Changing Intellibox firmware

The Uhlenbrock Intellibox is a groundbreaking device that came out in the 1990s. Not only does it support three different track protocols (Motorola, DCC, Selectrix) at the same time, it also supports LocoNet and the IC2 bus, s88 sensor input and Märklin boosters. It provided two speed controllers too.

It was also upgradable, so when Uhlenbrock made improvements we could load updated firmware.

When I got my Intellibox it had version 1.203 installed. I found it incredibly stable and bug free. I read about updates over the years but never felt compelled to make any changes, since all the updates did not affect how I used my Intellibox. 

Recently I managed to short my Intellibox and I substituted another one I had obtained a few years ago in case of such a situation. This second device was running version 1.55 which is the latest version that was available for free. I was having some problems and I was not sure if the problems I was seeing were due to the newer version. I therefore decided to see if I could downgrade it to 1.203 to answer that question.

I had saved some of the update programs over the years but have never used any of them. The older update programs required us to create a bootable floppy disk, which would start the computer up in DOS, precluding anything else from running in the background. This is because the firmware update could not be interrupted in any way or the update would fail. I found one old PC with a floppy drive, but it does not have a serial port, so I could not use that to load the firmware.

Later, Uhlenbrock also released a CD image that could be burned onto a bootable CD. This CD created a RAM drive and copied the 1.55 update file into the RAM drive. This ensures that the program could read the file without any interruptions. 

I tried to modify the ISO image file to add the older firmware files and I made numerous CDs but the files copied to RAM only included the 1_55.IB file, never the additional files I was trying to add. Once booted, I was also not able to switch to another CD to access and copy additional files. So I eventually gave up trying to make a bootable CD.

I had also downloaded a more up to date Windows program from the Uhlenbrock site that is used to update to version 2.0 called IBUpgrade. I installed that and selected the 1_203.IB firmware file but it declared that to be an invalid file.

I wrote to Uhlenbrock asking if they could perhaps create a CD image with all the free versions so we could select the firmware version. After numerous mails they directed me to use their windows update program at https://uhlenbrock.de/de_DE/service/download/software/I0011930-001.htm and they also sent the firmware files I was interested in.

Of course I said I had already tried that and at that stage they said, I am using IBUpgrade and I should be using IBUpdate. See the difference?   They have two programs that look identical, and only differ from each other in names that are synonyms of each other! Update vs. Upgrade.

So, I uninstalled IBUpgrade and downloaded and installed IBUpdate. I was able to select the 1_203.IB firmware file and start the process.

Finally I could load different firmware versions and test to see if the older version made any difference.

It did not make any difference. As soon as I connect a Märklin booster and switch track power on, the s88 bus gets filled with garbage data. You can read about that saga here.

An electrical disaster (A geek tragedy)

This is how I managed to destroy an Intellibox (IB) and two boosters at once. Well OK, it is still somewhat of a mystery, but here is the story...

I have 4 power districts on my layout, powered by my Intellibox and three boosters.

Everything shares a common ground, including other small devices around the layout that run on 16VAC or 5VDC or 12VDC. I run using mixed Motorola and DCC protocols.

One of those devices is a turntable which takes 16VAC and rectifies that to drive the motor using DC. There are six contacts that go to the turntable:

• Track center rail
• Track running rail #1
• Track running rail #2
• Motor positive
• Motor negative
• Solenoid

The track connections are digital, i.e. a square wave AC signal.

The turntable motor connections are all about 20V DC 

I was trying to resolve a contact problem and I was measuring the voltages on the contacts shown above and I may have measured the voltage between the turntable power contacts and one of the rail contacts. A voltmeter should not be able to conduct much current between its probes.

The next thing I noticed was that the IB screen was dark. It had blown the 3A fuse on its power supply line. I replaced the fuse. The Intellibox complained of a short and then presence of an external voltage. After that it would no longer power on. I attempted a repair of the Intellibox.

After placing another Intellibox (running version 1.55) in service, I found that the sensor bus was reporting nonsense, and the last booster in the chain of boosters was making trains in its section move, and lights flicker. I traced the problem to the first and second Märklin 6015 boosters! Once I removed them, trains in the last power district worked normally and there were no spurious sensor reports.

I obtained a used Märklin 6017 booster and tried that, and I got the same result. No matter which of the three Märklin boosters I connect, I get s88 interference and trains start running even when the IB is in STOP mode. It is as if they are putting analog current out.

I have an old Modellbahn Ott 100W booster and I connected that in the same place as the Märklin boosters and it does not exhibit any problems.

Update 2024-01-05

I obtained another Märklin booster - a 6015.

This one does not send bad output to the tracks, but when rail power is on, I get the junk s88 readings. This is now making me suspect that there is something wrong with the s88 bus of the Intellibox. Track output seems to be leaking into the s88bus, but only in the presence of a Märklin booster. I will be retesting to see if I can locate a defective s88 module, however I believe this is not the case because with the Ott and Power 3 boosters, they all work fine.

Special Option 901 = 3. This controls the asymmetry of the digital signal, and a value of 3 is recommended when using 6015 and 6017 boosters.

Here is a summary of the behavior of each of the 6 boosters I have:

A = Märklin 6015

B = Märklin 6015

C = Power 3

D = Modellbahn Ott 100W booster

E = Märklin 6017

F = Märklin 6015

IB 1.203   IB -> A -> B -> C. Everything was OK

IB 1.55   IB -> A -> B -> C. STOP: flickering and trains moving  GO: s88 garbage

IB 1.55   IB -> A.  STOP: flickering and trains moving  GO: s88 garbage

IB 1.55   IB -> B.  STOP: flickering and trains moving  GO: s88 garbage

IB 1.55   IB -> C.  All OK

IB 1.55   IB -> D.  All OK (See update 2024-01-11)

IB 1.55   IB -> D -> C.   All OK (See update 2024-01-11)

IB 1.55   IB -> E. STOP: flickering and trains moving  GO: s88 garbage

IB 1.55   IB -> F.  STOP: OK  GO: s88 garbage

Update 2024-01-06

Sometimes, when one of the Märklin boosters is connected, I can select a loco address if the track power is off. If the track power is on, then an attempt to select any loco is met with the message "Error" in the loco address area. 

(Note the irony in that the error message has German style hyphenation on an English word! I noticed this error is not in the IB control though.)

I wrote to Uhlenbrock support and described this problem and they replied saying this error occurs if the Loconet is corrupted and that the Intellibox is in need of repair. (See below on an update on this.)

Update 2024-01-11

We have found that if we disconnect the connection (red) to the rails, from a Märklin 6015 booster the corruption of the s88 bus stops, and returns as soon as it is connected again.

My son and I spent a day disconnecting everything from the red feed in one of the power districts (all trains and K83 / k84 modules) and it makes no difference. To me this now suggests that there is electromagnetic interference occurring between the bundles of s88 sensor wires and the track power lines. The s88 bundles are all shielded cables and have never given any problems in 20 years.

We also found that if we waited long enough, the Modellbahn Ott booster does indeed also precipitate false s88 changes, but way fewer than with the working 6015 booster we have.

If we connect the Power 3 Booster to any of the 4 power districts, no corruption of the s88 bus occurs.

I now believe that the IB is not defective in terms of a bad s88 bus port or booster output. I also think the corruption of the Loconet is because the IB gets overwhelmed by the number of s88 changes. This explains why the loconet goes haywire when track power is on, as that is when the false s88 messages come flooding in.

So despite the IB working perfectly with Märklin boosters for decades, a 6015 no longer works with this IB. The only difference I know of is that this IB is running a newer version of the firmware (1.55). If version 1.55 really did not work with Märklin boosters I am sure that this would be a well known problem though.

Uhlenbrock now maintain that the Märklin boosters do not work well with DCC signals. This is strange because they have worked fine in the past and there is a special option (901) which specifically adjusts the symmetry of the digital signal to support them. Uhlenbrock recommend using Power 3, Power 4 or Power 40 boosters instead.

The difference in behavior of my original 6015 boosters (A & B) plus the 6017 (E) I bought on eBay compared to the 6015 (F) I bought on eBay, make me believe that both my original boosters died and the 6017 I bought, also suffered a similar fate before. That booster (E) has now been returned.

I am now looking for Power 3, Power 4 or Power 40 boosters.

I am also going to test with sending only motorola packets to rule out DCC as being the issue, and I am also going to get an old computer going that will allow me to load an older firmware version to see if that resolves the problem.

Update 2024-01-14 

I got rid of all DCC signals by setting the following special options:

SO 6 = 1

SO 12 = 0

SO 22 = 6

SO 25 = 2

SO 901= 1

SO 904 = 28

SO 907 = 1

SO 909 = 198

SO 931 = 1

As expected, the Märklin booster still causes corruption on the s88 bus.

Update 2024-01-28

I managed to downgrade the firmware of the IB to 1.203 - which is what my original IB was running.

It behaves the same. So it is not the firmware version.

I have some second hand Power 3 boosters on their way from Germany. I hope they resolve the problem.

Resolution

After replacing the Märklin boosters with Uhlenbrock Power 3 boosters and adding a fourth booster instead of using the IB output, everything is working again.  The nature of the failure is still a mystery.

Repairing the output stage of the Intellibox

After 23 years of use, I managed to burn out my Intellibox!

I think it happened when I was measuring the voltages of my turntable and I must have touched the track center rail contact with one of the probes. The 3A quick blow fuse on the power supply line to the Intellibox blew. I replaced that and then the Intellibox (IB) complained about a short. I disconnected things and tried a few times and then it said "Attention Extern. voltage".

I disconnected everything from the IB and all it would display was the same error.

This is how I went about repairing it. Though unsuccessful, the method of doing the work may be useful to others.

I recalled online discussions from years back that one had to drill out the plugs on the underside in order to open the IB case. I did so (but used a drill bit somewhat oversized) and opened it up. Nothing  could be seen to be destroyed, but the obvious candidates are the two power output transistors. These were BD535 and BD536.

I could not find replacements online and I asked in the IBX online forum for suggestions and also emailed Uhlenbrock support. As usual, J.J. McVeigh was extremely helpful and said that he had successfully replaced the transistors with NTE152 and NTE153, and that their 4 Amp rating would not be a problem since the IB output is limited to 3A. I ordered some online and started removing the old transistors. Uhlenbrock replied that they replace these with BD911 and BD912 (Also not readily available in the USA.)

This comprises cutting their legs off and unscrewing them from the heat sink:

and pulling the pins out the underside while melting the solder from the top:

To get the solder out of the holes I used some flux paste and some copper solder wick

I then cleaned up the flux with some alcohol.

One of the transistors tested to be bad, so I was confident I was replacing the correct items.

The new components arrived:

and it was pretty easy to solder install them. After careful cleaning, I used the existing insulation pads, screwed the new transistors in place and then soldered the legs in. The effect of the heat sink meant that the middle legs called for a 700°F soldering iron.

I reassembled all the parts and tried it out, and sadly I still get the same error. Something else in addition to the power outputs appears to be damaged. I may need to ship the IB back to Germany for repair at Uhlenbrock.

Intellibox turnout speeds and special option 13

XTrnt response codes

I turned on the logging I have in my software and noticed that I was getting a lot of responses from my Intellibox warning me that the turnout buffer was 75% full, and also numerous rejections of turnout commands when the buffer was completely full. When this happens, my software throws the failed commands back into its own command queue so that it eventually gets accepted, so once the Intellibox buffer fills up, I get many rejections until the buffer is no longer full.

Added Special Options descriptions to SO list of Intellibox

Some years back I added the ability to retrieve, and log, every Special Option (SO) value of the connected Intellibox. The log can be saved as a text file. This provided a nice way to keep track of what they are.

Philosophy of digital train control

Background

Controlling model trains with a computer has been around since 1986 when Märklin introduced their digital system. Since then there have been numerous improvements and a wealth of new digital items and products. Some things have, however, remained the same. All digital systems consist of decoders (usually in locomotives) and they are all controlled by computers, even if the computer does not look like a computer. The Märklin digital controllers, the Intellibox, ECoS and Viessmann controllers are all computers. Some of these controllers also allow computer input from general purpose computers such as PCs and Macintosh machines and allow greater flexibility and power in controlling a train layout digitally.

Wiring the Intellibox plug

Attaching decent large diameter wires to the Intellibox is not easy. I would say it is the biggest problem with the Intellibox so I decided to make a better set of connections for the Intellibox.

Note that one can use two ground wires (black above) connected for the power input and mainline digital output. (Keep programming track wires separate.)