Proto 2000 SD7/9 Pickups

The SD7/9 locos from Proto 2000 are smooth running, quiet locos. However after a few hours running they can get erratic due to the pickup design.  Below is the proceedure I use to combat this. My locos have decoders for DCC and they are programmed for a top speed of 35 mph and do a lot of low speed switching.

Click on any image to enlarge.

Remove the trucks from the loco and then remove the side frames. The photo shows how the contact bar sits on the axle extensions. The wires to the decoder are just spring clips.

With the side contact bar removed  we can add extra pressure pickups tothe axle extensions. I use 12 thou (0.012") brass wire, why thissize?  - Because I have plenty - I use it for hand rails and otherdetail parts. 10 thou brass or phozor bronze would be just as good. Thewire will wear out after about 10 years of very heavy use, but is stillworth the effort.

Clean the area to be soldered with a small file and then tin the surface(Tinning - heat the surface and apply a small amount of solder, theflux in the solder will clean any oxidents from the area). Also tin 3mm(1/8th inch) at the end of the brass wire, this will endsure a goodbond to the contact bar. Solder to the bar as shown and bend downwardacross the axle hole and cut to length as shown.

Solder the flexiblewire, that connects back to the decoder, to the same location as one ofthe wires. I always have plenty of wire left from decoder installs -they always supply a good length. Refit the side frames making surethat the wire sits on top of the axle as shown. My locos have sounddecoders fitted and soon show up any pickup problems. I did thismodification to the SD9 and then ran it at low speed all over my systemfor an hour without a glitch.