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I've got a PS1 diesel sitting here that was upgraded with a MTH PS3 diesel kit that has an issue. The person who installed the kit neglected to put the smoke elements in parallel before it was powered up. So now, if the smoke unit is hooked up, the fan constantly runs with power applied and the locomotive can't be found by the TIU. If the smoke unit (both the resistors and fan) is unplugged the locomotive will operate fine under DCS. So my question is what got fried on the board and is it repairable? If not I'll have to tell the guy the board needs to be replaced to get the smoke function back. The smoke unit needs to be corrected to work with the board either way, but that's an easy fix.

Original Post

if the tech that did the upgrade did not make the change to the ps1 smoke unit that's why the board got damaged, there is a isolation procedure you must do by the diesel kit upgrade book and traces have to be cut or you will damage the board! read page 24 of upgrade manual!!!

 

Alan 

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deisel upgrade kit instructions!
Last edited by Alan Mancus

If he modified the smoke board by cutting trace or removing components but forgot to parallel resistors that would not cause any issue.  You would have a 32 ohm resistor instead of an effective 8 ohm.  If the smoke fan motor has issues that would be a draw on the 5V circuit and potentially cause the PS-3 board not to work correctly.  Since board bounces back and works fine with smoke disconnected you might not have board damage just bad smoke fan motor.

Now if components not removed or modified on smoke  G

GGG posted:

If he modified the smoke board by cutting trace or removing components but forgot to parallel resistors that would not cause any issue.  You would have a 32 ohm resistor instead of an effective 8 ohm.  If the smoke fan motor has issues that would be a draw on the 5V circuit and potentially cause the PS-3 board not to work correctly.  Since board bounces back and works fine with smoke disconnected you might not have board damage just bad smoke fan motor.

Now if components not removed or modified on smoke  G

The smoke unit resistors were not put in parallel, i.e. the traces on the smoke unit were not cut and the smoke unit was connected to the board and powered up. If the smoke unit fan and resistors are plugged in the board will not power up and the fan on the smoke unit will constantly run. With the smoke unit (both fan and resistors) disconnected the board will power up and run fin in DCS and conventional. I assume this damaged at least the smoke circuit on the board. Is that repairable or is the board trashed?

The locomotive came to me like this. I am attempting to see if it is repairable for that person. 

Last edited by Lou1985

Important point.  Was the smoke unit plugged into track power with the PS/3 board connected?  In other words, did they not disconnect the track power connection and power it up with the PS/3 wiring connected?  If so, they could have certainly damaged parts on the PS/3 board!

If they just didn't cut the traces and powered up just the PS/3 board, I suspect it would have done much less damage.

Last edited by gunrunnerjohn
gunrunnerjohn posted:

Important point.  Was the smoke unit plugged into track power with the PS/3 board connected?  In other words, did they not disconnect the track power connection and power it up with the PS/3 wiring connected?  If so, they could have certainly damaged parts on the PS/3 board!

If they just didn't cut the traces and powered up just the PS/3 board, I suspect it would have done much less damage.

I've attached a picture of the type smoke unit used in the locomotive. In the picture (from MTH's instructions) the trace that was supposed to be cut was not. The smoke unit was wired correctly except for the cut not being made and then the smoke unit was turned on. There's a big note about that damaging the board in the instructions if the cut is not made to the trace...… Is the damage that caused repairable or is the board trashed?

Capture 

 

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Ah nuts. That's a lot of FETs. You got one you're willing to part with 😁. I'll try and pop the board out later and see if any traces are damaged. If they are then it's trashed. 

Funny thing is with the smoke unit fan connected the board won't power up and the fan constantly runs. Disconnect the fan and everything powers up and works fine. 

Last edited by Lou1985
gunrunnerjohn posted:

I'm guessing you'll need the fan FET as well.

There's no certainty that other stuff hasn't died in the process, but you have to start somewhere.

I don't have any of the FET's, but if you buy 100, I'll take a few.

Well I'll find out when I pop the board out of the locomotive. Same part number for both the smoke resistor and smoke fan FET?

Well the smoke FET really died. Can see where it melted in the attached picture. It's rather tiny and soldering something that small and precise is a bit beyond my skill range and equipment. Board is going to a local MTH tech for a check and possible parts replacement, if the rest of the board checks out ok. Guy had another board (from another kit) so in the meantime I installed that, along with wiring the smoke unit correctly and replacing both resistors in the smoke unit. Loaded the correct PS3 chain and sound files and it works perfect. 

20200215_140715

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Lou1985 posted:
gunrunnerjohn posted:

Those smoke FET's are easy, wait until you try the really small parts.

Sometimes it's easier/cheaper to pass the work to someone with the proper equipment/skills then try yourself and screw something up worse. Gotta know your limits 😉. 

Yup said the famous Dirty Harry - LOL

Yes sir, that's why GGG s getting my ps1 loco to look at.

That smoke unit is not typical for diesels, rather for articulate steam and some odd diesels. It is a PS-1 that has the electronics under it and gets three wires.

Each smoke unit can be different requiring different mods.  In either case the first thing to do is get the electronics of the PS-1 off the traces. Either a cut, or removal.   Then the PCB needs to be inspected to see if an additional cut is needed.  Typical Diesels do not, though some do on the unique diesel types like the picture shown.  Hence the need to check it with an ohm meter to see that you have 8 ohms, not 16, 32 or in this case 0.    G

The other reason to use a transformer with amp meter.  It was only a PV short.  He should have seen current spiking at which time you turn it off.  Most problems with those types of PV shorts is folks leave the engine powered up until a fuse or breaker trips which is why the fet and many times the traces get cooked. G 

GGG posted:

The other reason to use a transformer with amp meter.  It was only a PV short.  He should have seen current spiking at which time you turn it off.  Most problems with those types of PV shorts is folks leave the engine powered up until a fuse or breaker trips which is why the fet and many times the traces get cooked. G 

Oh yeah it would have been helpful. Had to replace a couple melted wires in the harness as well. I'll be sticking the repaired board in another project for the guy when it comes back. I told him to let me deal with the smoke units from now on.....

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