You're close but not really going to get very far!
I repaired fruits for over 18 years.
There are ways to beat the machine the majority involve a little knowledge and a lot of luck.
DRILLING - Drill a hole into the R.H. side of the machine level with the payout mech, and hope it's not been protected. You may then be able activate the payout unit if you have the right shaped tool.
DEVICES - I have seen devices made which will allow someone with a little practice to fool the payout counter into paying out way over the actual winnings banked, there is a skill to this fool it for too long a period and the machine will alarm.
SPARKING - piezo electric sparks worked about 15 years ago by pulses being transmitted along the credit loom, aerials and plenty of grounding to a good earth solved it short term, extra software alarms were added in newer models, I wouldn't suggest trying it these days.
LOADING KEYS - sold on ebay for £3 - £15 all they allow is for you to look into the machines electronic meters and see Hopper/Tube levels current % and aiming %, if the hopper/tubes are full or current% is lower than aiming% then the machine may pay out over the odds to return to its preset levels, this can occur over £10 - £200 so don't spend what you can't afford losing.
SOFTWARE BUGS - this is where you can make big cash, do a search for info on gliches in software then target the specific machine. Any machine supplier who doesn't update the software when a bug is discovered deserves to be hit hard, may as well just leave the machine open so you can help yourself look at places like
http://www.thegambler.org
STRIMMING - garden strimmer wire formed into a loop could be used to hit the microswitch that supplies signals to the credit lines, again now out of date as nearly all coin mechs use Opto sensors and electronic mechanisms, may find the odd video that can be done.
Smash and Grab - this is the most common way that machines are beaten. The Cabinates are generally made of chipboard or MDF a well place wrecking bar can pop open a machine in seconds, I know of some who could do this so cleanly they would help themselves then replace the doors and come back a few days later for seconds, anyway this is illegal and anyone going this route doesn't need any help from me.
There are many other machine specific tricks that are all out of date now, Coca cola, silver foil and foriegn coins glued together are a few that come to mind.
In General understand that this is big business and they have security depts. watching for patterns in takings/ interest in specific types of machines. The majority of machines have data monitors that phone head office on a daily basis flagging up odd % runs and machines are removed as soon as anything pops up.
As I say the only legalish way is to find machines with software faults that haven't been updated, arm yourself with the knowledge and then fill your boots. Ignore Service stations and go for small arcades.
Apart from this
The only consistant ways of earning from fruits is to buy an arcade and lie to the taxman about how much you earn!
Remember spend only what you can afford to loose.