IPDB says Stern Playboy is Whitestar system. http://pinwiki.com/wiki/index.php?title=Sega/Stern_White_Star_Repair

Section 4.3 might be helpful.

Do you know how to use a multi-meter? Can you read schematics?

It sounds harder than it is. We can help. Take some pictures of your boards and post them.

On your driver board you should find your adjustment pot R116. Near it you'll find R114, just below your +5v LED.
Measure the voltage on the bottom leg of R114. If it's less than 4.85v try and raise it using the adjustment pot R116.

Let us know what you find.

Next step is get that backbox open and post a picture of the boards. Post a picture of your multi meter.

Look in your manual, the schematics for the driver board should be labeled. On that schematic, find R116. Then find it and R114 on your board. Take a picture of them. Then we'll figure out how to set your meter and test the +5v.

In post #6 you said, "1500 with original manual..."

What's the deal?

Did you check inside the coin door for the backbox key?

With the game on, test the bottom leg of R114 for DC voltage. If it's less than 4.85, turn it up using R116. I've circled R114 and R116 in the attached photo.

Watch this video to explain how to use your multi-meter.

PlayboySternPowerDriver_(resized).jpg

If your gf isn't into pinball it's time for her to move on. To Austin. Send contact info ASAP.