30-1188-1 challenger ps2 upgraded

Btw...this WAS ps2 5 volt...upgraded to ps3...

First things first, check very closely for ANY mechanical binding or resistance.  The smoke affecting things sounds like a problem with power, so maybe there's a high resistance connection in the works.

Should this thing creep away under normal circumstances?

I've heard MTH spec really doesn't guarantee smooth running below a certain minimum speed...which I have no idea how you would measure. 

My factory ps3 engines will in fact creep...my lion masters do the creep really well...

This one, for some reason...not so much...

This engine has mux boards...could that be an issue? The tender mux was bad, as well as the ps2 board was dead. These were replaced...

The engine mux was good according to my tech...

I'm running a tui with an mth 1000 series brick transformer for power.

Apples to oranges but I have a Premier GS4 Northern that is a PS1 to PS2 3V conversion. It will creep along at 2 smph smooth as silk. It does have a large Pittman motor, which probably helps. 

Was any other work performed on the engine like traction tire replacement? If so, check to see if the eccentric cranks were positioned correctly. You may have some moderate binding going on. When the main drive rod is in its lowest position, the eccentric should lean forward as pictured.

This is a dual motor unit and it may be possible that one motor is not doing so well. I have an MTH railking F3 with dual motors that behaves the same way. I removed the shell and pulled the motor without the tach tape but left it hooked up to power. At 2 smph the tach motor ran smooth and the other one didn't run at all. It wasn't until about 6 smph that the second motor started to turn.

Ultimately, I had a bad motor.

I could get right behind that one...

I saw it run on a test stand...the first thing I noticed was the rear motor came on...then the front one.

My tech told me that the only motor being 'controlled' was the rear motor...the front motor then ran independently on the same relative voltage. 

Because of manufacturing tolerances the motors had variation in what voltage was required to make them run...but that the startup speed was within the spec MTH would guarantee for smooth running...which I believe he said was 7 smph or above. 

It does that more or less...but getting it up to that without jerking is a 'challenger'...lol.

Once it's up to speed, run a great. Just has a starting problem. 

This was already PS-2 5V, so the PS-32 (I assume) should have it right back to how it ran before.  John, hit something on the smoke, not sure why that is causing issues.  It does draw current, and if operating conventional with lower voltage you will see additional voltage drop and motors will try to slow.  But in DCS with full voltage, the speed control will kick in.

Custom sound, what does that mean? That can be the issue too. 

While both motors may or may not start together in a cradle, if coupled via track they should be fine. Unless one is really bad, but that would have showed up before the PS-2 5V board died.  Tech needs to get it right.   G

I've actually never had a dual motored unit on the rollers that has both motors start and run together at low speeds, this is perfectly normal.  My test for bad motors is to test individually with a DC bench supply to see what the current draw at various voltages is.

The custom sound is a selected group of mth spec sounds for a challenger that the tech had  assembled from a couple different programs(?) and loaded onto a g scale challenger...which had quillable capability as well.

Great horn and chuff sounds...much better than stock ps3.

I asked if he could load that on my engine and he said yes...but because of driver sizes, gear ratios, etc it would have to be tweaked to get it to line chuff, puff, and driver rotation up.

He said, and I haven't checked, that I guess there was enough difference that in order to get 4 cuffs per revolution the control had to be set for 3...

Once since I've run it it started up running with the watercock open sound...which is correct when first starting up with wet cylinders...my stock ones do this...but generally it jumps...so I just crank it up past the jump until it runs smooth...which is kinda disappointing. 

It wasn't until I was given a heads-up by a third party that I even knew there was an issue with this repair.  I just exchanged texts with Mark and he is going to bring the engine back by.  The folks here didn't do the repair and don't have the detail history which is critical for understanding what is going on.  

The jerking as you are describing is clearly not normal and sounds like the other control components need to be replaced.  The PS2 5v board was dead but also found (oddly) the Tender Mux board was also bad.  I identified and corrected an issue where there was evidence/risk of shorting of engine circuits to the engine to the boiler/frame.  And while it was not 100% clear at the time any shorting had actually occurred, based on what I am hearing now I think it did and that it actually affected the remaining electronics.  Other repairs/issues were also found with engine connections and were corrected.  Engine was test ran for 2 hours (1 hr in each direction).  

Regarding the minimum speeds, I indicated that some O gauge engines (particularly diesels) may not run perfectly smooth at 1 or 2 maybe 3 mph.  (I definitely did not indicate 7mph).   Also note that when running on test rollers, sometimes there is a little bit more resistance depending on how truck/engine set is positioned that can cause extra drag on one engine set/truck.  The difference we saw on the test rollers is one that would load balance out and should still run smooth and I'm certain is different/separate/unrelated to the jerking.   

At any rate, based on all outward appearances it seemed like it was just a normal PS2 5v board failing but there was the suspicious issue with the failed tender Mux.  In the end it looks like there may have been more going on in this case than just a failed PS2 5v board.  All root causes that would have caused Mux damage have been repaired so we just need to reconfirm and replace remaining items and this should resolve the problem.

Raymond

Raymond,

Thanks for chiming in, those were some pretty big pieces of the puzzle! I believe this engine is in good hands and you'll get to the bottom of it. Whatever it you find out with it, a final repair update would be great. It's always nice to learn some new troubleshooting & diagnostics information for future repairs.

Sorry to anyone offended...I was telling ray this is kind of like having a modified car...I have no basis for what to expect on something like this that has been changed from factory. My experience with modified cars is that it's never again factory and at some point you have to accept the difference to have what you want.

Btw...I love the sound set he put in it and was at first reluctant to take it back for fear of losing it...which is why I was asking if that would be an issue. I don't have any understanding of how the motor drivers work or how the entire system interacts with regard to power supply across all the different functions...just watching it run is an indicator but I'm sure it's way deeper than i imagine. 

I don't think 99% of the failures of the tender or locomotive mux would cause motion issues, those don't go through the mux.

With the bad Tender Mux in place the engine no speed control whatsoever. 

I will get it sorted out.  Thanks.

Got it sorted out.   The bad tender mux actually damaged the new PS3 board which has now been repaired.  The variance in performance during testing was very slight when tested here so it wasn't obvious and only jerked very infrequently (at least under my testing conditions).   Have fun Mark and thanks for all the replies here trying to help him sort it out.  

Props go out to rayman for being patient...when we finally got the engine to replicate the problem (took a few tries) he went right to it...and then when I watched him fix the damage...all I can say is I am impressed with his ability...good work!

A true example of a great repair tech...you can trust his work...and will go the extra to make it right.

AAA recommended!

Interesting, of the thousands of repairs the only bad Tender MUX I have seen was when it got crushed when owner installed shell on the tight tender of the older Atlantic PS-2 5V.

John, The Mux Tender does have the 5V, and PCB ground go to it. So if some how the tender mux shorts it will effect the board 5V buss. Same affect as a smoke fan motor going bad.  Either by noise or high current draw.  Mux issues are extremely rare though.  Engine mux more susceptible to damage because it is the PV source and actually control light loads and in some cases 5V loads of tach. G

In this case it is hard to know the prior history as I believe this was an ebay engine.  (I'm sure this is another case of ebay seller unloading their problem on someone else.)  The tender mux was properly seated and wasn't at risk of shorting in tender.  Unless the ebay seller shorted with tender shell as noted, I don't think that applies here but can't know for sure.  

To me it is not about history of engine, but if a component that normally does not fail can take out the PS-32 board I would like to understand how and why.  Did it kill the Stacker board?  The Tender mux is a simple multiplexer that takes the interior and HL signal and sends it out a single line.  Shorted wires to chassis I understand, just never seen this board damage a 3V or 5V board, but....never say never.  Just trying to understand it.  But I guess really can't know.  G