problem with engine creeping

I forgot to say, but I'm running with dcs.

Barry

One possible clue, I thought in the steam PS2 upgrade wiring harness system, we have PV generated by 2 diodes on the tether socket PCB. Smoke heater and headlight I believe both use that PV source.

The key there is again, the way that works, there are 2 diodes that use the motor leads (white and yellow) to create PV that is on the purple wire to the smoke unit. Let's say you made a mistake and somehow while servicing the smoke unit, one of the resistors touches the housing that then is mounted to the frame- effectively frame ground AC.

It is highly suspect you may have pinched a wire or moved one of the resistors or some other failure that might inject AC from the frame or shell the smoke unit is mounted to back into the PV line and thus back into the motor. This would be extremely bad and could damage the PS3 board. Again, being you just worked on the smoke unit- that is the first suspect.

Again, you must make sure that no wire going to something like the smoke unit or any light, the couplers, the motor and so on- none of those ever can be shorted to frame.

The only wires that can touch frame are the black power wires in the harness system specifically meant to attach to frame.

You could have the element partially grounding inside the smoke housing.  BUt that usually shows up as short, not causing motor to creep.  To have the engine creep in forward there has to me a small current from the PV (Motor Yellow for forward) leaking to ground via the white wire.

So this also can be a short on the diodes under the PCB that generate +voltage for lights and smoke.

Since disconnecting smoke solves this seems it has to be the smoke PV, but I would reconnect the fan power and see if it still is ok.  If it act odd with fan connected and not heater element, replace smoke fan motor.  G

Here's what I've done so far: I have two of these engines that I upgraded, and they are identical. So, I decided to swap tenders between them, and the problem seems to be isolated to the engine. I have tested both tenders behind both engines, and the problem seems to stay with the engine I had apart. The boards seem to be fine as far as I can tell. I think GGG is on top of the problem. I may substitute another smoke unit first and see what happens.................

Barry

Do you have a volt meter?

Yes, I have a volt/ohm meter. Sorry for the delay in responding, and it will be late this evening before I can come back........I haven't done anything to the engine yet, but I hope to look at it tonight.

Test the terminal on smoke unit to housing. Should be open.  Do a diode check on the engine PCB.  G

is that diagram above the same for ps2 3 volt engines? if not do you have a nice diagram like that you could post?

Same for both upgrade kits.  But not all PS-2 3V are wired that way.  G

@GGG posted:

You could have the element partially grounding inside the smoke housing.  BUt that usually shows up as short, not causing motor to creep.  To have the engine creep in forward there has to me a small current from the PV (Motor Yellow for forward) leaking to ground via the white wire.

So this also can be a short on the diodes under the PCB that generate +voltage for lights and smoke.

Since disconnecting smoke solves this seems it has to be the smoke PV, but I would reconnect the fan power and see if it still is ok.  If it act odd with fan connected and not heater element, replace smoke fan motor.  G

GGG You were exactly right...........I had to much solder on top where I had soldered the new heaters in. The big funnel that sits on top was touching on one side. Luckily it didn't seem to hurt anything, and the engine operates fine. Thanks to everyone that responded to this thread........

Barry