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MTH, in collaboration with the AGHR Model Railroad Club, has researched, tested and developed a preventative modification for all TIUs, although Rev. L TIUs appear to be those most often affected, to prevent failure of the DCS signal generators in heavy use situations. This solution is discussed in the attached document, Service Bulletin 05-22-18a.pdf. You may view or download the document using the link at the end of this post.

Note that if you are not an MTH Authorized Center technician (ASC) and you damage any TIU while attempting to install the modification, any and all warranties regarding the TIU so affected are voided.

Many thanks to MTH and AGHR for their diligence in bringing about this modification.

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Last edited by Barry Broskowitz
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I'm not clear as to whether this mod SHOULD be done or COULD be done on my rev L TIUs.  Should it be done to fix the 10-11-12 mod, or for any REV L TIU whether past-modded or not?

IF MTH has recognized that there is an under-rated part in their product, does that mean they will do the mod for you at no charge or pay an ASC to do it?

Not trying to create an issue, just trying to determine if MTH is saying, "Your REV L TIU has a defective part that will not handle all TVS issues so we will fix it for you", or "Your REV L TIU has a defective part that will not handle all TVS issues so get it fixed at your expense, if you feel like paying for the parts and labor"

I do appreciate the work done by AGHR and MTH in identifying this issue. If an issue that has been discovered and documented by a company and might occur,   on most products you'd get a notice and bring it in for a fix at no cost.

Last edited by eddiem

Joe,

Not sure.  Is "heavy use" defined as use ABOVE the rated loads that are advertised in the specs, or WITHIN the advertised specs?

Seems to me that if you're using the TIU with loads that it's advertised to handle, the mod should be covered by MTH.

I think our club TIUs, my modular TIUs, and my personal TIUS are used with within-spec loads, but it sounds like they might fail to protect from some TVS events, no?  In each of theses situations, we've seen the error messages indicated, while the remote-measured signal levels were 8-10 in the same operating session.... probably run at about 80% of advertised load.

Last edited by eddiem
NHVRYGray posted:

I will be in need of a new TIU shortly.  Any ideas when the new mod will be available to buy and how to identify that the TIU is the latest version?

I really don't want to buy a TIU and then have to send it back to get fixed, if it means waiting, I'd rather wait.

I don't see anything in the document that suggests that this "fix" will be included in future TIUs.  Much like the questions I pose, the document doesn't seem to address whether current or future TIUs will have the new parts incorporated, or how the clearly defined issue (by MTH) will be addressed for customers.

Question: At some point did MTH start adding the 10-11-12 mod to all new Rev L TIUs?

As noted, MTH doesn't stock the parts that are required for the new mod.

I know we're talking toy trains here but, if a company defines a problem with one of their products and determines that there is a viable solution to address the problem, I think it is their responsibility to do what is necessary to resolve the manufacturing "defect" - that's what this is, as is clearly obvious in their published documentation provided above. 

Maybe they will....additional information required.

eddiem posted:

I don't see anything in the document that suggests that this "fix" will be included in future TIUs.  Much like the questions I pose, the document doesn't seem to address whether current or future TIUs will have the new parts incorporated, or how the clearly defined issue (by MTH) will be addressed for customers.

Question: At some point did MTH start adding the 10-11-12 mod to all new Rev L TIUs?

As noted, MTH doesn't stock the parts that are required for the new mod.

I know we're talking toy trains here but, if a company defines a problem with one of their products and determines that there is a viable solution to address the problem, I think it is their responsibility to do what is necessary to resolve the manufacturing "defect" - that's what this is, as is clearly obvious in their published documentation provided above. 

Maybe they will....additional information required.

MTHRD posted in another thread that going forward all newly manufactured REV. L TIU's will have this update applied.

I have two REV. L TIUs and both have the first mod(ification). Both are working just fine, and after running a scope on them they do not exhibit the problems pointed out in Adrian's other thread. If it ain't broke then why should MTH recall all REV. L TIU's if they are working just fine.

I put this in the same category as the transmission in my wifes new car. Turns out there is a service bulletin on it that states a sensor may fail and cause the car to shift erratically between 1st and 2nd.  This is a fix that is only applied if the problem is occurring on the vehicle, not return all units to the dealerships and fix immediately. My truck has about a dozen service bulletins like this that will only be addressed if the failing part is actually failing or it is convenient for the mechanic to replace / repair the part. But I don't expect FORD to take out my transmission and spend hours tearing it apart to address a minor issue of the speedometer jumping from 0 - 5 MPH when accelerating. If something else happens that warrants them to remove and disassemble the transmission, then yes, install the updated part.

My feeling, any REV. L TIU that is return to MTH for any reason should have this fix applied beings that the TIU will be apart and it is handy for a qualified technician to replace the needed parts for almost nothing. If a TIU is suffering from this problem specifically, MTH should repair it at no cost. I don't believe that every TIU should be returned and this expected to be updated for free.

 

Last edited by H1000
clem k posted:

Describe heavy use ?

Clem

THIS IS REAL:

12:15pm  Train 1 derails on switch 5
12:17pm  Train 2 derails on switch 16
12:19pm  Train 3 hits Train 1, both derail
12:22pm  Train 4 is placed on the track while power is on and sparking all over
12:23pm  Train 4 derails on switch 1
12:29pm  Train 3 hits train 4, both derail
12:33pm  Train 1 derails on switch 5
12:35pm  Train 3 hits train 2, Train 2 derails
12:41pm  Emergency stop
12:43pm  Train 1 & 2 derail on switch 5 and 6 respectively
12:45pm  Train 3 hits train 1

"...the thing about trains is they are on this thing called a "track" and that makes it possible to look ahead and determine where a train will go before it goes there. Using this powerful concept you can make the train go only where you want it to go yet somehow every Saturday I come in here and..." - AJT 2017

Last edited by Adrian!

Thanks for posting, Barry.

I note the tech bulletin also addresses another issue that has plagued TIUs since Rev G:  the tendency of nuts on the terminals to loosen.  I have added internal star washers and lock nuts to overcome this, rather than use Loktite.  But I encourage y'all not to overlook this item.  Be sure not to overtighten.

Robert,

Is this addition appropriate for Revs earlier than Rev L?

From Jason's post on the other thread:

The vast majority of TIU's we've seen come through Service as well reports from the field have been on Rev L TIU's. Only the Rev L TIU's have the old mod applied.

For any follow-up questions in this regard, I refer you to Jason.

Last edited by Barry Broskowitz

Gentlemen,

   I use the gold plated Banana plugs have never had a problem with the nets coming loose in this manner.  I have 2 TIU's and run my trains quite a bit, so far no problems with the Rev L.  The only problem I ever had was on the very 1st TIU that was ever made, no fuses back then.  After Barry's advise to use 10 Amp fuses or Resettable Breakers between my Transformers and the TIU, I have never had a single problem, especially with the Rev L.   Thanks to MartyE's upgraded technology, all works like new.

Thanks much guys I really appreciate it!

PCRR/Dave

Work on the Pine Creek Train Room Continues.

DSCN2439

 

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Last edited by Pine Creek Railroad

An interesting piece of information from the memo is that MTH used Seitz & Associates to design the DCS system.

If one looks at the Seitz & Associates website, under their designs page, there is one showing their MTH products.    http://www.seitzassoc.com/mth.html

It would be fun to know if Seitz just implemented and prepared for manufacture the MTH designs, or actually did more of the DCS design.

I assume the Seitz has such an iron-clad nondisclosure agreement that we'll never know.

Also interesting is the client is TRACKRL

-Lad

The problem: (as defined in the service bulletin) "degraded or total loss of transmit DCS signal to the engine giving you Check Track or No Engine On Track error message when adding or running PS2 or PS3 engines."

So, if I have a layout connected to my TIU and I get the error messages specifically listed when I run PS 2 and 3 engines, my TIU needs the mod, right?

I agree with H1000.

H1000 said, "If a TIU is suffering from this problem specifically, MTH should repair it at no cost."

The only concern I have is how/when it gets fixed!

Adrian, What you describe is not a TIU issue, it's a set of really bad switches!  That's not "heavy use" that's "heavy abuse."  You listed 12 short circuits in 30 minutes!  I'm not sure I would expect MTH to add this mod for free, given the beating you're giving your TIU.

On the other hand, I think a TIU that has "degraded or total loss of transmit DCS signal to the engine giving you Check Track or No Engine On Track error message when adding or running PS2 or PS3 engines." should be repaired at MTH's expense.... it's a defective product!

My concern remains... MTH has issued a mod to fix a specific problem, but has not indicated how the affected TIUS will be repaired, under what circumstances, and at whose expense.

Eddie,

So, if I have a layout connected to my TIU and I get the error messages specifically listed when I run PS 2 and 3 engines, my TIU needs the mod, right?

Not necessarily.

There are a variety of reasons, other than a defective TIU, that will yield those and other error messages. These reasons typically fall into the following categories:

  • Poor wiring
  • Convoluted and track topology
  • Loose transceiver in the remote and/or TIU
  • Engine problems
  • Dirty tracks, wheels or pickup rollers
  • Operator error.

I'd suggest that you revise your statement above to be something on the order of the following:

So, if I have a short test track connected to my TIU with the TIU connected to the DCS Remote, and I get the error messages specifically listed when I run a known, good PS2 or PS3 engine, my TIU may be a candidate for the mod.

Regarding your statement:

On the other hand, I think a TIU that has "degraded or total loss of transmit DCS signal to the engine giving you Check Track or No Engine On Track error message when adding or running PS2 or PS3 engines." should be repaired at MTH's expense.... it's a defective product!

I would agree that MTH should foot the bill for the repairif the TIU is under warranty, just like for any other usage-inflicted damage to the TIU.

All of the above is just my opinion and is not based on any discussions with MTH.

Last edited by Barry Broskowitz
Adrian! posted:

I love that they used my quick ms-paint doodle in the bulletin. I hope I drew it right!

Adrian, As they say imitation is the highest form of flattery.

Adrian! posted:
clem k posted:

Describe heavy use ?

Clem

THIS IS REAL:

12:15pm  Train 1 derails on switch 5
12:17pm  Train 2 derails on switch 16
12:19pm  Train 3 hits Train 1, both derail
12:22pm  Train 4 is placed on the track while power is on and sparking all over
12:23pm  Train 4 derails on switch 1
12:29pm  Train 3 hits train 4, both derail
12:33pm  Train 1 derails on switch 5
12:35pm  Train 3 hits train 2, Train 2 derails
12:41pm  Emergency stop
12:43pm  Train 1 & 2 derail on switch 5 and 6 respectively
12:45pm  Train 3 hits train 1

"...the thing about trains is they are on this thing called a "track" and that makes it possible to look ahead and determine where a train will go before it goes there. Using this powerful concept you can make the train go only where you want it to go yet somehow every Saturday I come in here and..." - AJT 2017

It looks like AGHR needs to take a safety timeout.

Adrian, Your work on this issue has been impressive. Your collaborators deserve a little notice as well.  Pat B.

Will this mod be covered under warranty? The variable 2 channel on my month old Revision L TIU has stopped putting out a strong DCS signal after a derailment that popped the 7.5 amp fast blow fuse in line between the transformer and the TIU. On the loop connected to variable 2 only the block with the shortest wire run has a signal strength of 10. Every other block either has a strength of 1 or "Out of RF Range" displayed on the remote. Hooking the loop up to fixed 2, fixed 1, or variable 1 gets a signal strength of 10 everywhere, so there is a problem on variable 2. I'm betting the tiny TVS on variable 2 failed with the derailment, but I don't want to open the TIU and check as it's under warranty. I just want to be sure that the tech will preform the modification in the bulletin while the TIU is in for warranty repair. 

At P&P we are replacing the optocouplers with a hot air solder machine, so far we have repaired 2 TIU's which has paid for the hot air machine, and purchased the replacement optocouplers so we have enough for nearly 50 repairs due to a fortunate purchase last year at an auction. Only time will tell if this is sustainable, but we are hard on TIU's and having in house repair keeps them available so our layout continues running daily.

There are no indicates of the internal mod level on the case of the TIU.  None of the "fixes" that MTH has installed to prevent the failure of the 74ACT244 chips for the DCS signal drive have been effective.  There was a rather extensive thread where we discussed all of this in some detail.

Weak DCS signals, Failed TIU Output Drivers, and Design Solutions devloped under collaboration between AGHR and MTH

I have created a fix that addresses the issue of the 74ACT244 drivers getting zapped, but I haven't had the time to pursue it to it's logical conclusion.  TIU DCS Generator Transient Suppression Board.

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