Bally 5500 Double Jackpot 777 - Change Button adding Credits(First Time Poster)

[heggy18]

Hello,

TLDR : The red "Change" button only adds free credits.  Looking for insight on disabling this.

First time poster, and first time slot machine owner.  I bought this machine a week ago.  Everything is working great.  Besides my "topic post" concern, the bill validator does not work and was understood at the time of purchase.  For the life of me, I cannot recall the Change button (adding credits) prior to my family get together over the weekend.  At the party, all of a sudden my nephews were adding free credits without any quarters.  Completely possible the machine was already set up like this at the time of purchase, but I do not recall.

Myself, nor my nephews, have done anything inside the machine. 

I have been scouring this forum for related posts, but the few I have seen regarding "free-play" or what not, did not have much information.  I came across a post that mentioned possibly the "Change" button being wired into the pseudo switch on the coin optics.

I'm still trying to learn the lingo, parts, and what to look for.  If anyone has encountered this, I would really appreciate some insight.

[Pinballwizard55]

Some dealers rewire or install an additional part to enable free play so that the game can be legally transported across state lines. it should be reversable. The wizard.