Original MCU with either PCC will work perfectly on the SMC2 except for one little thing. The mech should pick up a record going left to right. It did it once. What did I do to get this of a sudden working? New day? I have an intermittant wire problem somewhere. The worst problem to have. I will get it fixed. The Gen2 works except it goes too far left at times, past the limit switch ramp, and just stops. If I try to move it manually right it pulls back left. I have to turn the box off and move the mech manually back to the right about 5 spots then turn the box back on for the mech to reverse. It would seem as if the MCU wasn’t reading the limit switch. If I use the service switch to scan from left to right I can manually hit the 100/200 limit switch and cause it to reverse. I found two switches in the vertical stack on the mechanism that have to do with the mechanism reversing. Never knew their purpose and was briefly hopeful. Cleaned and made sure they were adjusted properly. The hope died shortly.

Ron Rich advocates setting the limit switches up a little differently in that the right side carry over switch should be open always. This makes the mech, after the last record, go three detent pulses and stop. This is making the mech do a complete reset count after a new selection is then made. I’m not a fan of this. I reset the limits acording to factory. I’ve had many SMCs and have always set the limit switches like this with no issues. They are now set, have been ohmmed and wire leads resoldered. They are golden. The problem is elsewhere.

I benchtested the HFMA2 amplifier on the bench. My one bright spot for the day. It is awesome. Lot’s of volume and plenty of tone when bass or treble are adjusted.

I cannot get a reading from the Gen2 MCU for its detent to limit switch test.It comes with this plus a neat detent on/off pulse width test. I adjusted the detents until I am getting roughly 25ms on/off. This seems to have no effect on selection. I sat down, again, with schematic and my trusty Fluke meter and started tracing out the detent and limit switch circuits. They check good on the mech so I started checking continuity through the mechanism cable to the PCC where it goes to plug J3108. Pins 5 and 10 are basically a loop through the mech limit and detents and back to the PCC.The MCU depends on these two wires to count ( the count consisting of on/off pulses) and thus tell it where the mechanism is. I pulled those pins and soldered the crimp to the wire in case of a loose crimp. I did the same for pin 1-ground, pin 3 12v, and pin 4 the clock generator. I will look into this clock generator more later. How did I get good at Seeburgs? Doing stuff like this for 30 years. Comes a problem, no one to turn it over to so I fix it or junk it. I’ll choose fix please.