-voltage protection
    built in, but how is this protection typically implemented? Is there
    anything to particularly look for?

    -CD

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Reinhard Zwirner@21:1/5 to Cursitor Doom on Sun Mar 26 19:33:22 2023
    Cursitor Doom schrieb:
    Hi all,

    I have a Yaesu FT857 transceiver which requires a nominal supply of
    13.8VDC. I accidentally fed it with 30VDC and something went 'phut'
    after about 60 seconds and there was a whisp of smoke. Nothing too
    dramatic, but it no longer works. I'd forgotten it has an on-off
    switch which doesn't entirely isolate the supply. The thing was
    switched off at the time this happened so whatever's burned-up must
    have still been connected internally despite that.
    I'm guessing this radio will have some kind of over-voltage protection
    built in, but how is this protection typically implemented? Is there anything to particularly look for?

    In any case,

    here <https://elektrotanya.com/yaesu_ft-857_sm.pdf/download.html>

    you can download the manual.

    HTH

    Reinhard

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to [email protected] on Mon Mar 27 09:32:33 2023
    On Sun, 26 Mar 2023 19:33:22 +0200, Reinhard Zwirner <[email protected]> wrote:

    Cursitor Doom schrieb:
    Hi all,

    I have a Yaesu FT857 transceiver which requires a nominal supply of
    13.8VDC. I accidentally fed it with 30VDC and something went 'phut'
    after about 60 seconds and there was a whisp of smoke. Nothing too
    dramatic, but it no longer works. I'd forgotten it has an on-off
    switch which doesn't entirely isolate the supply. The thing was
    switched off at the time this happened so whatever's burned-up must
    have still been connected internally despite that.
    I'm guessing this radio will have some kind of over-voltage protection
    built in, but how is this protection typically implemented? Is there
    anything to particularly look for?

    In any case,

    here <https://elektrotanya.com/yaesu_ft-857_sm.pdf/download.html>

    you can download the manual.

    HTH

    Reinhard

    Yeah, thanks for that.
    I had one of those 'iightbulb moments' at 3am: a crowbar! Can't think
    why I'd overlooked that. Just hope the damn thing had a fuse in the
    power lead!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)