PS2 Engine revs up and down, no change in throttle, no change in speed

Command or conventional (or both)?

What smph speed(s) or track voltage(s) does it do it?

Conventional, z1000; no meters, so no voltage; occurs just above mid throttle

IIRC a speed change of about 5 mph or so will change the rev sound step.  At mid throttle conventional that can be less than a 1 volt change in track voltage. My speculation is voltage drop from dirty track or going around a curve or grade change is indeed changing the engine speed.

It’s the only PS2 or PS3 engine doing this. However, I’ll run a alcohol rag around the track, and reassess. Thanks for the idea.

Ok track cleaned. No change. 1st video - problem child; 2nd video - another RK PS2 5v GP9. Throttle in same position.

Perfectly normal. That's just a speed notch change, again you are running fastrack, tight curves, in conventional without multiple track feeds and depending  on the track joints to carry power. Basic electricity 101 every connection has resistance and thus losses. As the engine enters the corner and increases load because of drag, you are at the point where even a slight voltage change changes the sound. Ohms law, coupled with an engine in a curve draws more power.

Right there is your single track feed on that loop

Again, normal, expected, and not even an issue.

Vernon - I have a second feed on opposite side, and, this is the only engine that revs up and down like this. It is much worse, much more frequent with 8 RK cars behind it, but, the track noise drowns out the sound. I have pulled out at least 1/2 dozen others ps2/ps3 that don’t do this, and as I said above, it just started out of the blue yesterday. Please rewatch the second video.

@Mark V. Spadaro posted:

Vernon - I have a second feed on opposite side, and, this is the only engine that revs up and down like this. It is much worse, much more frequent with 8 RK cars behind it, but, the track noise drowns out the sound. I have pulled out at least 1/2 dozen others ps2/ps3 that don’t do this, and as I said above, it just started out of the blue yesterday. Please rewatch the second video.

It's a PS2 5V engine. We've spent collectively this forum and everyone who replied more than the 5 minutes this engine deserves.

I'm being honest- what do you think you are going to do?

#1 it runs and hasn't completely blown up

#2 If you did send it in for repair and the answer was a new board it would cost you probably well over $200-$300 for a PS32 upgrade. Pretty sure that exceeds the value of the engine.

Again, it's not a tachometer problem because we do not have a runaway

It's not a reset problem because that's not a feature set a certain way.

It either has a working battery or BCR because you could not run it.

That leaves either the board is failing

or

Just how it responds to your track and voltage situation.

This is almost surely the track voltage variations under load.  I'm not entirely sure why you're so resistant to the idea that this can happen.