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#1
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Need help identifying components on Tachometer board
Pulled my non working tachometer amp. Smelled magic smoke and dug deeper.
Can anyone tell me what this burt part is? ![]() Sent from my iPhone using Tapatalk
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Current: 16 E400 4Matic 91 300E 4Matic - 2nd car 83 300D Past: 06 E350 4Matic 87 190E 2.6 - 1st car Last edited by m5mulli; 11-15-2020 at 05:03 PM. |
#2
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![]() Sent from my iPhone using Tapatalk
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Current: 16 E400 4Matic 91 300E 4Matic - 2nd car 83 300D Past: 06 E350 4Matic 87 190E 2.6 - 1st car |
#3
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I have seen precision wire-wound resistors which are in a package with end caps like that. They are usually coated with plastic, which likely burnt away. But, various 2-lead devices (resistor, inductor, capacitor, ...) might use the same "packaging". At least that is true of 3-lead devices (IGBT, MOSFET, Vreg, ...). See if you can measure a resistance, with it out of the circuit. A wirewound resistor might have overheated, but not been damaged.
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1984 & 1985 CA 300D's 1964 & 65 Mopar's - Valiant, Dart, Newport 1996 & 2002 Chrysler minivans |
#4
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It’s burned through. I found a circuit diagram yesterday and it looks like it is a 33ohm resistor that is directly off the 12v input pin.
I don’t exactly know the current draw so I ordered a few sets of resistors with different wattage ratings. We will see... Sent from my iPhone using Tapatalk
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Current: 16 E400 4Matic 91 300E 4Matic - 2nd car 83 300D Past: 06 E350 4Matic 87 190E 2.6 - 1st car |
#5
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Well. Resistor has been replaced but that still didn’t help. While I had things appart I decided to check the output voltage from pin 3 with the amp installed and the engine idling. It’s outputting about 400-500mv and goes up as I rev the engine. So that’s a good sign but I am not sure if those ranges are correct.
I guess the next thing is to pull the instrument cluster and see if the tach is even connected Sent from my iPhone using Tapatalk
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Current: 16 E400 4Matic 91 300E 4Matic - 2nd car 83 300D Past: 06 E350 4Matic 87 190E 2.6 - 1st car |
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