pcu1 to peco points wiring please help

I've dug out the instructions for a Seep motor (bought one to try and stayed with Peco)
According to that, the diagram I am using is wrong (thought it a funny way to wire up but they make & sell it)

The common should be negative so the diodes are the wrong way round.

Using one motor change the diodes round and try it - if it works
Connect up the next motor to Group 2 and try that

will stay on line till we come to a conclusion

Chris

Hi denver

DISREGARD MY POST #9

I have spoken to the electronics man (Greg) at Gaugemaster today to confirm the diagram is correct and how the PCU1 is wired internally.

The COMMON TERMINALS C1 C2 C3 ARE POSITIVE and are fed from the rotary switch.
The PCU1 centre-off switches then provide the path back to NEGATIVE to make the circuit.

The diodes as shown in the diagram are the correct way round (silver ring on the end is furthest from the point motor).

On the PECO point motor the terminals on one side should be joined together and wired to the relevant C1 C2 or C3 - that I believe is what you have done.
They recommend that you solder a diode DIRECTLY to each of the terminals on the other side of the motor so that the silver ring is furthest from the motor (you can shorten the lead to suit), then solder wires onto the free ends of the diodes and connect one to the A terminal the other wire to the B terminal on the PCU1. Again you can shorten the diode lead but use a piece of insulation tape over each joint to prevent shorts etc. - heatshrink would be better but if necessary you could fit it afterwards when you know it works, a quick touch with the soldering iron will make it shrink.

The soldering of the diode directly to the motor is to try and eliminate errors and it is easier to bring up to 6 wires together for connection at the A and B terminals rather than the ends of 6 diodes. The diagram needs expanding to show this more clearly.

I drew out the circuit and without the diodes there is a problem with the current getting into the wrong coils and so operating, this has nothing to do with Back EMF as mentioned in some other places and it can be safely ignored in this application. The important thing is that regardless of the Common used each point motor must have its own diodes arranged as shown and the wires taken back to the A and B terminals.

The common mistake is fitting a pair of diodes to the A and B terminals then connecting the wires from the motors onto the free ends, that allows the current to flow around the other motors and fires them regardless of their group on the C terminals.

For your interest and information if you were using a standalone Gaugemaster CDU the supplied diagram shows the common wiring as negative and the centre off switches are on the positive side - these PCU1 are backwards when compared to the standalone. Maybe it should be called a feed rather than a common.

Let me know how it goes

Chris