Couplers uncouple while train is moving without sending a signal

I had this same problem on an early TMCC conversion. As I recall, Jon Z. had the answer(s). Going by memory, first was to move the connection to Ground for the coupler from its shank and back back up to the TMCC board, the second was placing a non-polarized capacitor, but I cannot recall. I will have to dig up the manual for the conversion. One was a 2343 horizontal motor F3, the other was something like a 623?? C&O switcher with coil couplers. Still have the 2343, but as I recall I changed it from an LCRU to an Electric RR product.

Thanks for your reply I appreciate it.  I am not actually making any conversion   Just started opening on their own  Not the other TMCC engines

First step, determine if it's mechanical or electrical.  Unplug the coupler connection from the motherboard and run, see if the couplers still open.  If they still open, it's mechanical, if that "fixes" it, it's electrical.

For electrical issues, install a 1uf 50V non-polarized capacitor across the coupler output, I like to put them under the motherboard across the connector.

For mechanical issues, probably just replace the coupler.

sure it is electical since both couplers open on own on both locos.   I would have no Idea how or where to get the capcitor you speak of

Couplers popping open can be mechanical as well.  Are they opening when running or just sitting on the tracks?

Sorry so much later posted.   While running only

Well, that can clearly be either mechanical or electrical.  No sense in trying to fix it until you identify which problem you have to fix!

Thanks for your help

any advice on how you take a truck off at 577 nickel Back rd tmcc diesel?   Thanks

The product number would be a big help.

Yes thanks.  I figured it out.   Not always able to get a product number.   New to this!  Thanks