I've got a Mata Hari machine I've had for about 10 years now. Do all work myself. However i'm looking for confirmation on a current problem. The knocker relay locks up only during play. During the start of the machine if I go through the relay checks it's fine or if I test it on the relay board off the 24volt line fine again also. Only during play does it lock up and draw power constantly causing me to quickly turn the machine off. I took the relay down and checked it as far as the knocker pin goes and everything moves freely. So I'm asking for opinions on the problem. Thanks

Thanks. I've a friend who owns a few machines that thought this also so it looks like I'll try that first. Not an expensive try anyway.

So which transistor on the board would be for the knocker relay? Most of my work on the machine has been fairly easy stuff. And what does BigAl56 mean by "bad chip socket on the mpu"