996 (98) mech speedo is fixed on max!

[911Fiddler]

The digital speedo works ok.
The mech one sits at max all the time. Even when shes switched off.

Anybody know the cause before I start dismantling?

[996TT02]

Is it really mechanical i.e. cable operated, or do you just mean "analog"?

If mechanical perhaps the pointer return spring has failed although in that case it would probably sit just about anywhere unless it went to and basically just fell by gravity to max position when you drove the car the first time it happened, if electrical, then the problem is probably, ahemm, electrical... bad signal or some form of failure of the unit or some connection.

[528Sport]

what happens if you disconnect the battery?

Sounds like an electrical fault, the mechanical speedo is electronic driven ie no old type cable as such

Might even be worth taking the plugs out the instrument cluster to give it a full reset

[911Fiddler]

Cherrs.
Battery reboot doesn't. Fix it.
Agree it's electronic. If I'm lucky it'll be a dry joint or a seized cog perhaps. Think I'll aim to transplant speedo electronics, eBay here I come....