RTR-MB1

Technical Information

RTR-MB1
Device Information Manufacturer Train Control Systems Type Motherboard SKU 1615 Release Date 03-July-2024 (Rev5) Retail Price $59.95 Lighting Outputs 8 Bulb Outputs Up to 8 (Selective) LED Outputs Up to 8 (Selective) Current Rating >3A Output Rating >100mA (Each) Keep Alive® On-Board

The RTR-MB1 from TCS is an 8-function 21-pin decoder motherboard with integrated Keep Alive® on-board. The RTR-MB1 was designed specifically to fit Athearn Ready to Roll and “Blue Box” diesel locomotives in HO-scale. This motherboard features an on-board regulated 1.5V power supply for incandescent “rice” bulbs, and can also be used with LEDs thanks to on-board resistors. Configuration is done via solder jumpers, which is required in order for the RTR-MB1 to function. See the Lighting Wiring Instructions section below for detailed instructions.

The RTR-MB1 has been designed to meet NMRA standards, and is compatible with any NMRA-compliant 21-pin decoder with up to 8 lighting outputs, such as TCS’ WOW121 or EU821 decoders (sold separately). All of TCS' motherboards, including this one, are available for purchase with "high pins" which are compatible with 21-pin decoders from other manufacturers. Since TCS designs decoders with a lower profile, they can be used with a "low profile" pin header. The TCS decoder and motherboard with low profile pins will often fit into installations which would otherwise be impossible due to height clearances.

Pin Headers

Low Profile (TCS Compatible)	High Profile (Non-TCS Compatible)
Click to Enlarge	Click to Enlarge

Wiring Diagram

Shown below is the latest wiring diagram for the RTR-MB1. This diagram depicts the "Revision 5" version of the RTR-MB1, which is the current production version.

Click to Enlarge

Lighting Wiring Instructions

Information in this section pertains specifically to the revision of the RTR-MB1 released in 2024. The RTR-MB1 was redesigned in July of 2024 to have more feature options for lighting outputs. These options are now configurable through the use of "solder bridge" jumpers located on the top side of the motherboard.

Wiring Instructions for 1.5V Incandescent Bulbs

Perform these steps below to configure the motherboard for 1.5V lighting:

1. Solder bridge “1.5V” to “V+” as shown below:
2. Connect one wire from each bulb to “V+” OR “1.5V”
3. To use 1.5V bulbs for headlights, you must bridge the corresponding jumper(s) for F0F and F0R shown in the diagram below:
4. To finish wiring the headlights, connect the second wire to the F0F and F0R pads shown in the wiring diagram.
5. To add more 1.5V bulbs, connect one wire to either "V+" pad or the "1.5V" pad, then connect the second wire from each bulb to the numbered pads directly next to the “BULBS” label.

NOTE: It is possible to use both incandescent bulbs and LEDs simultaneously. To do so: Wire any incandescent bulbs to the "BULBS →" pads and the correct supply voltage pad (1.5V or 12V). Wire the LED Anode (+) to the "12V" pad, then wire the LED Cathode (-) to any of the numbered "LEDs →" pads

Wiring Instructions for 12V Incandescent Bulbs

Perform these steps below to configure the motherboard for 1.5V lighting:

1. Solder bridge “12V” to “V+” as shown below:
2. Connect one wire from each bulb to “V+” OR “12V”
3. To use 12V bulbs for headlights, you must bridge the corresponding jumper(s) for F0F and F0R shown in the diagram below:
4. For Headlights: Connect the second wire to the F0F and F0R pads shown in the wiring diagram.
5. To add more 12V bulbs, connect one wire to either "V+" pad or the "12V" pad, then connect the second wire from each bulb to the numbered pads directly next to the “BULBS” label.

NOTE: It is possible to use both incandescent bulbs and LEDs simultaneously. To do so: Wire any incandescent bulbs to the "BULBS →" pads and the correct supply voltage pad (1.5V or 12V). Wire the LED Anode (+) to either "V+" pad or the "12V" pad, then wire the LED Cathode (-) to any of the numbered "LEDs →" pads

Wiring Instructions for LED Lights

Perform these steps below to configure the motherboard for LED lighting:

1. Solder bridge “12V” to “V+” as shown below: No additional jumper configuration is required when using LEDs for both headlights.
2. Connect the Anode (+) wire from the headlight(s) to either “V+” pad OR the “12V” pad
3. Connect the Cathode (-) wire to the F0F and F0R pads shown in the wiring diagram.
4. To add more 12V bulbs, connect one wire to either "V+" pad or the "12V" pad, then connect the second wire from each bulb to the numbered pads directly next to the “BULBS” label.

NOTE: It is possible to use both incandescent bulbs and LEDs simultaneously. To do so: Wire any incandescent bulbs to the "BULBS →" pads and the correct supply voltage pad (1.5V or 12V) Wire the LED Anode (+) to either "V+" pad or the "12V" pad, then wire the LED Cathode (-) to any of the numbered "LEDs →" pads

All Jumper Configurations

From the factory, none of the option jumpers will be selected. As such, there is no voltage present on the "V+" pads on the front and rear of the board. Additionally, the factory configuration sets up the F0F and F0R outputs for LED operation. Depending on how you intend to wire your locomotive, you must bridge the correct jumpers with solder. In total, there are four Jumpers available:

1. Supply Selection - 1.5V
2. Supply Selection - 12V
3. F0F Bulb/LED Selection
4. F0R Bulb/LED Selection

Leaving the F0F and F0R jumpers disconnected will set up the F0F and F0R pads for LED operation. bridging these jumpers will bypass the on-board resistors and allow you to use incandescent bulbs.

Listed below are all of the valid configuration options for the RTR-MB1. Note that it is now possible to use both incandescent bulbs and LEDs simultaneously in the same installation. It is also no longer necessary to add external resistors to use LED headlights.

All Valid Jumper Configurations

1.5V Selection for V+	12V Selection for V+
1.5V Lighting - 1.5V Bulb Headlights (FWD & REV)	12V Lighting - 12V Bulb Headlights (FWD & REV)
1.5V Lighting - 1.5V Bulb Forward Headlight, LED Reverse Light	12V Lighting - 12V Bulb Forward Headlight, LED Reverse Light
1.5V Lighting - LED Forward Headlight, 1.5V Bulb Reverse Light	12V Lighting - LED Forward Headlight, 12V Bulb Reverse Light
	12V Lighting - LED Headlights (FWD & REV)

Failing to select a supply voltage will result in an open circuit to "V+" and no lights wired to the "V+" pads will operate since no voltage is present.

Invalid Configuration

Invalid Configuration (No V+ Voltage Selected)

Previous Revision Information

None Available