reveng Posted July 17, 2013 Report Share Posted July 17, 2013 (edited) 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, Edited July 20, 2013 by reveng Added RA-1 Laser Etched Resistor for Reference Quote Link to comment Share on other sites More sharing options...
Psych0matt Posted July 17, 2013 Report Share Posted July 17, 2013 Paging Saar Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted July 17, 2013 Report Share Posted July 17, 2013 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. Quote Link to comment Share on other sites More sharing options...
reveng Posted July 20, 2013 Author Report Share Posted July 20, 2013 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 Quote Link to comment Share on other sites More sharing options...
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