I've spent a few hours on the Sega G-Loc over the last few days. Given the state of the machine, there was a lot of corrosion and damaged wires from rats. I spent a fair amount of time repairing the wiring harness and addressing obvious areas of corrosion on terminals, but I suspected that there were still issues - specifically corroded terminal pins causing connection issues between the various PCBs that are in the machine.
I was able to track down another full wiring loom from a G-Loc machine in the US so I bought it and went about the process of replacing the entire wiring loom. In the process of replacing the wiring loom, I found a few chewed wires that I hadn't spotted previously. Once the entire wiring loom was replaced, I managed to get the boundary detection system working.
The boundary detection system is made of of three pairs, of senders and detectors. A sender has two wires, a +12V DC input and a Ground wire. The detector has three wires, +12V DC, Ground and "Sense" - the sense wire is referred to as "out" on the actual sensor.
The other part of the boundary detection system is the "Motion Stop" buttom.
The motion stop button has five terminals labelled as NC, NO, C, L and L(+). More on this later..
With regard to the sensors, all three pairs are 'summed' into one hub. In other words, each pair of sensors comes back to a hub and all lead into a common output of 12V, Ground and Sense which goes to the digital motor control board. Under normal circumstances, the sense wire is 0V DC. But when you block any pair of boundary sensors the sense wire goes to +5DC until the blockage is removed.
Now comes my dilemma...
When I plug the motion stop button back in using the following approach...
...then when the button is depressed, the "sense" wire goes to -5V DC. The "sense wire" is the Grey and Yellow. +12V is Red and Ground is Red and White. So my dilemma is that surely pressing the motion stop button should do the same thing as when the sensors are block - that is surely it should go to +5V DC, not -5V DC?
It would be super if someone who owns this machine could confirm the wiring to the motion stop button. Pretty please!
Although I haven't entirely figured this out, the good news is that the boundary sensors now work! When the receivers are blocked, a red LED lights up on the relevant receiver. I also found some other chewed wires too during the process. One step closer to getting the machine to work.
The next challenge is that one of the rebuilt motor control boards keeps on blowing the R1 and R2 resistors.
R1 and R2 are cement, wire wound 1.2 Ohm, 5W resistors. These boards can be set to either take 100V AC or 200V AC as their input. My test rig only has 100V AC, while the cab has 220V (Mains) AC feeding these boards. From what I can tell, R1 (or) R2 does not fail when used at 100V, but seems to fail when using the 220V AC input.
TR1 is usually a M8GZ47 but I have replaced it with a BT138X-600E in both the boards. TR1 was my first suspect, but I'm not sure. TR1 is the same in both boards now, except only R1 and R2 in this one seems to fail and only at 220V input, not 100V input. I am really keen to hear some other opinions from folks who are more expert than I am.
I've labelled R1 and R2 in the image below. The board on the left is the one that seems to fail. I haven't pulled R1 and R2 yet to see if one or both of them have failed. I just find it odd that they seem to fail at 220V versus 100V. As you can seem I have replaced these before. I am wondering if the voltage rating of the replacements is not up to spec, despite the fact that they are all labelled as 5W. Keen for thoughts on this one.