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Hello guys needs some help, my speedo cluster in my mercedes r129 isnt working so I checked the fuses they seem Ok, the OVP relay fuse is ok so I was thinking it could be the capacitors on the cluster but is there a way to check them before I replace them all help is appreciated in advance
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I'm no expert on this but my reasonably good multimeter will only test very small value capacitors and they need to be out of circuit.
I'm sure other testers will have different abilities but testing caps, especially on a board, isnt too simple.
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fad
Posted a lot
Posts: 1,781
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You have to disconnect one leg of it in order to test. Once done, set your multimeter to read resistance on a fairly high range. Put the test leads on the capacitor (if electrolytic, match the polarity, electrolytic has a + on one leg) , it should read zero then slowly build to open circuit. If it doesn't, its goosed.
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You have to disconnect one leg of it in order to test. Once done, set your multimeter to read resistance on a fairly high range. Put the test leads on the capacitor (if electrolytic, match the polarity, electrolytic has a + on one leg) , it should read zero then slowly build to open circuit. If it doesn't, its goosed. For some reason I hadnt thought about just wanting to see if they are broken, I was looking at it as wanting to check their capacitance. I know they can drift, but broken or not broken may well be good enough in the op's case. |
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fad
Posted a lot
Posts: 1,781
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You have to disconnect one leg of it in order to test. Once done, set your multimeter to read resistance on a fairly high range. Put the test leads on the capacitor (if electrolytic, match the polarity, electrolytic has a + on one leg) , it should read zero then slowly build to open circuit. If it doesn't, its goosed. For some reason I hadnt thought about just wanting to see if they are broken, I was looking at it as wanting to check their capacitance. I know they can drift, but broken or not broken may well be good enough in the op's case. Yeah they can break down but its a good base test. Testing them properly is way more in depth and for the size the op will be dealing with its faster and cheaper to just replace them than bother testing in depth. |
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Thanks guys I will check the wiring on the cables going to the cluster if they are ok then it the capacitors that are gone also been told the capacitors could been blown so could be seen visually, ideally as mentioned would be easier to replace the capacitors also been told to try get close to the rating of the capacitors but higher if need be not lower as it will blow, hope to sort it will be testing earth and wires to the cluster to make sure it ok before opening the cluster also is there any company that could sort these out for me I seen a few videos on YouTube and seems straight forward but it's like riding a bike the more you think about it the harder it gets thanks again for your help
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fad
Posted a lot
Posts: 1,781
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Higher not lower or it will blow?
Think of a capacitor as a pressure accumulator. The pressure rating would be the voltage rating of the capacitor, the volume would be the value of the capacitor. You need as close to the "volume" as you can get but the rating is pretty arbitrary in a speedo, anything over 12v to be safe.
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Aug 17, 2017 23:12:56 GMT
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Just seen the capacitors 2 are 100 micro farad which one says 10v so believe the other to be the same but there's a big 470 micro farad which says nothing with (V), but on top it says 470/16 would this mean 16v but i seen some that are 470 25v and 35v would any off these be ok to use, thanks again for any help
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fad
Posted a lot
Posts: 1,781
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Stick em in and see.
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Looked on Merc forum and most say they replaced it with 16v but can go high but never lower so il try maplins thanks again guys
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fad
Posted a lot
Posts: 1,781
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Looked on Merc forum and most say they replaced it with 16v but can go high but never lower so il try maplins thanks again guys Before you do let me look in my parts bin. Might save you a few quid. |
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