Hi all,

I purchased a MGOW and once I got it home I discovered it had some issues.
One being that I cannot get into the self test. I have checked continuity of the button itself and its functional.

I have read the Gottlieb System80 service manual pdf and it mentions checking the "Play/Test switch isolation diode on bottom board".

Where is this located, and how do I test if with my DMM? Has anyone had a similar issue? And if so what else can I check to determine the cause of the Play/Test button not registering?

I found the strip. I checked the diodes and got a reading back of .235 or .240 for all. I attached an image. Assuming this is the right strip.

Still not working. Is there a way to jump someplace to bypass the switch so I can enter diagnostics?

20161113_175449 (1) (resized).jpg

Thanks for the leads guys. I traced the wiring back to the cpu board and to Z14. I went ahead and ordered a new SN7400N IC and will see if replacing this fixes the issue. Will keep you all posted.

Reading only in one direction.

Fixed the problem. After much tracing, one of the 2 wires for the switch has been broken right where the bend is for the coin door hinge. At some point in its life it must have had the coin door swung open waaay to far. Wire looked fine, but copper was broken. Ended up using a tone generator to find the break. Cut out break and spliced back together. Works like a champ now.