Have an older (i believe) sd45 drgw 5315.The box is all white with red letters saying williams electric trains.There is no horn, bell ect in this engine.The end of the box says no.4525 sd45 drgw5315.The rear motor has what appear to be diodes (3 of them) going from the motor to a blue wire going to the reverse board.Are these diodes factory? or did someone add them for some reason? The engine will only go in reverse.Any and all help and or advice will be greatly appreciated.I can be contact directly at darlenewu@cox.net Thank you.
Sounds like there's a bad reversing board, and someone added the diodes for the voltage drop to get slow speed starts. It's possible, though probably unlikely, it was hard wired it to run in reverse as the 2nd loco in a two unit lash up.
Len
A lot of older Williams engines had just two motors installed in them, no horn or bell. If you want a more powerful set of motors, buy the new upgrade kit from Bachmann/Williams. Also Bachmann sells a replacement reversing board, look in the parts section.
Lee F.