I have had in my possession for a few years, a Roland D50. I bought it from a guy who probably bought it from a guy who bought it from a guy etc. The left headphone channel hasn’t worked for as long as I’ve owned it and since I’m going to be selling it soon I thought I’d better fix it.
What surprised me the most upon opening the case (having never opened a synth before) was the number and complexity of components. I’ve watched interviews from analog synth fans downplaying the technical aspects of digital, as if the internals would be a couple of IC’s and a very spartan PCB.
Access to the I/O array board is gained by first removing the mainboard. The length of the interconnecting wires allows this to be done without unplugging anything.
While I had the case open, I also took a quick look at the power supply. It is dual rail ±12V (to drive op-amps at the very least I suspect) with a third +5V output for TTL.
The problem was traced back to a faulty capacitor. These 47µF bipolar electrolytics are located adjacent to the headphone jack and were something I didn’t have spares for. Jaycar had some in stock but by that stage it was 7pm and they were closed for the day.
The next morning I bought replacements and set to work finishing the repair. My current residence is conveniently situated between the two local hobby electronics stores; Jaycar and Altronic. The original caps have “BP” printed on them for “BiPolar” while the replacement caps read “NP” for “Non-Polarized.” They translate to the same thing.
A couple of the pads lifted from the PCB when I removed the original capacitors. Fortunately I was able to connect the leads directly to nearby components and bypass the broken pads.
All fixed! Both headphone channels have audio output again. :3