As the rails for the filter boards are in order, I finally got to focus on some bezels for these boards. Since I don’t have any mechanical drawings, all these bits need to be tackled on the fly and I couldn’t start with the bezels until I had the board/rail spacing figured out. Otherwise, I would’ve probably done all the mechanics much earlier, maybe whilst still looking for parts.
Material-wise I chose to go for aluminium as it’ll match the metal parts of the casing neatly. For mounting, I decided to try soldering L-brackets to the bezels (that is, no ugly screws on the front side) and these brackets are in turn fastened to the filter board. When a potentiometer is fastened to the bezel it will also support the overall structure a bit. Having done a bit of solder patching with the QuadSID I knew to expect that this would require extreme/crazy/insane heating, so I set up a heater gun at maximum setting right next to the bezel to provide additional heating from the opposite side.
The board / backplane supports are starting to come together, so it’s picture time! First up, filter board support rails:
Plenty of leftover parts for industrial racks at work, so the rails were a obvious choice. From here, on to measuring the backplane standoff mounting points..:
The backplane support needed a bit of cutting..:
And finally, both supports in place with some filter boards installed..:
I’ve spent quite a while verifying, re-verifying and re-re-verifying board traces for this project (boooooring!), so just to get something bit more concrete happening I decided to see how the boards would fit inside the casing..:
Looking pretty ok, time to start on the mechanics for the filter boards at least..
Talking about the problems sourcing the BPF board capacitors for the vocoder project with various buddies, SP-Elektroniikka located in the city of Oulu (northern Finland) eventually popped up on one of these discussions. Having stripped quite a few old devices for possible usable/suitable parts with weak results, I’d rather see this project advancing instead sticking with my initial plan of making it 99% out of recycled parts. Thus, some shopping is called for.
Anyway, as I was told, one specialty of this electronics shop is guitar parts and that meant “obscure” value capacitors (used for passive filters and such) among others. So, quick look through their catalog and what do you know, nearly full range of E-series caps indeed! Wonder why this shop didn’t pop up in the various searches I have made earlier?! Given what I was about to order (maybe 5€ worth of capacitors), their shipping costs were ridiculously high in comparison. Not that they had any other parts that were on my “pending list” to justify the costs either. Lucky for me, it turned out that one of my friends happened to live almost next to this shop so I asked him to buy and deliver these parts to me. So finally, I now have all the required capacitors in my hands. Couple of values had to be made by combining a few other caps, but nonetheless my search finally came to a end! Much thanks to Break for the help <3
Focusing to this project after a while, I decided to finally complete etching rest of the boards..
Looking sweet but still a long way to go. Sourcing the odd value capacitors used on the BPF boards has turned out more of a problem than expected. It seems to me that the electronics industry has moved over to fewer sizes (capacitances) from the full E-series, so capacitors that were common during early 80s are hardly so anymore. Either this or its just the electronics shops in Finland that are total shite :)