Behringer FCB1010 – Alternate power source

Behringer FCB1010 – Alternate power source.

The Behringer FCB1010 has an internal power supply that is fairly easy to replace. There are a few options available:

• 1 Change the transformer if it is defective
• 2 Use a different power suplly
• 3 Use USB power

I will detail these options.

Open your FCB1010 by removing all the screws under your pedal board. Note that there are two screws holding the transformer and one screw for the grounding of the back plate. You don’t have to remove those. So there are 3 screws on each side of the back plate, a few more on the top and bottom of the plate, and six (6) screws in the middle attached to small brackets inside. 3 + 3 + 2 + 2 + 6 = 16 screws. Once opened, you should see the main board on the top. It should look like the picture above. But in that picture, I already unscrewed the main board.

You will need to unscrew the main board for options 2 and 3 only. To do this, remove the 3 small screws on the back of the FCB1010 that hold the board AND REMOVE the screw that holds the 7805 IC (picture below). That little part is attached to the FCB1010 frame because it can get fairly hot. The FCB1010 “frame” will dissipate that heat. Anyway, that screw is attached to a nut that is inside the FCB1010. You might have difficulty removing that nut without the proper tool (available in most “electronic” tool kits, but a pair of pliers might do the trick.

1- Change the transformer

The standard transformer in the FCB1010 is a 10 Volt AC unit. It should be easy to find from multiple sources. Actually, a 9 volt transformer will be OK for this circuit. In fact, 7 to 12 volts should do here. To replace it, make sure that you buy one of approximately the same size so that it fits inside the FCB1010. Once the new transformer is screwed to the back plate, you have to connect it to the main board. That’s the easy part! The two yellow wires should be attached to the output of your transformer. Since the transfo is AC by default, it doesn’t matter what output wire is connected to what yellow wire.

A bit of theory: The yellow wires are connected to a “full bridge rectifier” on the main board. The 7805 part that is screwed to the FCB1010 frame will transform the incoming voltage (about 7 to 12 volts) to exactly 5 volts. The parts with “c” followed but a number are Capacitors and are used to filter noise present in this part of the circuit. The parts with “d” followed by a number are Diodes and are used in this circuit to transform the AC voltage to DC.

If you want to use an existing power supply that you might have in stock from another piece of equipment, or if you want to use the standard 9 Volt supply from your guitar pedal board then it’s easy: you can keep the power supply outside of the FCB1010. Most power supplies have two wires: Ground and Power, or – and +. All you have to do is connect the – and + to the yellow wires of the main board. It doesn’t matter which yellow wire is connected to – or +. I suggest soldering. You could also plug off the power supply and screw a compatible socket in a hole on the FCB1010 for a clean, safe connection. I did that for a client.

Important Note: the external existing power supply should be 9 to 12 volts. It will probably be DC (most power supplies are DC). Since the yellow wires lead to a bridge rectifier, the DC voltage will find its way to the 7805 and convert to 5 volts. No problem.

2- Use an external 5 Volt power supply

We all have a ton of old 5 volts power supplies from all sorts of electronics that we purchased in the past. Phones, computer, games etc. If you want to use a 5 volts power supply, you’re in luck! The internal circuit of the FCB1010 works on 5 volts. That’s what the 7805 part does: convert the incoming 9 to 12 volts to exactly 5 volts. The only requirement is that you CAN NOT use the yellow wires to do this. You will have to solder two wires directly on the main board of the FCB1010.

You will have to wire the + of your power supply to the 5 volt pin of the main board. I chose the actual output of the 7805 voltage controller as it is easy to find and your 5 volts from your power supply will be filtered (a bit) if necessary by the capacitors on the existing circuit. The middle pin of the 7805 is connected directly to ground, so it can be used to connect the – wire from your 5 volt power supply.

3- Use USB power

Well, the sad news is that the FCB1010 does not have a USB connector. Communication is via old school standard MIDI plugs. All is not lost, though, as you can use the MIDI IN connection to provide 5 volts to the FCB1010.

In the picture above, I put an arrow pointing to PIN 4 of the MIDI IN connector. In theory, this pin “might” carry 5 volts from the MIDI instrument or computer connected to the FCB1010. In practice, many instruments and computer do not provide 5 volts on PIN 4, or not enough power to feed the FCB1010 internal circuit. My circuits do. I’m like that ( https://practicalusage.com/midi-experiments-arduino-as-master/ ). But what you can do, is use an alternate PIN, like PIN1 (just to the left of PIN 4 above) and “inject” 5 volts on the MIDI IN connector. Then use PIN 3, the rightmost pin, to “inject” ground. Connect these pins to the 7805 as above. Of course, to inject the necessary power, you would need a 4 or 5 conductor MIDI cable… good luck finding one!

I would recommend that if you want to go the full MIDI modification, you take a look at https://el34world.com/Misc/Music/FCB_4.htm who used a good approach to creating a complete and flexible mod.