Tmcc diesel wiring schemstic

Rod Stewart published the pinouts for about a dozen TMCC and early Legacy boards here.  While your board is not listed, the 691-PCB1-11E Rev A board he listed appears to have a similar if not identical layout.  It should give you a starting point in tracing the wires to the various switches.  Also check the back of the board to see if the pinouts have labels.  While this may also be helpful, some forum members have pointed out that they are occasionally wrong.

Besides the Run/Program and RS/SS switches, other switches used by Lionel are Smoke, Odyssey, and Lamp (marker lights?).  The 6th one escapes me.

Bob

There typically aren't more than three or four stock switches for a TMCC setup, switches to bypass the logic and go directly to the motor are most certainly not stock!

The 691-PCB1-0B1 is a somewhat special case, it has logic onboard, a VCO for the diesel ramping at least.  I recommend you spend a little time with a meter to determine what connects where.  I've attached the TMCC and RS4 board pinout document to this post to aid in that endeavor.

@NYCBuffalo posted:

I have a 691-pcb1-0b1 board set and wiring I want to put in my lionel convention sd60. Most of the main wires were labeled and the boards work fine. There’s no less than 6 toggle switches and 2 little full wave bridge rectifiers in the wiring and I can’t figure out what those do. I did trace the run/prog switch and rs/ss switch successfully. The others look like ac polarity related but not sure. I have space for 3 total in the chassis already. I figured run/prog, smoke and ? For the 3rd. Hoping I can bypass the others.

It looks like 3 switches would allow operation  on dc track power right to the motors bypassing the board completely. Is this a real thing?

It might be helpful to know what this rats nest came out of. Do you have an catalog number at all?

Rod

@Rod Stewart posted:

It might be helpful to know what this rats nest came out of. Do you have an catalog number at all?

This has to be someone's mods, Lionel has never made anything that has switches to bypass the electronics and run directly on DC.  They had cheap DC powered locomotives, but nothing with TMCC like this.

It's often possible to match an engine's wiring up to one of the common TMCC schematics published by Lionel in their service supplements up to about 2003.

The extra switches and bridge rectifiers seems like someone tried to convert it to DC operation maybe. If that's the case you should be able to do away with most of that extra clutter.

Sorry grj; missed your post.