I recently was in touch with Nissonger for a problem with my Smith mechanical speedometer.
The cost for a repair is $175 and approximately 4 weeks turn around. For an extra 50 bucks you can get it expedited and then work done in a few days. shipping is extra ....
They want you to send the reversing gear attached to verify it is engaging properly and not part of the problem.
Instrument rebuilding:
Nisonger Instruments :: the exclusive Smiths U.S. Warranty & Service Center since 1949
Shippping instruction:
Nisonger Instruments :: the exclusive Smiths U.S. Warranty & Service Center since 1949
Hope this helps,
Richard
Exact 427
Austin TX