Hi Andrew,
Thanks for reply.
So I've just had a panel remove-a-thon and located the sensor board and the other one you mentioned in the left arm. Nothing appears loose up there but I disconnected and reconnected the stiff grey flat wires joining them together.
The wires then dive down the left arm and reappear in the base. There are two connections at the bottom end of these wires that were not attached to anything. One (6 pins) may have come from the board directly under the front panel but the other one (9 pins) doesn't seem to go anywhere. When I connected the 6 pin end it was no different. Same start-up error message
I could not be sure which part is the transister you described.
Addit: FIXED!!!
I typed "Meade LX200GPS circuit" into google images and this image popped up
http://www.cloudynights.com/topic/91...ng-hard-stops/
Turns out three loose connections, so obviously pulled out somehow. I suspect it may have occurred when attching the scope to the tripod in the dark one night.
So thanks for your help but seems to be good now.