Simrad TP 32 tiller pilot problem

[kalanka]

My Simrad TP 32 was operating under light loads when it suddenly started to emit a squeak like a binding brake and then the piston stopped moving. Switching on and off has had no effect. The piston no longer rotates on its axis. The piston cannot be retracted.

It seems to me likely that there is a failure of the worm drive or similar. I plan to dismantle and have a look. Any advice or alternative diagnoses? Can such a failure be repaired? Thanks

 

[lustyd]

My experience of these is that before you test anything else at all, give the thing some good reliable power and test again. 10 out of 10 times my problems were corroded plug/socket. It never screeched at me though, which I'll admit sounds worse!

 

[kalanka]

Update: I have now opened the case. The toothed drive belt has come off the pinions. The squad was probably it rubbing on the moving parts. Has anyone had experience of replacing this belt? I fear that the belt has stretched and should be replaced but this looks as though it would require a substantial disassembly of the whole unit. Am I missing something?

I wonder also if shedding the belt is a symptom and not a cause. The pushrod (I call it a piston above) normally rotates to allow the end fitting to engage with the pin on the tiller. There is now no rotation but I cannot find a reason for this. The pushrod moves freely in and out if I manually turn the larger pinion that drives the worm screw.