Hi

Reflex DC, dont see many of those around any more.

E102 = Error signal from servo electronics.

Faulty servo unit OR the emergency stop has been activated.

Have a look at the contact block on the back of the emergency stop switch, sometimes these do play up & cause error codes to be flagged up.

Remove the armrest cover ( wing nut & unclip the lever for console ) have a look at the grey transistor panels, see what led's are showing on the traction one.

While the cover is removed check all the main system fuses.

Also I take it the battery is in good condition?

I've not touched a Reflex DC for years, they never normally give much trouble.