Testing my 6803 mpu board to find why upper right slingshot solenoid is always on.
Power off to machine.
Fluke 115 meter set to diode mode.
Visually I can see transistor q17 and 4 others do not look the same as all other transistors in the top edge row. (The board is mounted with the top edge to the left side of the back box as this is a truck stop machine.) The 5 different looking transistors have what appears to be a 1/2 inch heat sink metal tab extending out vertically inline with the 3 pins to help you visualize this were as the others look like what you see in photos of this OEM board
So a comparison of all these
Q17 transistor probing top most pin to center base pin .0009 volts
Q17 transistor probing bottom most pin .264 volts
Other 4 non OEM transistors
Top most pin .364 volts
Bottom mostly pin .264 volts
So the question here is does this sound like I confirmed the problem correctly?
This is my first foray into owning and repairing a pinball machine.
I suspected this may be the problem prior to testing after searching and reading other 3806 topics and threads on this forum, as well as the pinrepair.com writeups and pin wiki.
My only electronics experience is from installing remote starters in autos for 30 years as well as wiring in relays for various functions in my past owned racecar.
Since buying truck stop a few months ago I have repaired the following.
1 Replace lower cabinet graphics.
2 Replaced upper flipper bushings that were both cracked
3 Sourced and replaced one plastic (found it in Germany) that I had to modify to fit as their template to manufacture has incorrect hole mounts and red lense diameter
4 Replaced Power supply board with swemmer electronics unit
To be done:
1 Waiting for delivery of out hole switch that has intermittent failure and appears to not be correct oem unit
2 waiting for delivery of 2 pinscore displays that took out the fuses on the oem power supply board (figured i would upgrade that board to just make the improvement and forget about it.
3 I found Fred Swemmers email address on his YOU Tube video so I sent him an email requesting how to buy his replacement 3806 MPU board since no one had one in stock. He responded and is making me one as I type this.
So I think i Might be off to a good start in learning how to make improvements and repair my first pinball machine. Your thoughts?