does any one have any info about rebuilding early 240z tachs (4 wire). wiring diagrams, comin faliure points, tips, or any thing. i have 2 tachs with 2 different problems and i hope to make one good tach.

tach 1: goes to 9000rpm any time the key is on

tach 2: nothing happens

I have an early tach schematic I will post after I get it scanned. It’s just a very basic two transistor astable (one-shot) multivibrator circuit that drives the meter coil. The transistors are type 2SB189 (PNP 25V 250mA). Looks like you can still get them: http://www.ceitron.com/semi/ceitoshiba.html

Steve Golik

Smoky Mountain Z Car Club

Knoxville TN

1970 240Z

1974 260Z

1979 810 Hardtop

"30 years of Z car ownership"

Hey Steve, glad to see another fellow 810 coupe owner over here. There aren't many of us.

Here's the 240Z tach schematic....

thanks hopefully now i can fix atleast one of them