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92 Volvo 940
- Thread starter Kim Slyns
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James Sweet
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Kim said: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?
It's almost always solder joints on the circuit board in the speedometer.
Telespalla Bob
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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
bye.
It's almost always solder joints on the circuit board in the speedometer.
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
bye.
It's almost always solder joints on the circuit board in the speedometer.
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!
James Sweet
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don said: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!
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.
Tony (archive)
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James said: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.
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.