The Maxi-Korg project languished for a while before a flurry of activity got it working back in March. Let’s review my to-do list from September of 2020 as a means to provide updates:
I still need to refinish the wood cheeks to use the originals until I can get new made
Still using the original wood. Once it was all back together I decided I needed some quality time making sounds with it before I took it back apart for any reason. This is not to say I won’t ever replace the wood, but probably not for a while. It can only be original once.
I need to clean up and remove some paint speckles around the bodywork from someone painting with a roller near this – hopefully it is latex paint
This was time consuming and as one can imagine with TINY paint spreckles it was tedious. After trying some mild cleaners and wood or plastic tools it was decided that my fingernail was the best implement for removing the paint from the textured metal bodywork. There are some areas where there is still a haze of discoloration from paint, but I can live with it.
Looks pretty good above. Superglued key is still holding together! I bought some new black oxide hardware for the panel – I’ll see if I can get my son to swap it sometime soon. Keeping company with some frequent collaborators. I spy a Source and a System 100.
With the keyboard all cleaned up, the circuit boards capacitors replaced and much general clean up attended to, I turned my attention to the controls – the sliders, pots and switches that you interface with to play the instrument. The Traveler sliders in the VCF section felt awful when I first checked out this synth. They were stiff and notchy when they would move. I figured worst case I would have to find suitable replacements for the 4 of them. I don’t remember if I even tried any of the other controls – once I got bad news I just moved on.
Wood. Seems incongruous on a piece of sophisticated electronics. I offer a few reasons why: It’s a Japanese thing – the harmony achieved balancing the electronics and metal with the wood; it’s a vestigial thing – from the days when a keyboard meant a piano forte; it’s a manufacturing thing – in 197* plastics were not so hot and a wood case was just easier to not mess up. Being practical I am going to say it’s a combination of the three.
So what about wood anyway? The smoke cleared enough that I was comfortable going outside to do some sort of work after nearly a week of awful smoke from all the fires here in California. I grabbed the wood chunks that go at either end of the keyboard (that I bet the last guy who owned this keyboard called cup holders), some sandpaper and some restore a finish and headed outside.
Okay, you read in the last post about how the easiest way to come up with a capacitor list is find someone who has done the job you are looking to do and get them to give you their list. And then I talked about how I made a list, but I didn’t post it. Well, by popular demand, here is my Korg 800DV capacitor list. I will give you the board by board list, the specification changes I made to try and buy in bulk and the final list I ordered from Mouser.
Electrolytic capacitors go bad eventually, Maybe not tomorrow, maybe not next week, but eventually they go bad. If I was a tech fixing this Maxi-Korg on a budget for a kid who just dragged it home from a garage sale I would probably insist on recapping the power supply and replacing the tantalum capacitors, doing some testing and sending her on her way with a $60 repair bill and a few words of encouragement to take care of this neat thing she is now the keeper of.
That is not the situation. I am a guy who likes to do it once and do it right as much as possible. I am going to replace all the capacitors. Top to bottom, inside out – even the couple of tantalum caps tacked onto the back of some of the sliders. And why not there’s only like 60 or so.
Covid-19 has slowed the delivery providers to somewhat of a crawl, but I think FedEx is handling it better than the others. The Maxi-Korg was delivered only a few days later than was initially estimated. I didn’t take any pictures unpacking it – looked just like the auction photos. Was poorly packed, but somehow made it with only one of the rubber feet poking its way out of the box. I can live with that.
When I spend more than a few hundred dollars on something I tend to dig right in to see what I am up against. The sliders and pots were really sticky and hard to move so I opted not to turn it on, but rather save that fingers-crossed moment for after replacing all the electrolytic and tantalum capacitors. No sense in risking too much electricity getting through a shorted open capacitor and taking out a transistor.
My birthday is next month and every year I buy myself a piece of vintage gear (not sure why, but I hate the word gear for music equipment) – usually it’s a project and the price reflects this, so I start my search well in advance of my birthday – hoping something will turn up. Last year it was an untested Roland Jupiter 6, the year before was a Moog Source. This year I was thinking either a Korg Maxi-Korg or a Roland SH-7 or RS-505.
The other night this Maxi-Korg was listed on eBay for more than I wanted to spend on one, and it was untested, but I figured I’d submit a offer I was comfortable with and see what happened because sometimes you have to throw caution aside and go for it. Especially when you are looking at something you’ve wanted for a long time. Early the next morning my phone chimed because my offer was accepted!