a) Start by looking at ALL of the diodes and ensure they are the right way round.
b) Check that you fitted the mica insulators under Q9 and Q12 on the heatsink
and that they look ok.
c) Now you can plug it into your Stim and measure the voltage on the 40 pin
connector U1:
Put the -ve probe of your voltmeter on pin 32 of the 40pin connector (U1) Note,
this is WITHOUT the MS1 or MS2 microprocessor in place!
Put the +ve probe onto pin 20 (Top pin right side)
Ensure you read 5V (+- 0.1V)
d) Keep the +ve probe on pin 20 and move the -ve probe to pin 19 and pin 2,
ensure you have 5V on the meter for both measurments. If its OK goto stage 25.
e) If you don't get 5V then put the -ve probe on the 0V on the proto area and put
the +ve probe onto the left pin of U5 (top left hand side on heatsink) check the
voltage on the meter, it should be 12V (9V if using a battery) if this isn't there
then you have a stim/battery problem as the ECU isn't getting any power. It could
also be a diode in the wrong way round, so check D10, D11, D12 and D13!
f) If they are all OK then check the mica insulation on Q9 and Q12, with an
ohmmeter (mulitmeter) put one probe on the metal heatsink and another on the
metal tab of Q9 and Q12, you should read 300+ Ohms. If you read less then you
have a short, remove the insulator and fix the issue with a new one.
If you have any smoke then its likely you’ve put a diode in the wrong way round,
this will mean finding it and fitting a new component. Once any component
smokes it is no longer any use!
