MyFirst5000
01-19-2004, 11:01 AM
<center><img src="http://pictureposter.audiworld.com/65520/tacho_ic_xa.jpg"></center><p>
See http://www.sjmautotechnik.com/instrument.html#speedo shows you how to pull the cluster but i was told by a dealer my tacho was DOA and unrepairable! Since i'm an electronics engineer i spent some time on it myself and after a couple of hours investigation using normal repair techiques found a resistor had 'gone high' in value! Should be 1300ohms, not 103k. Resistor is physically positioned directly off pin one (but can't recall if its connected, i think not) off the tacho ic type ITT V 3003-393. NOTE: There's no data out there about this chip! Found ignition pulses were arriving at the chip but it was not oscillating on it's crystal. Just posting this for the database and anyone else whose tacho is dead.
See http://www.sjmautotechnik.com/instrument.html#speedo shows you how to pull the cluster but i was told by a dealer my tacho was DOA and unrepairable! Since i'm an electronics engineer i spent some time on it myself and after a couple of hours investigation using normal repair techiques found a resistor had 'gone high' in value! Should be 1300ohms, not 103k. Resistor is physically positioned directly off pin one (but can't recall if its connected, i think not) off the tacho ic type ITT V 3003-393. NOTE: There's no data out there about this chip! Found ignition pulses were arriving at the chip but it was not oscillating on it's crystal. Just posting this for the database and anyone else whose tacho is dead.