Just been having a play with an idea to make the MPU3 'clubbers' a bit more exciting. Here I've done a couple of ROM hacks to make the reel spins much faster, and also the 'skill stops' (I'm sure they are actually fixed predetermined stops lol) much faster.
At around 0:50 in the video, I have a gamble, and you can see it going up on the alpha display, when I hit Double... until I get to £4.80. At that point the gamble sequence continues, but I no longer have the flashing start button to continue gambling, so I have to collect some of the win.
Is this the infamous 'Gamble block' people have mentioned to me before? Apparently there were these blocks to stop you gambling up to say £100... but also in early ROMs that are not dumped, these blocks didn't exist, and were only introduced later.
So yeah, is this definitely the 'gamble block'? I may try to figure out how to remove it if so...