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LocoFi 2 &3 with Cytron MD13S H-bridge

Has anyone installed a LocoFi modified DULLHA or DULLHB system with a Cytron MD13S H-bridge in a locomotive and have it operational?

Are you using the latest version of the LocoFi software, 2.3 ?

Did you encounter any issues with the installation in the locomotive, diesel or steam?

Did you experience the ERR light illuminating on the Cytron MD13S board and what was the cause of the ERR?

Did you encounter any issues with the cellphone communicating with the LocoFi system such as with the horn, bell, throttle, lights forward and reverse, startup and shut down, emergency stop operating properly?

What bridge rectifier did you use?

Did wire colors coming from modified LocoFi board cause you any concern when connecting it to the harness/plug that comes with the Cytron MD13S H-bridge?

Are modified LocoFi system tested prior to shipment connected to a Cytron MD13S and a DC motor?

Reason for asking these questions is to collect any past experinces you may have had performing this installation and operation of your locomotive.

All comment appreciated. Thank you !!!!

12 comments

12 Comments

John Holdos

Aug 18, 2022

Best Answer

Got back into fitting a modified LocoFi system with an H-bridge into a brass 2 rail O gauge steam locomotive and can report we tried the locomotive on a large model railroad club layout and the system performed great. This installation was done primarly to see if a LocoFi system would work in an old brass 2 rail O scale steam locomotive having a high amp draw open frame motor.

Some of the things learned are that a "keep alive" system is necessary to compensate for power interuptions when operating on a club layout., mainly in turnouts.

Since a steam sound package is not avilable the diesel sound package was used as a baseline and found that using a 3 W 4 Ohm baffeled speaker did not produce an adequate sound level. Between the noise of the open frame motor and drive train of the locomotive it drowned out the engine sound coming from the speaker. Horn sound level was marginal. Bell sound level was OK.

The club layout operates on clean 12 VDC and it apperared it was not adequate for this old style locomotive. 18 VDC would have been prefered and the locomotive would have performed better. Throttle was at 3/4 position to get the locomotive to move and at full throttle at 34 mph track speed with no cars attached to the locomotive. Overall the LocoFi system performed perfectly and was able to establish and maintain a local area network with the modified Locofi system and H-bridge located in the brass tender. Previous problem with not being able to establish a local area network in this posting was a fault done by me in the use of the phone.

The next phase is to finish the installation of modified LocoFi system with an H-bridge in a high amp draw, 3 rail, O scale, twin can motor diesel locomotive. After observing how the steam locomotive performed, no problems are antisapated and the diesel sound package with a 3 W 4 Ohm speaker should provide an adequate sound level for club use. The need for a "keep alive" system will probably also be needed for this installation and club use.

Admin

Aug 18, 2022

Replying to

Hello John,

Thank you for the follow up post. Much appreciated. We're glad to hear that all of the original issues have been resolved.

>Some of the things learned are that a "keep alive" system is necessary to compensate for power interuptions when operating on a club layout., mainly in turnouts.

"Keep alive" is certainly an option here. However, we would suggest you take a look at 'FAQ -> Troubleshooting -> 01'. It would be great to review the following couple of things:

Are all wheels (on both sides) picking up power? Try the "continuity" test with your multimeter between each wheel of either side.
Does the locomotive tend to tilt on one side while going over a turnout such that there is a temporary loss of connection of ALL the wheels with the rails? The locomotive will keep going due to its momentum and immediately get power again soon enough to completely disconnect (it may actually even disconnect at slow speeds). Running at slow speed will be a good experiment to observe this. The wheels should be "free" enough that if one set "dips" in the turnout, the others keep the power going.

>...found that using a 3 W 4 Ohm baffeled speaker did not produce an adequate sound level.

Try getting a larger speaker with more "sensitivity". More importantly, make sure the baffle (speaker box) is good.

>18 VDC would have been prefered...

Another advantage of using LocoFi™. Run at a variety of voltages!

Again, thank you so much for the follow up writeup. It clears up things a lot! Eagerly looking forward to the 3-rail test!

Best regards,

LocoFi™ Team

John Holdos

Jul 22, 2022

Having a problem with android cellphone, BLU STUDIO X8 HD 8.1 edition, and SAMSUNG android tablet GALEXY TAB S5e, connecting with O scale, 2 rail and 3 rail locomotives when wifi network is not available. When wifi network is available LocoFi system operates properly. DULLHA and DULLHA systems, modified by LocoFi for high amp motor use and a Cytron MD13S H-bridge plus a 10 Amp bridge rectifier are installed in both locomotives. If anyone has information why this connection cannot be made can you submit your thoughts and a solution. Thanks in advance an await to hear from you.

John Holdos

Jul 01, 2022

The bridge rectifier used in the 3 rail conversion is 4 amp because the twin motors draw slightly over 2 amps at start-up plus with the Cytron MD13S H-bridge installed everything is operating A-OK.

The 2 rail conversion started with a 4 amp bridge rectifier and experienced problems. Can't say if the bridge rectifier was the sole issue or a contributing issue because clean DC power was not used.

Rembering past research on the amount of stall amps various O scale locomotives drew, 1+ amps up to 6.75 amps, plus not knowing exactly what my locomotve's stall amp drew, an 8 amp bridge rectifer and a MD13S H-bridge were installed along with clean 12 VDC power and everything operated A-OK. 4, 6 or 8 amp should work, it depends on the amp draw of your locomotive's motor(s).

THANK YOU !!! LocoFi and Cytron Technologies for your support by providing technical advice throughout the conversions.

Admin

Jul 04, 2022

Replying to

Can't say if the bridge rectifier was the sole issue or a contributing issue because clean DC power was not used.

It appears that not having clean DC power was the major issue. A bridge rectifier would usually blow up if trying to draw more amps than it's rated for.

THANK YOU !!! LocoFi and Cytron Technologies for your support by providing technical advice throughout the conversions.

You're very welcome, We're glad to hear that things are working well now.

John Holdos

Jul 01, 2022

A modified LocoFi system has been installed in an O scale, 2-rail and a 3-rail locomotive.

Early problems centered around having clean DC power and bridge rectifier size with the MD13S H-bridge.

Using a test stand has shown everything is now working properly on both conversions. Testing will now progress to a large club layout and will center primarily on communications between the Android phone or table and the locomotives. Past experience has showed that a router was required when operating an O scale locomotive, outfitted with LocoFi, on a large club layout. With the latest LocoFi software update, loss of signal and emergency stop, testing +is going to make the evaluation much easier.

One major concern with the 2-rail conversion is that the LocoFi system is located in the locomotive's brass tender. The tender has no openings for the control signals to enter. Modifications may have to be made to the tender's body or an external antenna may be required. Future tests results will be posted ASAP

Admin

Jul 04, 2022

Replying to

One major concern with the 2-rail conversion is that the LocoFi system is located in the locomotive's brass tender.

Great to hear that everything is working as expected. Please keep us posted about your tests with respect to installation in the brass tender.

Admin

Jun 22, 2022

TYCO 899 isn't putting out "clean" DC which maybe an issue in getting things to work. For higher amps, something similar to https://www.amazon.com/ALITOVE-Universal-Regulated-Switching-Transformer/dp/B06XJVYDDW?th=1 should provide plenty power for large scale layouts. It's clean regulated DC and doesn't cost a fortune. In fact, it is much cheaper than you would pay to get a used and bulky TYCO off of eBay.

You have some great successful experience with running battery powered ("deadrail") locos and battery gets you the best possible "clean" DC. If switching to track power, please use regulated "clean" DC or use a "filter" capacitor at the output of your "pulsed" DC power supply. See FAQ -> Troubleshooting -> 02 for more details.

John Holdos

Jun 21, 2022

Best I can get is 12 VDC and 1 Amp output. from the TYCO unit. Can't tell you more than that at this time.

John Holdos

Jun 21, 2022

What kind of power supply?

i am using a TYCO Model 899 to power a 36" long test track. The locomotive is powered via the tender and the locomotive is suspended above the tracks so that there in no resistance on the drive wheels and speed and be run up with having a problem with a short test track.

What kind of bridge rectifier?

i have a Vishay Bridge rectifier 4 Amp 50 volt 200 Am. Will upgrade that to 6 Amp. See no problem using the 4 Amp bridge rectifier since the locomotive motor is not being put under load and only in the early stages of the locomotive modification. Also see that bridge rectifier is only required for change in polarity of track power to protect the H-bridge.

As to your wiring diagram?

I am refering to the one that LocoFi has. It is a colored schematic with a photo of the Cytron MD13S in it. Only issue I found using that illustration was that the white wire coming from the modified LocFi board to the H-bridge is gray colored on the schematic. You have to be careful when using the Cytron harness that you do not color match wires when splicing and only refer to designated terminals to insure that you haved wired the two components together correctly.

Admin

Jun 21, 2022

Replying to

Thank you for that information. One more question.

Does the "TYCO Model 899" output "clean" DC? What's the output voltage and max current?

The colors in the wiring diagram are for illustrative purposes only. The key thing to remember is to interface DIR, PWM and GND correctly. The corresponding colors of the output wires are mentioned in the NOTES section of each invoice. The current color coding is subject to change for future modifications. This is something new and we are not setting standards here (yet). However, we will take a look at revising the wiring diagrams and coming up with a more consistent color coding. Thank you.

Admin

Jun 21, 2022

Hello John,

Thank you for being one of the early adopters of customizations that allow for driving high current motors. We're sorry to hear about the issues with MD13S.

We can help answering some of the questions.

>Are modified LocoFi system tested prior to shipment connected to a Cytron MD13S and a DC motor?

Yes. We have a testbed with MD13S driving a motor. For each mod we do, we test the whole system by connecting the newly exposed DIR and PWM outputs to the testbed and making sure not only the motor but everything including the lights and sounds work. Please note that MD13S is only one example of an H-bridge. It is impossible to test with each type of H-bridge out there. In case of ERR light on the MD13S H-bridge, it's best to contact Cytron and find out what might cause the ERR light to come on (we did not find any documentation related to that in any of their manuals except that "it will illuminate when fault detected in on board MOSFET driver").

>Did wire colors coming from modified LocoFi board cause you any concern when connecting it to the harness/plug that comes with the Cytron MD13S H-bridge?

It appears that the color codes of the harness wiring that comes with MD13S is opposite to that of what LocoFi™ uses to expose the outputs. If you were to use any other H-bridge, it may come with other color codes or in fact may not come with any harness at all. Please refer to the important NOTES provided in the invoice that explains how the wiring needs to be done with any H-bridge.

For issues with sounds it is possible that they might have been corrupted. To restore the sounds, please follow the two step process below:

1. Take the microSD card out (see Replacing microSD card) and format it using the software available at https://www.sdcard.org/downloads/formatter/. Please use the "Overwrite format" option.

2. Download the "Generic Diesel 01" from the Sounds section on the Resources page of our website. There's notes there on how to copy them onto the microSD. That should get you the sounds back.

It would help to know:

1. What kind of power supply are you using? Our recommendation is to use a "clean" DC power supply rated for stall motor current + 1A DULLHB + at least couple of amps buffer.

2. What kind of bridge rectifier are you using? Again, our recommendation is to use something rated for higher than the stall motor current.

3. Your wiring diagram?

Inputs from other high current installations using mods to the LocoFi™ modules are highly appreciated. Please help John in anyway possible.

- LocoFi™ Team