MTH 11-6056-1 #261 steamer speed problem in DCS, PS3 - Problem Solved!

What's the spacing between the tach reader and flywheel? If it's too far from the flywheel the tach reader won't pick up the stripes and the locomotive will take off at full throttle. Also double check the tach reader wiring to make sure that there are no pinched wires. If the boards behave correctly on the test fixture it's either a tach reader spacing issue or a wiring harness issue.   

spacing is good.  I will check out the three wires tomorrow where they connect to the tender board all the way to the tach reader.  Probably have one that shows no continuity.

I'd also bet your spacing is too wide. Put the reader closer to the flywheel. Some boards need a tighter spacing for some reason. I have repaired several G scale engines that run too fast. I now have another doing it after years of running fine. Some came running fast right from the factory.

You can verify the reader is working at all, by placing a card in front of the reader and block it while running. If it's chuffing, it's at least working, somewhat.

These RTR ps3 boards are totally different from other boards.  There are regular boards and there are EMI compliant boards.  You can not tell the difference by looking at the tender boards, but on the engine board the EMI board is slightly longer than the regular board.  Both these boards are EMI boards.  These boards are new, there is no chuffing because he software has not been loaded.  Now those boards will not run DCS on the Test Assembly.  They run conventional only.  From what I understand you do not want to mix the boards (one EMI - one regular). 

There is no parts list under the 11-6056-1 'support'.  Finding a new harness will be difficult.  Now I don't think I can get them back to the DCS mode, probably blew the DCS relay.  Can anyone service these tender boards?

checked all wires from engine drawbar-to-connecter on boiler board, no shorts or broken wires.  Checked the three wires going from the boiler board to the tach reader - all show continuity.  An unusual reading when checking those three wires with a non-emi boiler board connected, the grey wire checked good.  The orange wire checked good.  BUT - the blue wire showed some continuity with the grey wire.  Like there is a short in the non-emi boiler board somewhere.  When the connector is attached to the EMI boiler board, all three wires check good continuity, no shorts or anything.

I even tried a different DCS remote, same thing.  Runs very fast in DCS.  Placed a paper stock between the tach reader sensor and the flywheel - no difference in performance.  At that speed there is no chuffing sounds.  Also installed the engine shell to block any stray light - no difference.

To do this with two different, and the second tach reader known good, is strange.

Try and get the tender boards - you will have to wait about 6 months.

@bruce benzie posted:

These RTR ps3 boards are totally different from other boards.  There are regular boards and there are EMI compliant boards.  You can not tell the difference by looking at the tender boards,

Actually, the EMI tender board has an extra choke under the bridge rectifier right near the DCC/DCS jumper.  It's a square ferrite block about 1/4" square.  The non-EMI board will have an empty space there.

Saw the choke.  It is square, black and surface mounted.  There is no DCS/DCC switch.  Does anyone work on these boards?  or are they a total loss when something goes south.  Why they developed these I can not understand.  They are never in stock.  MTH  already had a nice ps3 steam board, why another one?

Guess I will have to let this engine go running conventional only.  Too expensive to repair when compared to the purchase price of the RTR set.

Bruce

No switch, but there's a jumper pad right next to that choke with a jumper cap on it to configure for DCS.  If the jumper isn't on those pins, you're in DCC mode.

There's not a ton of stuff you can do to these, but there are some replaceable parts.  There's a couple of common mode chokes that seem to be sacrificial and can kill the board, those I've replaced a couple of times.

If it works on the test set the boards are fine and the engine is the issue.  Did wires go back on new tach reader correctly?  G

George,

Yes, the tach reader wires go back to the connector, each of the three wires checked for continuity ok and the wires are seated on the male connector pins.  Also checked the pins on the connector prior to inserting the connector to insure they are all straight up and not tilted.  Will try again on the test assembly, then install in the engine and check again.

Bruce

@bruce benzie posted:

..

Runs very fast in DCS.  Placed a paper stock between the tach reader sensor and the flywheel - no difference in performance.  At that speed there is no chuffing sounds. 

Stan,

Our service manual page 11-24 specifically states that these boards do not have sounds in conventional.  

Something, and I think it is a relay,  is preventing the boards from getting to DCS.  If I apply 18VAC in the DCS mode, connected to the TIU,  the engine goes directly to conventional.  Being PS3, there is no audible 'watchdog' signal to listen for.  Something is causing it to not go into DCS.

Bruce, what service manual is that?  I've never heard of any PS/3 that doesn't have sound in conventional.

@bruce benzie posted:

..

Something, and I think it is a relay,  is preventing the boards from getting to DCS.  If I apply 18VAC in the DCS mode, connected to the TIU,  the engine goes directly to conventional.  Being PS3, there is no audible 'watchdog' signal to listen for.  Something is causing it to not go into DCS.

Now I'm really confused!  I thought the engine engine was taking off when the DCS remote commanded 1 sMPH or whatever minimum speed step.  Now you're saying the engine always reverts to conventional?   Or is this a change in behavior as a result of tinkering...

@bruce benzie posted:

...

Start up in DCS.  engine starts fine, no abnormal current and sounds come up ok, horn and bell work.  Advance speed on the DCS remote and it takes off and runs fast.  Tried again, same thing.  Installed a new tach and it does the same.  Performed a factory reset, same result.

John - chapter 11, page 24,  2017 edition has the matrix for these boards.  Yes, it originally worked in DCS on the test assembly, but later failed in the DCS mode.

I guess my old 2013 edition doesn't have those pages.  Since MTH hasn't seen fit to publish the manual on the website so we can update our documentation, I have to live with what they originally gave me.

In any case, I maintain that I've never heard of or seen a PS/3 board that doesn't have sound in conventional.

Back in the day PS-2 boards where shipped with no sounds set.  Just test tone.  PS-3 are shipped with the testall flash code and sounds normally.  Either way go reload flash and sounds you want.  Try again.  I answered your e-mail, you need to refresh yourself on the PS-3 boards.  PS-3 steam have a jumper pin set for DCS/DCC.  Either switch or jumper plug installed.  This is the same way PS-32 boards come in the Steam upgrade kit.  Jumper on the pins for DCS.

PS-3 Diesel (pure) not PS-32.  Have the 40 pin plug doing the control via wire 1 and 40.....to a switch, or tied together with wire nut.  PS-3 steam does not use 30 pin connector for this.

SO NORMALLY, you take the tender board out of engine, put a jumper on the pins so your in DCS mode, and use your test set to load files, test in DCS.  Once back in engine you need to reinstall the switch plug for the DCS/DCC or leave the plug on if the engine is RK with no switch. 

As far as speed control, has to be engine.  If you tested boiler and tender board with bench tester and it worked.  So maybe boiler board is bad if you did not test it.  But it would not be the first time I have had a bad (new) tach reader either.  EMI versus non emi has nothing to do with this.  If you mess that combo up you have a shorted motor function when in a direction and engine shouldn't move.  G

Problem solved!  The TIU (fixed 1) on my test bench has a problem.  Ran fine on the layout in DCS.  Thanks to everyone.

Bruce

Wow. just wow.