Bench testing an odometer

1993 245 with the K39200 speedo.

I’ve had an intermittently functioning odometer since i replaced the gears. I made sure all old broken gear pieces were removed. The odometer would usually not start during the first few minutes of driving in then all of a sudden on the highway it would start functioning. I also noticed that if I pulled the cluster out and pushed the speedo connection in the odometer would function. However, it only seems to work for about half of a mile and then it stops working again.

I took apart the connector in the cluster that plugs into the back of the speedometer and I clamped the pins closer to each other in order to make a tighter contact on the back of the speedo. This did nothing.

I would like to know if there is a way to apply voltage or something to this speedometer outside of the car in order to bench test it and check for odometer functionality.

I seem to remember the speed signal being AC voltage.

Try shimming the two little screws at stepper motor. Mine became stuck if these screws were tightened.

Per Art, a 300Hz 250mV rms sine wave works with a '91 speedo. The '93 may read half the speed, but the test signal should be about the same level.
http://cleanflametrap.com/speedo.html

edit: here's an example using a smartphone and a wall wart: http://www.forums.turbobricks.com/showpost.php?p=5616393&postcount=12

So my odometer has been 100% functional after i fixed some weird circuitry that affected the temp gauge. No idea on the correlation but all i know is that the 4 pins where the comp board is, were not fully seated. I fully seated the pins and the green piece that holds them in place. Since then, temp gauge and odometer have been perfect. Weird.