Skip to main content

So I have finally experienced what I have read about......an MTH New Haven ABA set (20-2238-1)PS2 5V board blew a capacitor in dramatic fashion! So from what I have read, the only way to remedy is to upgrade using a PS2/3 Diesel Upgrade kit. I have upgraded only PS1 steamers to this point. It looks like only one of the A units has the PS2 board so I'm assuming this is where the upgrade PS2/3 board goes. There is a board in the other A unit. Does anything need to be done to this board? Thanks for any guidance out there!

Last edited by LT1Poncho
Original Post

Replies sorted oldest to newest

@LT1Poncho posted:

So I have finally experienced what I have read about......an MTH New Haven ABA set (20-2238-1)PS2 5V board blew a capacitor in dramatic fashion! So from what I have read, the only way to remedy is to upgrade using a PS2/3 Diesel Upgrade kit. I have upgraded only PS1 steamers to this point. It looks like only one of the A units has the PS2 board so I'm assuming this is where the upgrade PS2/3 board goes. There is a board in the other A unit. Does anything need to be done to this board? Thanks for any guidance out there!

I've done no less than 6 of these sets in the last couple of months. Seems like a lot of folks got them out and that with boards being available (and every single one of the PS2 5V boards dead or dying) led to lots of upgrades.

You simply need a 5V style upper stacker board and standard lower stacker board set in the lead engine, and then in the trailing powered unit- nothing- the factory "slave" board works as expected.

I will say this, the PS3/2 stacker is a tighter fit. It's longer than the PS2 5V board. I removed and remote mounted the rectifier on the lower PS3 board and placed the PS3/2 stacker board laying on it's side using high quality double sided foam tape. I then heatsinked the remote mounted rectifier.

Again, your problem will be, the space between the smoke unit and front motor is barely, and I do mean barely enough room to fit a PS3/2 stacker board set and wiring.

Attachments

Images (1)
  • mceclip0

Just checked MTH parts and sales, and the stacker 5V set of boards are out of stock. They still have 5V upper boards, but $31 list is pricey.

As such, your best bet is buy a steam upgrade kit (contains a PS3/2 3V connector based stacker). Then kind of 2 choices, you could remove one wire at a time from your 5V connectors and insert them into the 3V connector shells, or you could use the heat gun trick, remove the old 5V connectors sockets from the dead 5V board, and use them over the pins on the 3V upper stacker board.

Again, cheapest best way forward- given what's in front of us as being available, is get the steam upgrade kit with gives you board, mounting bracket, speaker, wiring harness for parts, and also 6V bulbs- as spares.

Attachments

Images (1)
  • mceclip0

Also, if we are on the topic, I then remove the 2 FET heatsink metal strips from the dead PS2 5V board, and just for good measure (unsure if this helps, but hey every little bit right?), and use them on the analog PS2 style slave board for the motor drive FETs on that board. I don't know that heat is the main or only cause of failures in this board- but again, they heatsinked the FETs on the lead engine, so it seems logical to me to help on the trailing engine.

Again, a semi common failure is a runaway slave board that the instant track power is applied tries to run in one direction.

There are a bunch of things that can damage this board- tether connector plugged in upside down, rubbing or wire short, blown lead board results in blown slave board, jammed motor, or some other problem.

I have no proof this fixes or solves things, but I feel better knowing I took parts going into the trash can (dead 5V board) and tried to reuse and improve what I saw as possible shortcomings.

Attachments

Images (2)
  • mceclip0
  • mceclip1

@Vernon Barry I can’t thank you enough. I will purchase part AE1003G353V with the tethered board. I am not sure I understand your 2 options fully: “Then kind of 2 choices, you could remove one wire at a time from your 5V connectors and insert them into the 3V connector shells, or you could use the heat gun trick, remove the old 5V connectors sockets from the dead 5V board, and use them over the pins on the 3V upper stacker board.”

I may pick your brain when I get into it and get started! Thanks so much once again. I knew this day would come, and I look forward to learning this skill.

Mike

@Vernon Barry I have started to replace the blown 5V board. I have decided to punch out the wires from the 5V connectors and plug them into the 3V connectors since I have some experience with that method. I have attached a few photos.

First to this point, the colors of the wires going into the largest connector have been the same. Now they are not, as you see from the photo. I am assuming this doesn’t matter!? And will it matter for the other connectors??

Second, I am not sure how to handle the wires coming directly off the 5V board which connect to a connector on the chassis?????



thanks for your help!

Mike

Attachments

Images (3)
  • IMG_0832
  • IMG_0834
  • IMG_0833

Ignore this wire set and remove the regulator from the chassis- no longer needed.

Again ignore and remove this remote regulator for the old 5V board.

Screen Shot 2023-12-29 at 9.10.23 AM

On the other connectors, color is not important as position- so just do them one wire at a time. MTH may not always have used the same color wire, but the locations on the board remained the same. Again put the connectors side by side, oriented the same way, and then just move one wire at a time, being sure to skip any missing wire locations. Pictures before and after can help you catch mistakes.

Attachments

Images (1)
  • Screen Shot 2023-12-29 at 9.10.23 AM
@LT1Poncho posted:

@Vernon Barry thanks! One last question (at the moment). Just wanted to confirm, I CAN REMOVE the battery and its holder? I was thinking about mounting the tethered portion of the board in this area!

Yes, remove the battery, holder and especially the 2 pin wiring harness for the battery.

Edit, forgot one important picture related to the above comment!!

PS2 board replacement | O Gauge Railroading On Line Forum

Here, I just took apart my own B&O FA-2 set from the same MTH series for you to snap some pictures. It too was the PS2 5V and upgraded by me to PS3 using a PS3/2 stacker board set with 5V connectors. I remote mounted the rectifier on the PS3/2 stacker set.

I'm not saying this is the best way- just the way I found to jam it in there and make it fit. Key point is all the wiring clears those center body posts (2 body screw locations in the middle, diagnal share holes with the fuel tank and speaker mounted below the frame.

IMG_4016IMG_4017IMG_4018IMG_4019

Attachments

Images (4)
  • IMG_4016
  • IMG_4017
  • IMG_4018
  • IMG_4019
Last edited by Vernon Barry

Also, I mentioned taking the heatsinks off the motor drive transistors on the old dead PS2 5V board, and reusing them on the analog slave board used in the trailing A powered unit.

Before- salve board left, PS2 5V board from lead engine right.

After



IMG_4020IMG_4021IMG_4023

Again, simply taken off desoldering from the original now dead board in the lead unit.

Attachments

Images (3)
  • IMG_4020
  • IMG_4021
  • IMG_4023

Well…….things did not go so well. Started up fine, smoked well, sounds were amazing. Started her out slow and she took off at full speed for some reason, took a leap, and tail unit didn’t make it. Head unit is cracked but can be repaired. Still starts up but takes off at full speed. Not sure where to go from here except the bar. Could it be a bad chain file? I loaded the Diesel standard chain file? No idea



mike

Attachments

Images (1)
  • IMG_0836
@LT1Poncho posted:

Well…….things did not go so well. Started up fine, smoked well, sounds were amazing. Started her out slow and she took off at full speed for some reason, took a leap, and tail unit didn’t make it. Head unit is cracked but can be repaired. Still starts up but takes off at full speed. Not sure where to go from here except the bar. Could it be a bad chain file? I loaded the Diesel standard chain file? No idea



mike

You loaded the one from here- specific to PS3/2 stacker boards right? https://mthtrains.com/chainfiles

I have checked the wiring and all seems fine. I am going to adjust the tach sensor closer to the flywheel. Maybe it got moved. I am confident I have the correct chain file, but could the sound file affect this? I attached a photo of the sound file I loaded. Its a PS2 and the only F-2 ABA I could find. Should I try a PS3 file froma F-3?  There are no PS3 F2’s

Mike

Attachments

Images (1)
  • IMG_0250
Last edited by LT1Poncho

FWIW, seeing your shells cracked, I feel bad you ran into a problem. This is why I test at the workbench with the engine on it's side on a soft towel- using alligator clip leads to either a TIU for control and programming or a Zcontroller for conventional testing.

Again, just as a guess, the tach reader could have been subject to failure from a 5V board dying and wild voltages as it died.

Last edited by Vernon Barry

FWIW, seeing your shells cracked, I feel bad you ran into a problem. This is why I test at the workbench with the engine on it's side on a soft towel- using alligator clip leads to either a TIU for control and programming or a Zcontroller for conventional testing.

Again, just as a guess, the tach reader could have been subject to failure from a 5V board dying and wild voltages as it died.

Totally my ignorance. I have a small test track on which I tested the sound and smoke etc. I cannot really test motion on this small track. Now I see what you use alligator clips etc, and I should have a way to test motion.  Having upgraded a fair amount of PS1 steamers to PS2/3, I know to watch for these types of things. I just didn’t plan for a take off, wasn’t ready to grab it. Now I have an AB instead of an ABA. Maybe someday I can locate a shell.

Gonna have my coffee and switch out a spare tach reader. If that’s a no go, I’ll load your sound file. If that’s a bust, has to be the board.

Mike

You need something like my test track.

The step allows me to put a locomotive on the rollers and hook up the tender normally for a full test.  The test rollers are a must for full function testing on the bench.

Very nice, and you can tell you are a professional! Did you fabricate the test rollers or are they available somewhere to buy?

Mike

@LT1Poncho posted:

I swapped the tach reader....no change. I reloaded the chain file.....no change. I loaded the other sound file.....no change. I tested it in conventional, and it takes off on just minimal throttle. I guess I have a bad board??

I'm not saying it's not a bad board, but we sure hope it's not.

You did change connectors and this is the original wiring harness. The 7 pin connector is both power into the stacker and tachometer reader (standard PS2 wiring and connector format).

Screen Shot 2023-12-30 at 11.07.46 AM

Attachments

Images (1)
  • Screen Shot 2023-12-30 at 11.07.46 AM
@LT1Poncho posted:

Very nice, and you can tell you are a professional! Did you fabricate the test rollers or are they available somewhere to buy?

They available, though the JAK ones I have I don't think are around anymore.  I know that Micromark has rollers, but I don't like them as much as the ones I use.  Folks have also published specs to build them, but that seems a ton more work without all the tools and materials for a one-off project.  I have sixteen roller blocks, that's more than enough for any of the stuff I work on.

I'm not saying it's not a bad board, but we sure hope it's not.

You did change connectors and this is the original wiring harness. The 7 pin connector is both power into the stacker and tachometer reader (standard PS2 wiring and connector format).

Screen Shot 2023-12-30 at 11.07.46 AM

Here is my 7pin connector. Looks correct to me. The other engine chassis ground wire and roller wire are connected with wire nuts as they were from the factory.

Mike

Attachments

Images (1)
  • IMG_0838

Yep, matches up. Edit- note, I flipped your picture to better line up to the schematic snippet labeling. Again, it looks right

It's unlikely to be the other connectors.

8 pin one is basically what I call aux lighting- mostly marker lights and other lights like MARS. It can be unplugged and everything else would world normally.

The smoke one you said worked- so it's hard for that to be wrong.

Motor 5 pin connector I don't know how that could be wrong and do what it's doing. It would either short out or run the motor wrong direction- but not runaway.

Attachments

Images (1)
  • mceclip0
Last edited by Vernon Barry
@rplst8 posted:

From the looks of the picture of the wrecked locomotive, there is no tach strip on the flywheel!

No, that is the trailing unit with an analog slave board- no tach.

Edit
It's good that you are looking and trying to help.

This is a shot from his lead unit that does appear to have an tach striped flywheel and the sensor- it's just not working. (flywheel just under hand).

Last edited by Vernon Barry
@rplst8 posted:

From the looks of the picture of the wrecked locomotive, there is no tach strip on the flywheel!

I just saw and read this entire thread.  I am in agreement; I can't see the tach strip either.  Edit:  Thank you, Vernon for the answer that we are looking at the other unit.

That said, thank you Mike for brining up this topic.  Your questions have been great, and I certainly am sorry you had the accident with the broken shell.

Thank you Vernon and John for your answers.  This situation certainly could happen to one of my 5v board engines.  Yes, I have been using rollers when testing my engines.

Last edited by Mark Boyce

Yep, matches up. Edit- note, I flipped your picture to better line up to the schematic snippet labeling. Again, it looks right

It's unlikely to be the other connectors.

8 pin one is basically what I call aux lighting- mostly marker lights and other lights like MARS. It can be unplugged and everything else would world normally.

The smoke one you said worked- so it's hard for that to be wrong.

Motor 5 pin connector I don't know how that could be wrong and do what it's doing. It would either short out or run the motor wrong direction- but not runaway.

Yes my thoughts exactly. Those are the two connectors (7 and 12) where the largest errors could occur. The tach strip is in place on the head engine. Thanks for the suggestion. I have swapped out the speaker for a 4ohm. Changed the front coupler. No change. Head scratcher for sure. Thanks everyone.

Mike

Make sure the PS-32 adapter board is fully seated to the PS-3 stacker.  Make sure not a broken wire.  Test continuity from Tach solder joint to 7 pin connector.  If you have another board set you can swap the top adapter board.  That has the speed control chips for the PS-2 chip.

Also ensure 7 pin fully seated.

Make sure you do not have a motor lead (white if it moved forward) shorted to chassis ground.  At motor solder joint, or damaged wire going to 5 pin.

This is why I test in conventional first where I can control voltage down around 10V.  Much harder to run away at 10V.  G

Add Reply

Post
The DCS Forum is sponsored by

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

×
×
×
×
Link copied to your clipboard.
×
×