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welcome to the Mad House hope you enjoy your stay as once you get hooked you'll be here forever. Have fun and join in the banter that follows. what fruit machine era's are you into as in what decade or is it all of them??

yeah! my record of every M1 board I have started to repair has been repaired and fully works is still intact! I think someone wanted to see a video of it working when I got it working! so here it is!

when theses machines are in arcades with loud music and loads of kids you would not here the buzz so much

on some of these machines you will get feed back noise off the lamps

it should be on the top left corner of the program card if its a t shape card i know if those volume pots go weak thay cause all sorts of crackel and fizzies

the onboard mpu4 volume pot is only used for mod 2 games

at least it is good the circuit diagrams are about for M1 tech! it may through up some strange things (in tons of boards this is the first time I have seen this fault!) but as least M1 is definitely repairable even if people hate it so much!!

are you sure the volume pot is not on the program cart?

odd though how the game software relies on the NMI being present but the test software doesn't!!! you would think they would make it that the test software also looked for this NMI signal as it is so important in testing a board! Again something it looks like maygay overlooked when the test software was developed!

well running out of ideas now! lol was just going round with a scope seeing if I could see anything different to a good board, knowing it booted fine on test software of course everything was fine! Quite by chance, i put the scope on pin 8 of IC7, there was nothing there. Now I quite expected that as this is the circuit above the NMI is the non maskable interrupt which I think I have spoken about in another thread, when the board comes out of reset the PAL chip sets the ENABLE pin high to 5v, this basically allows the waveform on pin 9 through to pin 8 which goes to the main CPU! the 12vMM is a 100hz full wave rectified (but no smoothing capacitor on it) which turns on transistor Q2, the collector of Q2 is a 100hz 5v pulse! a nice shaped pulse with nice steep sides! this waveform on the bad board was very low! not even making 2.4v! so was not passing through the gate in U7 as was lower than the gates threshold, so nothing on the NMI in the short time the board came out of reset and fell back into it! so what it appears was happening was the processor ran code and the NMI pulse comes along so it runs its interrupt routine! I can only think this syncs up the watchdog kick or something like that, so without the NMI coming along the CPU runs out of running code and stops thus the watchdog kick in to reset it! so out came Q2 (again)! it is about as far away from the battery you can get!! (well almost anyway you know what I mean) put it on my transistor tester and it said it was 2 diodes! so that means the transistor has lost its gain and is effectively open circuit! now this was fine when I put it back into the board and of course it being so far away from the battery never expected it to go bad! so in went a new ZTX450 (with a good gain reading) and bingo the pulses all returned and it now boots with game software!!!! I cannot now remember what gain the transistor read when I put it back in but it has to have been over 100 as I would have instantly changed it! but have seen this a lot on battery damaged boards usually the transistor is much closer to the battery but the rot changes the transistor gain until it has none! a meter still reads it correct as 2 diodes but it no longer works as a transistor anymore, can be very misleading! Again it shows the importance of running the board for days and weeks after rot repair! lol so the board is NOW running game software on the bench fine and not resetting! surely I have to be nearly there with his one now! Will have to put it in a machine next running the game software!! woooooo hooo! hopefully that will be a good result!!

Thanks Ben... obviously checked that already. I've not found a digital option yet but this is why I'm asking anyone who knows mpu4 😎

Ipac for buttons and hopper (coin out) inputs, and a PacDrive to drive the button lamps (5v) and hopper motors (5V). I use about 8 relays in my small cabinet to do all the triggering, but 2 of them are for a daft note changer I added. As for 10p payouts. Well, you can only run 2 hoppers, so you have to edit the Pacdrive outputs in MFME accordingly. Here is an example of a 10p hopper and a 20p token Hopper, for a game that pays out Tokens, 10p's, 50p's and Pounds You simply use the multiplier column to attain the right denomination.

Underside complete! All Rot gone!

....yup has no effect...