Model Train Journal

Anyone who doubts the kludginess of the DCS system should read this thread on the OGR Forum.

https://ogrforum.ogaugerr.com/topic/wea ... 1160839697

I can only imagine the firestorm if it had been Lionel . Compared with DCS, TMCC and Legacy have been engineering marvels.


"With Adrian's extensive help (Thanks again, Adrian), we've landed on the beefier TVS as shown in his original post of the back of the TIU with the four yellow sketched diodes. His daughter card design is probably the "silver bullet" fix but isn't exactly practical in a production sense. That's why we are going with the four larger TVS's attached to the signal transformer on the back of the TIU PCB.

All new Rev L TIU's produced going forward will contain these TVS's. In the field we have a Service Bulletin that was released today, in fact, that outlines removing the old mod (wimpy diodes) with the larger ones. While Adrian noted that there were still occasional failures, it's a balance of fixing it without re-designing and laying out a new PCB vs. applying a solution that gets most TIU's serviceable long-term.

From MTH's Service perspective, we will be adding this mod to all TIU's that arrive in for service with blown xmit chips or any condition that would indicate such. Additionally, this mod can be applied to any Rev TIU you have in your inventory. 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 those of you who are ASC's you will have this service bulletin. I've also shared it with Barry Broskowitz so he can post it on this forum to let those that have the ability apply it to their TIU's. MTH isn't carrying the component at this time so you can get it from Digi-Key per the bulletin.

NOTE - If you are NOT an ASC and you attempt this mod and damage a TIU that is under warranty, it will void the warranty.

Thanks,

MTH"

Words escape me!

George

Reads like a discussion page for electrical engineers and techs who are into hobby electronics and have a ton of cash to blow. The box should read "not for the average consumer"

jlong wrote:Reads like a discussion page for electrical engineers and techs who are into hobby electronics and have a ton of cash to blow. The box should read "not for the average consumer"

Certainly true. Not really the point. The susceptibility of the TIU to, especially, shorts caused by derailments has been a serious problem. Our club (AGHR in San Pedro) has had to buy new TIU's every year. We are blessed to have as a member a genuine electronic genius (professor at UCLA, contractor to JPL) who tackled the TIU issue and rebuilt all the club's units. They are now trouble-free. Adrian offered his design fixes to MTH gratis (!) and is currently rebuilding the TIU's for the San Diego 3-rail club.

rex desilets wrote: The susceptibility of the TIU to, especially, shorts caused by derailments has been a serious problem. Our club (AGHR in San Pedro) has had to buy new TIU's every year. We are blessed to have as a member a genuine electronic genius (professor at UCLA, contractor to JPL) who tackled the TIU issue and rebuilt all the club's units. They are now trouble-free. Adrian offered his design fixes to MTH gratis (!) and is currently rebuilding the TIU's for the San Diego 3-rail club.

You are blessed to have someone like Dr. Tang. That DCS required the services of someone like him just to operate quasi-reliably is disgraceful. If someone puts a product out there for public consumption, it needs to work reliably. And for the past 16 years all we've been told by certain bigots is that "DCS is simple", in the face of significant data to the contrary.

MTH should pay the man handsomely. He's saving their bacon.

George

"And for the past 16 years all we've been told by certain bigots is that "DCS is simple", in the face of significant data to the contrary."

And that it is reliable, which clearly isn't the case. And one particular poster recently who attacks anyone who criticizes MTH about anything (GGG), and who claims it's only a problem on giant layouts. Wrong. George and I, reasonably technically capable individuals, can vouch that it can be problematic on a loop of track .

No one's saying that TMCC and Legacy are foolproof on big layouts. Tweaks can be necessary, but they are pretty much bulletproof on a few loops of track. Cannot say that about DCS. Serious problem in this hobby with "true believers" whose own loyalties have them on the offensive against anyone who has a problem with their "faith." Unfortunately for MTH, Dr. Tang cannot save their bacon, because it already is overcooked in the marketplace. Fortunately for MTH, most people still operate in conventional mode, where PS3 is not nearly as quirky and unreliable.

Neil (and anyone else for that matter), do you have any statistics on how many people run conventional vs. command? I can't recall seeing any.

George

Neil (and anyone else for that matter), do you have any statistics on how many people run conventional vs. command? I can't recall seeing any.

It's kind of complicated. There are people that are using command control components to run conventional trains and now you have LionChief and DCS's "Lite" version which are in between conventional and full blown command control. Sales figures are not that useful as DCS can use multiple TIU's and all of them support multiple remotes.

chuck wrote:

Neil (and anyone else for that matter), do you have any statistics on how many people run conventional vs. command? I can't recall seeing any.

It's kind of complicated. There are people that are using command control components to run conventional trains and now you have LionChief and DCS's "Lite" version which are in between conventional and full blown command control. Sales figures are not that useful as DCS can use multiple TIU's and all of them support multiple remotes.

Chuck, I agree that it is a bit complicated. Maybe we should phrase the question this way:

How many model railroads can operate in command control (Legacy, TMCC, LCS, DCS, DCS-Lite, DCC) vs conventional only? I would stipulate that the numbers only include model railroads that have installed command control, not sales.

I think that's a bit more rigorous.

George

I vaguely recall estimates that 70-80% of hobbyists still use conventional only, but that was many years ago and I don't remember the source. Somehow I think it was CTT. Wouldn't surprise me if the number is that much is even much higher. I would not count the Lionchief set buyers in conventional, but they correspond to the non-DCS, non-Legacy part of the population which is command in principle but conventional in outlook .

There is, to me, an amazing post by Gunrunner John on this topic:

https://ogrforum.ogaugerr.com/topic/wea ... 0351731948

This is on page 6 of the thread near the bottom. For convenience, I've reproduced it here.

I thought it was time to check out one of my TIU's, so I pulled one out of the box, it's a couple year old Rev. L.

HOLY COW! Even though this is barely used, the signal amplitudes are all over the map! Suddenly, it makes sense that we're seeing all sorts of issues with TIU signals. Hard to believe they came from the factory like this, three of the four channels have much lower signal output. I was using this one for a couple of years, but it didn't really get a lot of actual running time for my carpet central.

Honestly? My reaction is pure shock (not at Gunrunner John, but at the content).

Quality Control, where art thou?

George

G3750 wrote:Quality Control, where art thou?

It's on delivery from Godot Trucking.

Neil wrote:I vaguely recall estimates that 70-80% of hobbyists still use conventional only, but that was many years ago and I don't remember the source. Somehow I think it was CTT. Wouldn't surprise me if the number is that much is even much higher. I would not count the Lionchief set buyers in conventional, but they correspond to the non-DCS, non-Legacy part of the population which is command in principle but conventional in outlook .

As Chuck pointed out, the issue is a bit more complicated than it appears on the surface.

Panhandle 2.0 will have a separate loop of track (the C & P River Route) that will be capable of running conventionally. I will have a TPC there which I can switch to Conventional Mode. The operator will be able to control a conventional locomotive using a CAB-1 remote as a throttle. That's a nod to the grandkids and the use of my postwar conventional engines.

Regarding the global market-space for command control vs conventional, I must be a total outlier. I can't see myself running conventional on the new Panhandle. Without the above exception for the kids, I would be 100% command control. The Panhandle has no control panel; switches are activated by push buttons on the fascia or via CAB-1. The only other example of conventional running is the loop around the Christmas tree.

George