Casio SK-1 MIDI Adapter

Completed Casio SK-1 MIDI Adapter
(Click for full res.)

On the up side, I completed the PCB for the Casio SK-1 MIDI adapter that I’ve been working on. On the down side, it doesn’t work. After reassembling the SK-1 after cleaning it, everything seemed to work great. Then, after I hooked up power, fitted the PCB into the enclosure (without gluing it yet), and attached the ribbon cable to the SK-1’s keyboard connections, the SK-1 just makes a humming / buzzing sound. I think the problem is likely some part I missed soldering on top of the board or something. Or possibly a bad PCB-side connection on the ribbon cable.

When making one’s own double-sided PCB, the holes aren’t plated on the inside with metal, so one has to solder parts on both the top and the bottom of the PCB. It was a bit of a hassle to solder things on both sides, but I thought I it taken care of in most places. Maybe I’m wrong, though… Ah well, tonight (or sometime this weekend) I’ll remove the PCB, remove the power lines and ribbon cables, and double-check everything against the schematic.

Here’s some of the pictures from my work on this last night:

· Resharpened PCB drill bits, acquired from eBay. They are really, really small. The shafts on those bits is 1/8″.
· A very unshaved me, wearing a respirator and safety glasses. Both are needed as drilling and cutting PCBs makes lots of fiberglass / epoxy dust.
· One of the bits (26 mil, I think) in the chuck of my Dremel.
· The pile of parts needed for assembling the adapter, including some spare resistors sacrificed for their leads, which were needed to solder vias.
· All vias soldered, and jumper A placed to turn off wrapping of notes from outside the keyboard’s normal range.
· All parts (except for microcontroller, ROM, and wiring) attached to the board.
· Completed board, with power wires and ribbon cable.
· Ribbon cable attached to Casio SK-1’s keyboard connection.
· Power wires attached to the external power jack and the PCB fitted next to the speaker.

So, that’s that. I’ve still got more to go with regards to fixing everything. I know it’s getting power… I just don’t know what else it is doing yet. By the time I had the board installed it was nearly 11pm and I’d been working on everything for about 4.5 hours. I needed a break. Hopefully things will progress further tonight / this weekend. At least I don’t work until Monday or so.