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1991 Pontiac Sunbird Electronic Speedometer PCB Board ICs


reveng

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Have a 1991 Pontiac Sunbird LE 3.1 V6 with an analog display speedometer that is no longer operational. Have verified the Vehicle Speed Sensor (VSS) and it is outputting a very clean sine wave as input to the Engine Control Module (ECM). The ECM is outputting a very clean square wave to the electronic speedometer cluster as input to the speedometer PCB board. So I am in the process or reverse engineering the PCB board which is not a problem with the one exception being the ICs on the board. Have not been able to find the datasheets for the ICs on the PCB board and was hoping someone on this site may be able to provide information on the ICs or point in the right direction to find the information. Attached is a picture of the electronic speedometer PCB board and the ICs I am trying to identify are as follows:

 

IC1: 9907A

CS9101J

 

IC2: 1681B

CS9048J

 

RA1: D-1

 

Thanks,

 

post-8771-143689134763_thumb.jpg

 

 

post-8771-143689134652_thumb.jpg

Edited by reveng
Added RA-1 Laser Etched Resistor for Reference
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RA1 = calibration resistor for the speedo.

IC1 = the frequency to voltage converter for the magnetic speedo drive, IIRC. or at least, that's how it's used on the GP UB3 clusters.

IC2 = not 100% on this, but schmitt trigger(IIRC) or comparitor to drive something on your board, possibly a "coolant hot" light or something along those lines.

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Have a 1991 Pontiac Sunbird LE 3.1 V6 with an analog display speedometer that is no longer operational. Have verified the Vehicle Speed Sensor (VSS) and it is outputting a very clean sine wave as input to the Engine Control Module (ECM). The ECM is outputting a very clean square wave to the electronic speedometer cluster as input to the speedometer PCB board. So I am in the process or reverse engineering the PCB board which is not a problem with the one exception being the ICs on the board. Have not been able to find the datasheets for the ICs on the PCB board and was hoping someone on this site may be able to provide information on the ICs or point in the right direction to find the information. Attached is a picture of the electronic speedometer PCB board and the ICs I am trying to identify are as follows:

 

IC1: 9907A

CS9101J

 

IC2: 1681B

CS9048J

 

RA1: D-1

 

Thanks,

[ATTACH=CONFIG]13346[/ATTACH]

 

[ATTACH=CONFIG]13358[/ATTACH]

 

RA-1 Laser Etched Resistor for reference

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