Work continues to try and sort out the continual running motor issue. Everything else works fine and you would have thought it would be easy to track down this fault - the motor only has two wires going to it! Normally the motor is activated by pressing play / FF or RW - this pushed two contacts together and the motor runs as required. For some reason the motor now runs all the time, funnily enough it doesn't effect operation but it is very annoying. Somehow the contacts are being by-passed - a live feed is going to the motor control chip (see photo below). I thought I would go for it and start swapping transistors (and even the main control chip) with the ones in my spares machine. So I went ahead and did this - testing that the motor stopped at each removal. Amazingly the machine still worked after this, but the problem remains! Could it be that the heat from my soldering tweezers corrupted the replacement transistors? Maybe it's something really simple - a bad resistor? I did have it so the motor would stop, but then it wouldn't - almost like a dodgy switch. This is my work station...
I think...that I now have two fully functioning machines. The constant running turned out to be the governor chip - I replaced this with a new one and so far so good - in fact very good with no background noise at all. I might be tempted to replce this chip in other machines...
