Getaway No Ball Start

Arkansaw1983

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Dealing with a Getaway:

From Marvins Manual:

Switch Circuit problems and potential solutions.

Game comes up, but accepts no coins and won't start a game.
Check fuse F115 on the power driver board. Check switch #13, the start button, on the cabinet. The white-orange and green-brown wires must be connected to the switch blades. Check CPU connector J206, J207, J208, J209 for contamination. Check U20, pin 1; it should be high and pin 18 should be low. Check U18 pins 5, 2 which should be low. Check D5.



The speaker squaks when you hit the credit button to start.

Following Marvins repair manual, it looked like U20 and U16. They are located below the battery and were corroded. I replaced those two pins and took the battery pack off the board and mounted it remotely. That did not solve the problem.

U20 – 18 Pin ULN2803A - 5162-12422-00
U16 – 14 pin LM339 -5370-12272-00

What does it mean when Marvin says, a pin should be "high" or "low".

Thanks gang.
 
Which two pins did you replace?

High means when looking at the particular pin with either a DMM or Logic Probe you see the "state" go high (1). That means in most cases that current has changed state from off (0) to on (1).

Low is just the opposite, current changing state from on to off.

If U20 and U16 are corroded, you should replace both chips. If they are socketed on your board, great just clean the area and replace. If they are not socketed, then you have to desolder the 2 chips, install a socket then replace the chips.

What errors are you seeing when you bring up the test report? Look at the switch level or switch edge test and see if the switches are working, stuck on, etc.
 
To expand a bit on the "High" and "Low", that's what the 5v power is for. High means a circuit is turned on, and should have 5v through it. Low means it's turned off and should have 0v going through it.

It all goes back to the 1's and 0's of binary.

-Hans
 
I wouldn't use "on" and "off" when referring to high and low logic levels. It could confuse things because there are examples of low meaning something is "on" and high meaning that something is "off". It's just high or low. One or zero in binary. You could say "on" or "off" but like I said it confuses things.

The thresholds are usually something like:

Low = 0V-0.8V
High = 2.2V+
 
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