Thread: OM617A Tach Amp
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Old 04-19-2008, 03:15 PM
techguy512 techguy512 is offline
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Join Date: Apr 2005
Location: Austin, TX
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Quote:
Originally Posted by pawoSD View Post

Others have said its not possible for the pickup to fail.....
It is completely possible for the pickup to fail. Or the cable to fail. Or the solder joints at the sockets to fail. I talked to one person who had the pin at the pulley crash into the pickup and take part of the face off. New pickup fixed it.

The other issue that you might check into is bad wiring between the amp and the gauge. This new amp has the self test feature to help eliminate that as a cause of problems.

Here are the pin assignments to the pickup. The numbers are shown on the socket connector on the fender (after you unscrew the cap).

pin 9 is input from sensor
pin 8 is sensor return (gnd)
pin 7 is sensor cable shield

Get a DVM, and put in resistance (ohms) mode. You should get the following readings:

pin 8-9 80 ohms (+/- 20 ohms)
pin 7-9 infinity (open)
pin 7-8 infinity (open)
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