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Odometer problem - burned resistor on circuit board

 
Old 07-09-2019, 05:46 PM
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jas79
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Default Odometer problem - burned resistor on circuit board

I've got a broken odometer on my 1986 Euro S. I replaced the odometer gear some years ago, and after that the odo worked fine. Now it died again. I guessed that iy was a gear issue again, and took it apart. No broken gear, and it counts fine when rotating the mecanism. There must be a electrical issue in the odometer. The speedometer works, so the impulse sender on the differential, the flexible circuit board, wireing etc must be OK. The problem must be in the odometer instrument. I found this excelent thread about problems i the instrument. It┤s only one problem with it. The pictures are missing.

https://rennlist.com/forums/928-foru...rs-intact.html

I soldered the step motor out of the board, and checked it according to the instructions. It works perfectly. I found one burned resistor on the circuit board. In #17-18 in the thread they talk about checking a resistor, that should be 22 ohms. Which one on the board is that? Anyone got the pics from that thread?

Anyone know the value on my burned resistor? I soldered it out of the board, and it is about 48 ohms now. I don┤t know if it is the correct value, but it neeeds to be replaced. Maybe some other components too? It is the UAF2115 chip.

Any inputs and ideas are welcome!

/Mattias

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Old 07-09-2019, 06:26 PM
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Majestic Moose
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According to this thread it should be 33 ohm and it may have burned out due to a shorted capacitor.
https://rennlist.com/forums/928-foru...r-failure.html
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Old 07-10-2019, 04:48 AM
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Thanks for that link, very useful!

I will report back after replacing the resistor and capacitors.

/Mattias
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Old 07-12-2019, 02:15 AM
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I have the same burned resistor on my 85. I have no speedometer or odometer at the moment. It would be nice if someone sold just this circuit board, vs having to buy a complete speedometer assembly
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Old 07-12-2019, 06:11 AM
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I sent in my speedometer to Specialty Gauge and he replaced the board.

Cory Shepherd
Specialty Gauge
8110 Weatherwood Ct
Unit 202
Manassas, Va 20109
703 402 4008
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Old 07-12-2019, 12:30 PM
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Maybe they will rework amp gauge too. Mine pegs out. Stan and I measured 12 volts. Must be something similar.
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Old 07-12-2019, 06:59 PM
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Report after repair:

I replaced the 33 ohm resistor, the 47 and 100uF capacitors, and now the instrument works perfectly!

I checked the removed components, the 47uF capacitor was broken but the 100uF was OK.

THANKS TO ALL HELPFUL RENNLISTERS - this forum is fantastic!!!

/Mattias
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