Working on bad slave A unit of 20-2168-1 E8 ABA. A master and B have been run with a known good A slave with no problems. Bad slave A prevents motor control in Master and Slave, but PS1 sounds in A okay.
I believe first major problem is that a frame ground is missing on the A slave's circuit board. I believe that the black wire in the tether carries +6VDC from master to slave to power logic on slave circuit board, and that frame ground via the outside rails makes the return path for the +6VDC. Can someone confirm this for me, please!
The yellow wire in the tether is obviously for the slave's electrocoupler (as that's what the yellow wire is attached to in the slave).
Can someone post what signals or voltages are carried in the other two wires, the red wire and the white wire.
The reverse unit circuit board must have had some serious problem in the past, as four repair wires have been added. Can anyone supply a schematic of the circuit board so the I can attempt to see if the repairs were correct.
Removed DC Can Motors from the slave A unit. Of the two motors, one seems stiff, in that at the same voltage from a bench power supply, it runs noticeably slower than its mate. Also, spinning the flywheel by hand of the stiff unit results in about 1 rev, whereas doing the same on the "good" motor results in 2 to 3 revs. Can I use the stiff motor as is? Is there I a way I can attempt to lube the motor? I do not have the tools to take the motor apart.
Thanks in advance!!!
