mjr

thanks for trying - much appreciated, ST didn't even bother replying to my query! how does one go about checking the operation of an unidentified chip? my current knowledge of electronics is such that i don't even know if this is a rhetorical question or not! anyone got any suggestions? thanks mjr

i am currently fault finding a VDO controller for the central locking system of a mkIII volkswagen golf, though having little experience am finding it quite a slow and painful experience! with the help of various websites, i have been able to identify and obtain info for all but one of the ics in this unit. the offending chip has the ST logo and the follwing numbers: 6N9 859 740-01 G993A9444 it's a 10 pin DIL and i think may be CMOS or TTL. all the web based resources that enabled me to identify the other chips drew a blank for this one and the manufacturer web site wasn't of much use either. I suppose the problem is that it's either an application specific chip or obsolescent (the ECU is about 10 years old). Any thoughts about this or general suggestions about other ways to identify chips would be very gratefully received as it's starting to drive me potty, as i'm pretty sure that this is the part that's faulty. thanks malcolm