# Determining where to hardwire a DC power supply to a drum machine originally built into an organ

#### liamc2019

Joined Jul 30, 2019
10
Hi there, I have a rhythm board and its button assembly that was taken from an old Lowrey L50 organ. I can't find a schematic online but there is the service manual to another model in it's range, the L60, and from that I've determined that the board needs 15v. Is there any way to figure out where on the board I can hardwire a 15vDC power supply to it? My idea was to take the drum machine section of the organ and make it a standalone unit. I'm also quite confused by the fact that some of the wires have two wires inside, one bare standed wire and one regular insulated wire, and that some of these wires connect to two nodes but others only one. Here are some photos of the board https://imgur.com/gallery/C4P4Dps. Many of the wires that are cut were originally connected to other modules in the organ, but the button assembly and volume control are still connected- I'm assuming like a guitar I can wire the volume control to a 1/4inch output jack. I have basic electronic experience and tools (multimeter, soldering iron) and I think I may have jumped into this project without understanding what exactly I was getting into. I'd appreciate any guidance on this matter, thanks!

#### Wolframore

Joined Jan 21, 2019
1,538
haha - i answered you in reddit... buy the $7 service manual that has the schematics... all I found was the L60 online which has 15V going to it. If you want a guess, I would guess that the power goes to the red and black (thickest) wires. Those old boards are kind of cool... the pcb traces look like worms Thread Starter #### liamc2019 Joined Jul 30, 2019 10 haha - i answered you in reddit... buy the$7 service manual that has the schematics... all I found was the L60 online which has 15V going to it.

If you want a guess, I would guess that the power goes to the red and black (thickest) wires.

Those old boards are kind of cool... the pcb traces look like worms

#### Wolframore

Joined Jan 21, 2019
1,538
That’s the concept... check the L60 schematics I sent you the link for. It should have similarities. Look at the power rails and check the wires and connections.

Nah you crash this one no one gets hurt.

#### Dodgydave

Joined Jun 22, 2012
8,688
What is ct?
Centre Tapped,you need to measure the output voltages of the transformer on the pcb, this will give you an idea of what to expect, see if any wires are going to ground, and measure from there to the Transformer secondaries.

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