seeing as it's running ''sweet'' doesn't apparently have any other issues other than an annoying flickering light and an unstable idle
does the OP really want to be pulling it apart ?
I've got a few of these - good for what they are but only to be used for indication
you'll not see any of these with a calibration sticker on
DIGITAL LCD MULTIMETER VOLTMETER AMMETER AC DC METER OHM CIRCUIT TESTER | eBay
check none of the windings are open circuit before you get too involved, they tend to overheat and burn out - if they have you now have a new door stay
the fact that it might well have had a shed load of money spent on it doesn't means it's worth a shed load - it's just a SIII
It's probably quite a good ride - but not 6K nice