I posted this previously in my thread about the S1 rebuild, but I think I've got a pretty good mapping of all the PS2 components that get connected for a 3V premier steam setup with the 10 pin tether.
This particular engine also uses what's called a MUX setup (I have no idea what it means) but my understanding is that the MUX converts several operating signals for lights and features into a single digital signal so so multiple lights can be controlled using one wire through the tether instead of one wire for each light. At least that's what I understand.
There are a couple of lingering questions I have on this schematic and I've put them directly on the drawing, but I'll copy the main ones here:
- Why do the motor leads go to the MUX receive board in the boiler? Does the MUX convert that power to DC for the lights?
- Is the purple wire that goes from the MUX transmit board to the tether to the MUX receive board the signal carrier? Seems like it, but I also see other schematics marking it as "PV" which might also make sense because I can't find any way the boiler MUX is powered I think. There's just all of a sudden PV available at Pin 1 of the 7-pin MUX connector. So is it the purple wire that brings DC power, or is it rectified from the yellow / white?
- Is there anyone who can map pins 4 through 6 on the 7-pin boiler MUX board to a corresponding input on the tender MUX board?
- In the tender, why are pins 1 & 3 on the 8-pin PS2 connector jumpered? (I've seen them labeled "Mars" and "Ditch" respectively). Are we assuming that the mars and ditch lights will always work together (note there is neither on this particular engine, so I don't know if it's important anyway.)
I've attached a JPG and a PDF if the JPG is not clear enough.
Thanks for your help!