I have an early Proto (shell off chassis) blue box GP9. Someone has stripped out the light board and am left w/ only wire leads. The red wire obviously runs to the (hopefully isolated) lower motor brush, the top brush clip only shows where wire was unsoldered, Now the truck leads, these are done like old BB Athearn, the truck clip for one rail has both wires soldered together. But where do these units PU power from the other rail. If the motor is isolated the entire chassis shoud do this. There seems to be no factory provision where this was done. Since this was rather butchered in some attempt to add a decoder should I treat it as normally hardwiring an old BB and add screw to the frame for this.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Is it a Proto (Lifelike->Walthers) or is it a Blue Box (Athearn?) The older Athearns used the metal frame as one side of the circuit, so there are no wires on that side. The power goes from the wheels to the trucks on one side, and then right to the frame through the metal pin that holds the trucks. The motor is mounted directly on the frame, and needs to be isolated before you can add a decoder. The other side of the truck is isolated, and a wire takes that power to the other side of the motor.
If you keep the frame as part of the circuit, be sure to isolate the couplers with a Kadee draft gear box or some other plastic mounting system.
It takes an iron man to play with a toy iron horse.
I believe he's talkign about an early Proto release, which is pretty much identical to the Athearn Blue Box except they used a piece of wire to connect the truck clips instead of the metal bar. So the same caveats apply with regards to isolating the lower motor brush, since the frame is hot.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks for the help so far. This is a very early Proto, w/o having the light board or even knowing if this came DCC ready, I'll have to remove the weight and posssibly the motor to check if it is isolated. I nevr ran into this w/ any other P2Ks and I have installed decoders in well over a dozen, Did the early FAs, GP18 real BB clone have the hot frame? Thought the GP9s were a bit later runs. have early SD7s (plug in board), and GP9s about 2nd run and these (decoder replaces board) as well as all the newer versions.
The red wire coming up from the lower motor brush does look to be separate from the frame. Won't know until pulling weights and possibly motor to check.
Here is how I did mine.
Orange goes to the bottom motor wire. Gray to the top of the motor. (Had the motor leads backwards the first time around.) Red to the weight/frame assembly. Black to the tabs on the trucks. Lighting is your choice. I used LEDs.
Unit on left is a P2K GP30 with 14v bulb.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
Thanks, I'll just approach it as a hardwired BB. Really didn't want to run this at first, was just keeping it for spare parts. I've never run it, but I bet it has cracked gears also or will soon.
A shame such a decent engine was so butched up, even the weight is cut (? speaker?) -
If it doesn't look liek Mike's, then yeah, someone hacked it up. If the frame was cut then it probably was an attempt to install sound. Don't let the cracked gears bug you, you can order Athearn part 60024, SD40 gears, and they will fit right in. Cheapest alternative since you aren't the original owner and probably have no sales receipt to get warranty replacements from Walthers. As long as the body shell wasn;t hacked up too, you should have a nice looking and nice runnign piece. I love my PK locos, they look nice and pull great, and ar quite reliable ocne the original axle gears are replaced. Long stints pulling a heavy train on the club modular layout without a hitch bear this out.
Some of the early Proto units utilized a ground lug to the chassis . One rail picked up through the truck straps as you have noted, and the other rail is grounded to the chassis like the old Athearns. The motor is isolated from the chassis, you just have to add that ground lug somewhere to the chassis ground to pick up the other rail.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
rrinker If it doesn't look liek Mike's, then yeah, someone hacked it up.
Not necessarily. I had some older, "pre-DCC-ready" P2K GP's that didn't have a PCB, and no recess in the top of the weight to accommodate one. So they didn't look like Mike's, but they weren't hacked up, either.
rrinkerIf the frame was cut then it probably was an attempt to install sound.
I do agree with you on that point!
It does appear that the cutting of the frame may have been an attempt to add sound. The motor turned out to be isolated, thus the wire up from the bottom brush. I just hardwired to run on DC just to make sure before installing a decoder. The gears, all 4 infact,were cracked, just stripped some out of old Athearn BB trucks and it runs like a champ. The shell is perfect, really surprised since the chassis was so hacked. The extra detail package was never even opened. I doubt this has any running time at all the wheels show no wear.
Thanks guys for all the help.