SC712 – RCBus Power Supply Module

SC712 is a power supply module for RCBus.



Nothing known


KitsWebsiteShips from
Stephen C CousinsTindieUK
PCBsWebsiteShips from
Stephen C CousinsTindieUK
Assembled and TestedWebsiteShips from
Not available
See parts list

Parts List

PCB1SC712, v1.0, PCB
C1 1Capacitor, electrolytic 100 µF
C20There is no C2
C3 and C42Capacitor, ceramic, 100 nF
C51Capacitor, ceramic, 1 nF
J11Socket, power, barrel, 2.1mm
J2 and J32Screw terminal, 2 way, 5mm pitch
JP1, P2, P33Header, male, 1 row x 2 pin, angled
or 8 pin strip with 2 pins removed
JP21Wire link (eg. resistor offcut), or
Header, male, 1 row x 3 pin, straight
Jumper2Jumper shunt
LED11LED, green, 3mm, angled
LED21LED, red, 3mm, angled
P11Header, male, 2 row x 40 pin, angled
P2 and P3see JP1
R1 and R22Resistor, 1k, 0.25W
R31Resistor, 100k, 0.25W
R41Resistor, 10k, 0.25W
R5 and R62Resistor, 4k7, 0.25W
SW11Switch, toggle, sub-miniature, SPDT
SW21Switch, tactile button, angled
Screw (for spacer)1Machine screw, 6mm, M3
Spacer1Spacer, 10mm, M3, nylon
U10There is no U1
U21DS1233-5+ supervisor
IC socket 14-pin
114-pin PDIP socket

Printed Circuit Board


This module conforms fully to the RCBus specification v1.0 and thus supports: RCBus-2014, RCBus-Z80, RCBus-68xx, RCBus-9995.

User Guide

This module provides a 5-volt supply to the backplane. Voltage input is between 5 volts (4.75 to 5.25 volts) D.C. at a maximum of 1 ampere. The input can be connected to either J1 (centre positive) or the screw terminal J2.

The 5-volt output is connected to the backplane and is also available at screw terminal J3 and header pins P3.

The system reset signal is generated at power up, upon pressing switch SW2, or with an external switch connected to P2. The power up reset is generated by the voltage supervisor U2. The supervisor will also hold the system in reset if the 5-volt supply drops below about 4.75 volts. In addition, the supervisor cleans up the reset signal generated with the reset button.

The system should only have one enabled voltage supervisor. If there is another one in the system, one of them needs to be disabled. The circuit on this module is likely to be the best one, so ideally keep this one enabled and disable any others. To enable the supervisor on this module, fit a jumper shunt to header pins JP1.

Input/output port functions
RCBus I/O Address ReadWrite
Jumper options
JP 1Enable the voltage supervisor
Only one supervisor should be enabled in a system so it may be necessary to disable (isolate) one of them
JP 2Select the polarity of the on/off switch, either UP for ON or DOWN for ON
J 1Barrel socket, power supply input, 5 volts D.C. centre positive, maximum current 1 ampere
J 2Screw terminal, power supply input, 5 volts D.C. centre positive, maximum current 1 ampere
J 3Screw terminal, 5-volt output, maximum current 1 ampere
P 1RCBus connector
P 2Header pins, optional external reset switch
P 3Header pins, 5-volt output, maximum current 1 ampere

Assembly Guide

Below is the suggested order of assembly. A general guide to assembling circuit boards can be found here.

  1. Resistors R1 to R6
    These can be fitted either way around
  2. Socket for U3
    Ensure the notch in the socket matches the marking on the PCB
  3. Header pins P1
  4. Capacitor C5
    This can be fitted either way around
  5. Capacitors C3 and C4
    These can be fitted either way around
  6. Capacitor C1
    This must be fitted the correct way around, as described here
  7. Switch SW1
  8. LED1 and LED2
    The angled LEDs in the kit only fit one way around, but standard LEDs need to have the short lead in the hole marked with a flat line, as described here
  9. Switch SW2
  10. Header pins JP1, P2 and P3
    P2, JP1 and P3 can be a single strip with two pins removed
  11. Barrel power socket J1
  12. Screw terminals J2 and J3
  13. Header pins JP2
  14. Voltage supervisor U2
    Carefully bend the legs to match the hole spacing on the PCB and ensure the orientation matches the markings on the PCB
  15. Fit IC’s U3 into its socket
    Ensure the notch in the IC matches the PCB and IC socket
  16. Fit jumper shunts to JP1 and JP2
    JP2 has two possible positions depending on your preference for the on/off switch polarity (ie. UP=ON or DOWN=ON)
  17. Fit the nylon spacer in the mounting hole


  • This product is designed for hobby use and is not suitable for industrial, commercial, or safety-critical applications.
  • The product contains small parts and is not suitable for young children.

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