e type rev counter

[glenmere15]

can anybody help with this-
everytime i take my e type out (series 2) the rev counter works fine for about 10 minutes
then packs in altogether this is baffling me somewhat because it works fine when it is working
thanks.

[RW774]

Check the coil impulse wire at the ignition coil is intact and the terminal is not broken, otherwise its instrument out for overhaul