Why would a machine start spitting out quarters after vending

[PrimetimeMT]

Curious why this would happen.  Randomly, the machine will vend, then spit out a bunch of quarters.  For example.  a person puts in $.50, selects an option, it vends, normally you hear a "clicking" sounds relating to it counting I assume.  In this instance, it spits out, say $11 of quarters.  Nothing else seems to malfunction.  My machine is an old LektroVend VS99.  I'd replace a part but what would I look to replace?

[orsd]

Check for burned out or flickering lights in or near the machine.

[AZVendor]

You probably have a dim or burned out florescent bulb in your machine or near it, like in the ceiling, causing interference as the bulb tries to light.

[PrimetimeMT]

Sorry for the late reply here.  I didn't get the normal notification on it.  Anyway.  I was having an issue for quite a while with the light being dim and going out in the machine. I replaced the ballast and "starter" in the machine and have not had an issue since.  It would also have the front panel display random dollar amouns from time to time and you could hit the change return and get that amount to drop out in quarters.  That issue was also fixed when I did the ballast and starter.  There is an old refrigerator right next to the machine., and it is in a warehouse type setting where there are flourescnet lights, they are all about 8 feet above the machine but now that you mention it, I see one of them is burned out.   I'll see if maintenance can replace the light(they won't let me do it) and see if the problem goes away.  You guys are geniuses!

[PrimetimeMT]

Looks like replacing the light above the machine fixed the issue!  Thanks again!