Can't figure out what the heck is wrong with speedometer

[ohavro]

Bought an 86 last week and the speedometer/tach doesn't work- lights up, though. I drill spin the cable and the speedo mph works. So I assume the problem has to be the speedo drive on front wheel. Have extra one, so I replace it. Nothing appears to be damaged.
Still doesn't work.
SOMEBODY SAVE THE N00B

 

[MaxMidnight]

If you disconnect the cable at the speedo end and spin the front wheel you should see the inner turning.
Assuming the end is still squared and the speedo(s) don't work (needle AND odometer) the n you have two Donal Ducked instruments.

If the cable doesn't turn then either the cable is broken or you have a problem with the cable drive on the front wheel.