92 Volvo 940

Discussion in 'Volvo 940' started by Kim Slyns, Jan 15, 2009.

  1. Kim Slyns

    Kim Slyns Guest

    My speedometer/odometer was intermittent for quite a while but has now
    stopped working altogether. Repair is estimated at A$350 so I would like to
    see if I can fix it myself.
    Any ideas anyone?
    Kim Slyns, Jan 15, 2009
  2. Kim Slyns

    James Sweet Guest

    It's almost always solder joints on the circuit board in the speedometer.
    James Sweet, Jan 15, 2009
  3. James Sweet ha scritto:
    Is also probably that electrolytic condenser leakage make problems in
    printed circuit board.
    Clean PCB, eventually repair interrupted PCB wires and replace
    condenser, preferably with tantalum capacitor.
    this is what I have done in my '91 940 speedometer

    Telespalla Bob, Jan 15, 2009
  4. Kim Slyns

    don b. Guest

    I wish I had better news for you but, I've been dealing with the exact same
    issue for a year. What repair business said they could fix it for 350? Be
    cautious of there claims. There are a couple of things that go bad on the 1992
    940 speedometer boards. Soldier is one but, this comes from the biggest issue. A
    capacitor. It goes bad and leaks on to the board. Once that happens the chances
    of repair drop. Still worth letting them try but get a guarantee! I've sent mine
    back three times. Each time they SWEAR it works on the "bench". However, after
    putting it back in the car it was the same. They have had it for months now
    "trying" to get a replacement from a savage yard and put something together that
    I can use. Good luck!
    don b., Jan 16, 2009
  5. Kim Slyns

    James Sweet Guest

    Should have thought to mention that too, I haven't had the capacitor
    problem on 700s, but I have had it with the analog clocks in 240s.

    It's worth replacing all the electrolytic capacitors in things like
    that, they're cheap and most of them fail eventually. Tantalum is an
    option, under most circumstances they last a very long time and do not
    degrade over time or become temperature sensitive, but they are not
    immune to failure either, and when they do, it tends to be spectacular.
    The usual failure mode for a tantalum capacitor is they short circuit,
    and if there's enough current capacity behind them (car electrical
    system for example), they will usually catch fire.
    James Sweet, Jan 16, 2009
  6. Kim Slyns

    Tony Guest

    Tantalums are high density high performance caps with good electrical
    characteristics. At the end of the day capacitors are hard to make and
    they are many many choices which trade off different characteristics. I
    doubt these need to have any special characteristics so the thing to go
    for is life time (Aluminium electrolitic). It can he hard to find this
    in the cataglogue but you want the highest temperature rating with the
    longest life. eg 125C at 5000hrs (105C at 2000hrs is also not bad but
    much more common). Also go for the large parts variants. I have also
    seen solid polymer Electrolitics recently, but are much more expensive.
    Also of course go for a high quality brand (usually Japanese).

    These circuits are not espeically high density and should be repairable
    even it looks a bit messey with extra wire and glue.
    Tony, Feb 13, 2009
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