Wurlitzer 2300S Playrak registering too few credits

I'm having some issues with the Playrak on a Wurlitzer 2300 registering too few credits. This doesn't happen all the time, though it's pretty much 50/50 as to whether a quarter gets you the correct four credits, or registers only three.

What appears to be happening is that the accumulator wheel is bouncing back upwards after hitting 4 credits on the stop lever, and during the bounce, power to the solenoid/magnet that adds the credit is removed and the accumulator wheel is left sitting in the 3 credit position. I have tried some white grease to dampen the action of the mechanism and reduce the bounce, but that hasn't really helped.

I have a copy of the service manual and the troubleshooting section seems to suggest the TR-1 relay could be releasing too early. Suggested actions are to replace 20 mfd capacitor across TR-1, so perhaps the mechanical bounce is to be expected, and the accumulator wheel just needs longer to settle. Unfortunately, the schematics in my copy of the service manual are nearly unreadable, therefore I have no idea where this capacitor is located, or if I'm even chasing the right component. I don't suppose this is a problem that any of you chaps have come across before?

Are you sure that is a 20Mfd across the TR-1. the credit units schematics I have from that era show a 150Mfd:

http://s1192.photobucket.com/user/Rob-N ... ort=2&o=65

http://s1192.photobucket.com/user/Rob-N ... 0.jpg.html

http://s1192.photobucket.com/user/Rob-N ... 1.jpg.html

Rob/NYC

Rob, your schematics are a million times clearer than mine, thanks for sharing them. I got the 200mfd figure from the troubleshooting section of the 2300 service manual, but I can't say as to what value is shown on my schematics. Hopefully there will be some value printed on the old cap, but I'm still none the wiser as to where it's actually located! I slid out the playrak a couple of hours ago and couldn't see anything obvious in there.

Sure, mechanical system such as that would be subject to bounce-- I would assume the 20uf cap is soldered to, or very near TR-1 ??
Ron Rich

I looked in my old shop binder at the W2250 schematic a -no R&C across TR-1:
http://s1192.photobucket.com/user/Rob-N ... rt=2&o=132
http://s1192.photobucket.com/user/Rob-N ... rt=2&o=133
There is no depiction of a resistor and cap in the line drawings either. I do recall seeing a large cap in a Playrak, but obviously a change was made. The little ring under the relay symbol denotes that it was a slugged relay meaning that copper rings are added either above, or below the coil to cause a delay in the armature action.

At this point, I would treat the problem as mechanical and look at the action.

Rob

Gents,
Ah-ha--I have developed a theory, from what has been written here ("nice" way of saying "I'm guessing" ?)
Perhaps, WurliTzer found this problem, and corrected it by adding a cap ?--Might check out a schematic of a 2400 Playrak ??
Ron Rich

Thanks chaps, I'll take a look at the Playrak again later this week and see if the mystery capacitor is fitted. As you say, perhaps it's mentioned in the service manual as a retrofit, even though that isn't explicitly stated.

If it is a mechanical issue, I think the bounce may be possible to remove by placing a small rubber pad on the stops. It'll be a question of how thick a cushion is acceptable, which will no doubt be found through trial and error.

I'll let you know what I find.

Ok, so I think I have this one figured out now. As you said, Rob, it was a mechanical issue. Taking a closer look, there are a couple of springs missing from the hub and lever/lockout assembly. As soon as the coin magnet triggers, it looks as if there are a couple of catches that should hold the release levers in place, allowing the credit accumulator to settle. When a selection is made, the catches are disengaged by the driver pin on the cancel wheel.

One interesting thing is that the catch for the quarter pricing mechanism (yellow arrow) is stuck way back, whereas the dime/half-dollar catch is free to move. I haven't tried to release it yet, but hopefully it will just be a case of loosening the nut on the top right of the picture. The real challenge is going to be in finding a couple of suitable springs, as anything with too much tension is going to put a lot of extra stress on the cancel solenoid.

Just a quick update for anyone else that should ever have this problem; I found a 20x3.5x0.2mm expansion spring a perfect replacement for the missing originals.