K-Line Big Boy no reverse

I'd take the motors out and then try powering it in reverse and see if they move now that they are not connected to the wheels.  If they do they you have a binding issue.  If they don't, then you have a motor drive board problem.

@jaketrainz posted:

While I’m in the middle of another repair (https://ogrforum.com/...ke-unit-parts-screws) I have discovered that my K-Line Big Boy will no longer go in reverse simply out of nowhere. Only started happening a few days ago. The engine will go forward, neutral, neutral, neutral, forward and so on with no reverse. I should also mention this is the TMCC version and I am currently running conventionally. I have the smoke unit switch off since the smoke unit is under repair currently and out of the engine. I swapped an R2LC from another engine I have and the behavior stayed the same so I’m assuming it’s likely not that. I also checked all the connectors to the boards both on the motor driver board and the board the R2LC sits on (not sure what that’s called). I have the run/prog switch set to run and tried it in prog too. I don’t hear any buzzing from the motors when it’s supposed to be in reverse. Anyone know what might be causing this?

There are two things you need to check.

1) There is a four-pin wire harness (white connectors on both ends) that runs between your locomotive motherboard and the DCDR motor driver board. Make sure all four wires are firmly attached to their connectors at both ends.

2) If the above doesn't change anything, and you've already tried replacing the R2LC, then you've likely knocked out one pair of the drivers on your motor driver board. Time for a replacement DCDR.

TRW

If it's not the cruise version, it uses a plain DCDR.  Drop me a line, I'll send you a replacement for the cost of shipping, I have a bunch of them.  If it is K-Line Cruise, then you'll either have to try fixing it or replace it with the ERR Cruise Commander M module.

@gunrunnerjohn posted:

If it's not the cruise version, it uses a plain DCDR.  Drop me a line, I'll send you a replacement for the cost of shipping, I have a bunch of them.  If it is K-Line Cruise, then you'll either have to try fixing it or replace it with the ERR Cruise Commander M module.

I think it might be cruise but I’m not 100% sure. Below is a photo of the board. Would you be able to tell me if it is or isn’t? The part number of the board 691-DCDR-C MDK Rev. C

Plain old DCDR, send me an email to my profile address and we'll fix you up with a replacement.