PS2 3 Volt Engine a Runaway

 Mine sped up on turns when the tether had some strain on it. Then the headlight stopped working. Resoldered the pins on the engines PCB where the tether plugged in. Just basically touched each pin with a tinned pencil type soldering iron with the tether in place.  Really tough to see anything wrong. Solved all it's issues.

Already did that

When you state no speed control, is that after you increase the remote's speed?

or is that anytime it sees power?

The motor wires aren't touching the casing?

can you test for continuity with each wire ( like the coupler) to the board and to the frame? ( I see you stated that you tested for continuity)

could the engine's tether socket wires be touching the frame or shell? (when the shell gets screwed on tightly)

G could probably help best if the fets are shorted.

Engineer-Joe posted:

When you state no speed control, is that after you increase the remote's speed?

or is that anytime it sees power?

The motor wires aren't touching the casing?

can you test for continuity with each wire ( like the coupler) to the board and to the frame? ( I see you stated that you tested for continuity)

could the engine's tether socket wires be touching the frame or shell? (when the shell gets screwed on tightly)

G could probably help best if the fets are shorted.

Startup the engine, all functions at idle work as expected, scroll up to 1 or 2 mph and the engine accelerates to full speed.  I have checked all continuity, the tether socket, the tether and run without the shell.  No change.

Tach Tape, Gap and Engine Mux.  The tender mux does not control speed.  The 5V may come from the engine mux though.  If smoke works in idle, than tracing 5V, Blue ground and orange tach return through the engine harness back to engine. Also, everyone and a while a new tach reader is bad, so you may have to test a third.  G

I have ran into tack board being bad and also ic on board but since you tested on test rig I would suspect tack board or wiring in engine ! good luck

Alan

GGG posted:

Tach Tape, Gap and Engine Mux.  The tender mux does not control speed.  The 5V may come from the engine mux though.  If smoke works in idle, than tracing 5V, Blue ground and orange tach return through the engine harness back to engine. Also, everyone and a while a new tach reader is bad, so you may have to test a third.  G

Would the engine mux be the little board that lights a smoke plug into.  That is the only board in the engine.  I have tested continuity from the PS2 board all the way to that little board and it all shows good.  Since I'm running with out the shell I have no idea on the smoke, will have to hook the shell up to see.  I have good connections on that big (and I mean BIG) blue wire.  BTW does it have to be that big .  I have extra tach readers so I can try another one, .  I hate soldering on those little things!  Thanks for the help

P.S. What is the difference between the Tach Reader with a hole and the one without the hole?

Charly posted:

P.S. What is the difference between the Tach Reader with a hole and the one without the hole?

As near as I can tell, one has a hole.   I'm sure it was for some special mount, but they have the same sensor and wiring.

I would also look at the tach.  Charly does what I do early on in testing.  Separate and test the board in the tester so you will have a good starting point.  The issue will be a board issue or a chassis issue.  This is a chassis issue.  I would hook the engine to the tender (body removed)  and check continuity from the tach reader back to the PS2 board.   Many times on the engine 10 pin connector you need to look at the top of the pins on the pad.  Touch each one up with a hot solder iron.  As the trains get older, this is showing up more often.  

Cheryl,  Yes that is engine mux.  Your problem may be that your not running with shell!  I assume that means you have disconnected the 10 pin between shell and chassis?  Many (not all) 3V Mux engines have the 5V and Blue ground go up to the engine MUX via that 10 pin connector and the 5V and Ground for the tach come back down through it to the tach reader.  So if you do not connect the 10 pin shell wiring, the tach reader does not have power.   You need to trace wires to be sure, but that may be your problem. G

Is there any way to test a tach reader itself, as opposed to trying a replacement?

You can bench check them, but you have to wire up a meter and power to do it.  You also need current limiting for the emitter.  It's probably not for the average person to try...

Thanks for all the info guys, really appreciated it.  Will be tackling this problem again on Friday.

Just an FYI, followed the suggestion of adding the shell and she ran like a charm.  At some point I need to put a new receiver board in it and I plan to change the tether from angled to straight, to relieve strain, but other than that we're good to go.

 Your welcome!  G

Hate to beat a dead horse but...  this engine has failed again.  Have completely tested the tender and every thing seems to be fine.  Wires show continuity and board is flawless on the PS2 test fixture.  Still need to go through the engine once more and put the new receiver board in.

Could this engine possible have blown the tender mux board again.  All functions work, but engine will not move.  The smoke unit shuts down to start puffing but the engine does not move.

Any ideas, thoughts or suggestions would be appreciated

Step 1:

Step 2:

Step 3:

KD

Ha, ha, DKDKRD,

Do you hear the relay on the PS2 board "click" when you change direction? 

You can measure the DC voltage at the 5-pin motor connector on the bigger PS2 board in the tender and follow the motor voltage thru any wiring, tethering, mux boards, or whatever to the DC motor in the engine.  If the nothing is moving you should read full-scale DC voltage as the PS2 board tries to get the engine started even for a command as small as 1 sMPH.  Full-scale DC voltage should be 30-40% more than the AC voltage.  The DC voltage as measured at the 5-pin motor connector should reverse polarity when you change direction (hear the relay click).

Could this engine possible have blown the tender mux board again.  All functions work, but engine will not move.  The smoke unit shuts down to start puffing but the engine does not move.

Any ideas, thoughts or suggestions would be appreciated

 Question  for the repair guys.......Would  another blown "mux" board stop the engine from moving? wouldn't it still move but out of control?

I'm sure you've tried but try another feature or factory reset. You sure the motor leads are completely plugged into the main board.?

How are the pins at engine side tether connection?  Any broken motor leads?  G

New Receiver Board solved the power problems.  Engine is residing happily on the layout now.