I have just purchased a new Behringer FCB1010 pedal board. Why? First, it does quite a bit of what I plan to do with my Line 6 pedal board. Second, it’s cheap.
I know that this is an old design, that it has been around for years (at least since 2003), and that there are replacements available. But again, it has the switches that I need, and it does quite a bit all by itself. It’s well built and easy to fix.
Now, you don’t really own a gadget until you hack it. I know that too. So guess what? First thing I did was unscrew everything and start tinkering!
- Lower right: six pedals linked to switches on a board. Very similar to my Line 6 pedal board. Similar switches. Similar circuit. Instead of using a resistor ladder to code the switch signals, this board uses direct connection. This means that each switch and each LED is linked to a pin on the connector. There is a 14 pin connector there, so 12 pins for the switches and LEDs, a + voltage and a ground wire.
- Middle left: 2 expression pedal boards. These are very similar to the ones on the Line 6. A simple photo-transistor amplified signal linked to a gray-scale plastic insert moved by the pedal. The varying voltage is sent to an analog-to-digital converter on the main board.
- Middle right: Upper pedal board. Same as the lower one.
- Top right: Midi IN-OUT board. The IC (IC1: H11L1) on that board is a simple opto-isolator, required by the midi standard to prevent ground loops between equipment.
- Top right, just a bit left: Switch board: used to connect to switchable amplifiers.
- Top left: power connector, power switch and power transformer. Nothing special. I have not measured the power transformer’s output, but the presence of a 5 volt voltage regulator on the main board lets me believe that the voltage on the main board is 5 volts. Convenient. This is probably a 9 volt power supply.
- Top middle: The main board. A bunch of transistors, ICs, relays and miscellaneous parts.
The main board is kind of divided as follows:
- Left: Transistor and resistor arrays to drive the display digits segments.
- Middle: Integrated Circuits for
- IC 10,IC3,IC11: 74HC273D: D-Type octal flip flops. 2 are used to control the 7-segments LED digits and 1 is used to receive the pedal inputs.
- IC12: C0832C: 8 bit analog/digital converter to transform the pedal analog signal to digital
- IC2: T805: Voltage regulator, 5 Volts.
- IC7: TL7705ACD: Power supply supervisor. Ensures clean power to main chip.
- IC6: Atmel62- 24C16A: 2wire 16K EEPROM. Memory module. Usage unknown. Maybe a boot loader for the system.
- IC8: Philips P80C32SBAA: Micro-controller. This is the brain of the pedal board.
- IC4: 74HC04: Hex inverter. Various use throughout for logic signal inversion.
- IC5: 74HC130: Multiplexer. Driving logic (clocks and clear) for ICS 3, 10 & 11 (74HC273)
- IC9: 74HC373: D-Latch flip flops: Logic driver.
- IC14: M5M5256FP-85 (or SR32K8 on schematics): 32K X 8bit RAM.
- IC13: 27C256: 256K EEPROM. Of course, the biggest IC on the board is the firmware EEPROM on the right. Mine is version 2.501E, the last one available.
So, The main board is a micro-controller with some RAM, a firmware chip, some IC interface to drive the display, another IC to get inputs from the pedals. The main question: Can I replace this board with a home-brew Arduino board? You bet. Or “your” bet… I am confident that it can be done, but haven’t done it yet.
The project is to build the Arduino supported controller and make the code open source for all to share. There.