Current Train Problems

Nicholas,

 

Your engine is working exactly as it should.

 

If you place the engine on a powered track, it will come up in conventional mode, as it did for you, because it missed the watchdog signal.

 

However, if you turn on power when the engine is already on the track, it will be dark and silent, in DCS Mode.

 

This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!

Hey Barry,

 

Thanks for your reply and book recommendation, I actually already own that one If I set train on track, and then plug in power, I get the same scenario, I only hold it with one set of wheels on the track to avoid it going racing down the track and flying off.

 

Thanks for your input though, really appreciate it.

 

 

Edit: test 3, train on track, connecting power,http://www.youtube.com/watch?v=ZtyqlPruXIY , I kill power before it derails.

In the Dcs setup menu, make sure the dcs signal is on for all of your outputs.

Nicholas,

 

Do you have another PS2/3 engine and, if so, does it behave the same way?

Hey Barry,

 

I have a PS3 engine that works and operates fine on same track/tiu.

 

Thanks for the help.

 

- Nick

It's odd that it starts in one direction and then goes the other way.  I don't think I've ever seen that happen before.

yea pretty weird right. Does the fact that I can still find, and add the engine via the dcs remote (when unplugging the motor power) and send it signals mean the board isn't fried? Could this be happing because of a bad battery? Thanks so much for your input on this John and Barry.

Does this happen before you try to move it with the remote?  If you just power up the track, it takes off immediately even before you do a startup or move the thumbwheel?

If I place the train on the track, then connect my tiu to power, the train will go flying down the track and derail. Only way I can communicate with the train is to unplug the power to the motor, so it won't move and stay on the track, from there I can, find, add, reset, remove it from my dcs controller, but trying each of those didn't fix.

Well, the bad news is, the board is probably bad.  That sure sounds like a shorted driver, I had the exact symptom some time back.  I managed to replace the driver, but it's a difficult repair on a 5V board.  Since yours is a 3V board, it may be possible to repair it, but I'd recommend finding an MTH tech to diagnose the issue.

I think GRJ has the correct diagnosis.  If you listen carefully to a working PS2 board, there is a brief relay click when you first apply power.  This might explain the brief reverse motion in your last video before it takes off in forward.  So if you're able to talk DCS to the engine otherwise (sounds, lights) with the motor cable unplugged...and perhaps confirm you can change directions under DCS by listening for the relay click with sounds turned down...I'd think this would be a do-able repair.

Thanks stan, yea I can hear clicks when changing directions, so what would be the next step for repair, finding out which part needs to be replaced?

I'm pretty sure it would be the power MOSFET at Q9 that has failed.  That's the only part on there with sufficient power handling capability to be a motor driver.  It's on the bottom of the main board.

 

We'll wait for the MTH techs to confirm the likelihood, but that seems the obvious choice.

 

You can do a quick check of the MOSFET asfollows.

 

First connect DMM red lead to drain and black on the source.(meter should be on diode test mode).

In first case drain to source will be open.

Then connect meter red probe to gate and black to source and again connect the red probe to drain and black with source.

 

Now it will show the short circuit.

 

Finally, short the gate and source with some wire now again drain to source will show open circuit.

 

If it passes all those tests, that would indicate that MOSFET is probably good.

 

Thanks John! Appreciate your input, where can I contact a MTH tech?

Right here in the forum!   GGG is a tech, and there are a bunch of others.

 

Oh wow! That's awesome. Such a great forum, thanks guys.

Check out some more of my trains vids. http://www.youtube.com/channel...D0RAnA?feature=watch

See if you can you run the engine in conventional mode with a z-controller if you have one (disconnect the TIU). I had a similar problem with the same subway just not that bad because I was able to control it in conventional mode since all the power was not sent to the track like in DCS mode. If you can control the engine in conventional mode, or it runs better I would do a very very good inspection of all the wires in the engine. Pay closes attention to the ones connected to the motors, check under rubber bands that are holding the wires on the motor. Check twisted wires in the plastic wire ties, all wires by the speaker and in the yellow cap. Also check the red and black wires connected to the truck. Make sure that there is no exposed wires touching the black frame of the engine. In my case my engine would take off at full speed on curves and would not stop unless I cut power. There was a pinch in a wire under the battery that touched a screw when the engine would make a turn causing a short and it would take off. Taped up the wire and everything was good.

I have seen this before.  John has it.  The possibility is a burned trace on the PS, a bad diode or the FET or shorted motor leads.  I did not watch your video I don't have the time:-)  By removing the motor connector there is no longer a load on the PV and relay.  This allows the rest of the board to work.  I have successfully repaired the motor fet, the fet that controls the motor fet, and the microprocessor that controls it.

 

If you know it is the board set and feel comfortable nothing is wrong with the engine motors and motor wires, you could just send the boards.  Otherwise best to send the engine.  Email is my profile.

 

Good job John, You are getting good at this:-)!!!  G

I've got a ways to go, but I've seen that behavior before.