Reply to "Reverse board won't go forward, bad transistor or some thing else?"

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Originally posted by stan2004:
So to be clear, with no motor connected, using Diode mode you measure each NPN between pins 2-3 (and then 3-2 backwards) and in each case you measure 0.0V (like when you touch the test leads together).

To be precise it's 0.6V black on 2, red on 3; and then 0L red on 2, black on 3

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You do the same for the PNPs and in each case (pins 2-3 and 3-2) you measure "OL" or whatever the Fluke says when the test leads are not touching anything.

Yes

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And if you measure, say, that diode on top of your pic of the burned K-line board you measure 0.7V (or so) in one direction and "OL" in the other direction.

YEs

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Let the games begin!

Indeed

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Originally posted by Norton:
Disclaimer: Peal off the label and try and determine if its 555 type or microcontroller.

Pete

Here's the numbers 12C509A 04/P4K6 0351

quote:

Originally posted by Norton:
You could verify if its that chip if you have and identical board. It appears to be in a socket so just swap them out.
Pete

I do have an identical board. I'll tear into the engine that has it tomorrow and report back.

quote:

Originally posted by GGG:
You can test the moc for continuity with a 5 volt test signal, but you will need to lift pins.

DO you mean it will need to be disconnected from the board before I can do the continuity test?