Just getting an idea of how many people are looking to take up this mode kit.
The mode is two ball multiball, no undoable playfield changes , suitable for all gottlieb recel machines
from the late sixties to late seventies.
Est. cost $300 us diy kit

I'll post a video of it in action . Not sure its a secret but if demand is high enough Marco specs will sell the kit.

HERE'S A SHORT FILM SHOWING THE POSITIONS OF THE BALLS AND THE LAYOUT OF THE TRAY.
METAL WORK IS A BEND ON THE ORIGINAL REAR TRAY AND A POST TO TAKE UP THE 20MM GAP.
THE HARDWARE IS A SLING ASSEMBLY TO FIRE THE BALL AND A TARGET ATTACHED TO A SOLENOID FOR THE GATE .
I HAVE PUT THIS UNIT INTO SEVERAL PINBALLS WITH A LOT OF SUCCESS ,ITS JUST A VERY ORGANIC DEVICE .
THE MACHINE VIEWED HERE IS A BALLY GRAND TOUR WHICH I CHANGED THE TRAY OVER ON.IF ANYONE HAS PLAYED THIS MACHINE YOU'D KNOW YOU CAN PLAY A WHOLE GAME WITHOUT GETTING BAT ON BALL .
THIS IS NOT FOR EVERY MACHINE , YOUR LIMITED TO MULTIBALL SHOOTING LEFT TO RIGHT AT AN ANGLE OF ABOUT 20 > 30 DEGREES FROM BETWEEN THE FLIPPERS ( MR GOTTLIEB LEFT PLENTY OF ROOM THERE THOUGH ).BUT IF YOU'VE GOT A MACHINE WITH A KICKOUT ON THE PLAYFIELD OR A 5000 POINTS HOLE IT CAN BE A LOT OF FUN ...

Firstly thanks for all the input, I am only at this point after expressions of interest in this mod.
Everyones concerns about hacking into playfields are understood and its mainly the gate for retrigger that is a problem if a boo boo is made ( don't do it ),But as stated previously there would only be one multiball per ball available. This is not a cosmetic area of the machine and rarely even got a lick of varnish from the maker . If you compare a unmodded tray you'll find the shooter is actually outside the original guts of the machine. As a result the mod is totally reversable.
Trying to answer why pay $300 I thought that would be obvious, the new parts the circuit the stick on templates the literature on adapting to a variety of machines the cut the retailer wants to take my time etc ....really ? If you have the ability and the parts to do this yourself GO FOR IT ! thats why I'm putting this post up the video shows the locations required,+ I am happy to help if anyone has more questions.
So it's totally clear I love old EMs and I'm not a huge fan of the later model machines which seem more like a gun filled with plastic and metal has been fired at a playfield, but lets face it multiball is fun! That's no reason to carve up a perfectly good game though.
As far as wiring is concerned there are two end of ball switches for single multiball and a relay if the retrigger is employed.I generally add a seperate 12v aux supply if multiball is to be controlled by a more elaborate means to isolate it from the machine ,say position 5 on a (ss) decade counter or all targets down switch on a target bank.This allows the use of much cheaper and more reliable 12v relays and solenoids capable of constant activation without the need for hold coils( part of proposed kit ).
Like I said this is not for every machine or everybody to be honest I expected far more abuse for proposing this, but if you want this mod and only you'll know which machine NEEDS it the mod is not that hard to do.
Hey I put mag wheels on my car but its still a Holden Torana.

_{Post edited by kaboom : detail}

HERE'S A VIDEO OF A RECEL MASTER STROKE ( WHICH IS A GOTTLIEB IN PARTS CONFIG ) MODDED FOR MULTIBALL .
WHEN I GOT THIS MACHINE IT HAD BEEN STORED UPRIGHT AND WATER DAMAGED AND SEEMED TO BE A GOOD CANDIDATE FOR CONVERSION. IT NOW HAS SOLID STATE BONUS , LEFT OUTLANE BALL SAVE ( ALL TARGETS DOWN ) A KICKOUT HOLE IN THE BREAK AWAY LANE FOR 10,000 OR 100,000 WHEN LIT AND OF COURSE MULTIBALL.
MULTIBALL IS TRIGGERED BY THE 50,000 RELAY VIA THE MOTOR.
BALL SAVE IS VIA A CHANGEOVER RELAY WHICH CHANGES THE ROLLOVER FROM 5,000 TO 50,000 FOLLOWING THE INSIDE RIGHT RETURN LANE.
I DIDNT GET SPECS ON THIS BALL THOUGH ....OH WELL NEXT BALL