MEP-802a output contactor

[rhurey]

Got a new (to me) MEP-802a that looks like it was in mid-rebuild and they threw in the towel, but I'm making progress and now need some advice on the output contactor (K1).

Some background:

• Picked it up with 75% of the panels having a couple of screws holding them down.
• Looks like a new (2010 rebuilt) motor.
• Had a destroyed starter solenoid, looks like someone screwdriver jumpered the wrong two terminals to test it. (replaced)
• The K2 relay is intermittent in working, and the K18 relay had all it's wires loosely attached.
• The P6 harness looks brand new.
• Found all the small wires on K1 were installed in the wrong locations. (X,Y,11,12)
• When powered on, K1 was always engaged with no way to shut it off.

Traced the X,Y,11,12 wires running to K1 and got them in what I think is the right places. (There's no label on the K1 I have, but if the terminals are in the same place as on on ebay...)

So now K1 will close if I move S5 to Closed, but when I release the switch it opens again. So I'm sure if it's K1 or S5 that's not working correctly.

Any thoughts?

 

[kloppk]

With the set OFF...
For starters I'd suggest checking for continuity from K1-12 to Ground.
Then from K1-11 to K8-12.
Then from K1-11 to K8-11
Then From K1-11 to K8-8
Then From K1-11 to K8-7
Then From K1-11 to S5-3
Then From K1-11 to S5-2

Then check that CR3 the end with the white strip is connected to from S5-2. (Diode CR3 is wire across S5 terminals 2 & 5)
Then check that the other end of CR3 is connected to from S5-5.

Then for continuity from S5-5 to K1-Y

If all continuity checks good then test diode CR3

 

[rhurey]

Oh ha....

I'd traced all the wires from K1, but hadn't done the continuity tests...

Turns out one end of 100U wasn't stripped before it was crimped.

Yet another reminder to double check everything. Especially stuff that looks "new"

 

[Guyfang]

The ground wire, for the holding circuit. Any wire with a wire number, with a 100 in it, is a ground wire.