Gremlins

Graham, she is calling out to you for more attention.

After 85 years I guess it’s to be expected that faults show up in the most unexpected places. My 810 had recently developed an intermittent slow or occasional refusal to gear change. After a lot of head scratching with the gearbox cover removed, I found that the blue wire to the shift solenoid had only 3.6v, marginally enough to shift.
The rotating segment of the gear selector switch was found to have high resistance between one contact and the circular bridge on the reverse side, a spot of soft solder and the old girl shifts like it’s 1936 again !.