Can you provide a reference or instructions on how to open the tender in order to install a sound decoder.
Thanks.
To the left, go to product reference, diagrams, spectrum and you'll find the J listed. Download and open the file to see the tender and its parts. That should give you an idea where the screws are
If the 611 tender is like most of the other Spectrum tenders, there will be one screw directly behind the front truck and two tabs in the rear of the tender behind the rear truck. Unscrew the screw, lift the shell up and forward.
If it is like the 2-8-4 tender, there are four screws, one in each corner, deep set in a hole so you can't see the screwheads.
In any case, don't remove the truck screws.
If it's not like either, I have no idea.
Gene