Quick SE MIDI Mini tuning

VCO Calibration

This was also a simple job.

The only problem with this Studio Electronics MIDI Mini was that it wasn't tracking very well, in particular in the high octaves.

I started out by calibrating the PSU, but it was already almost spot on (at around +/- 10.05V or something) but I did my best to set it to exactly +/-10.00V. 

After that I calibrated the VCOs (though I have no memory of the actual procedure today), but I haven't made any specific notes about it so I can only assume it went well and didn't take too long.

Juno-6 with trigger problems and broken switch

A Juno-6 with a couple of minor issues

So my second repair was a Roland Juno-6 that had a couple of minor issues.

Trigger heard on output

One of them was that the trigger signal connected to the trigger input (for clocking the arpeggiator) could be heard on the output.

I figured it must be some audio input modification so I opened it up to have a look.

Korg Trident Mk II - My first service job

Time to get started

So, like I said in my previous post, my blog here and posts elsewhere got a few people asking if I could fix stuff for them. Long story short: I registered a business and now accept service jobs reparing synthesizers and various electronic stuff. I'm not gonna bore you with repeating all that again though. This post will be about the first job: a Korg Trident Mk II.

I don't have any photos of it closed, so enjoy the guts :)

This is a long post (Seriously long! I MEAN IT!), probably partly because the repair was a bit complicated and partly because it's my first "real" post in a long time :) I'm sure I'll make them shorter and less boring soon after this one.
If you're still interested, read on...

Excuse for not posting for over 2 years

Started Sole Proprietorship

Well, it's been a while.

If you think it's because I've been lazy, you're quite right, but not completely.

I actually registered as a sole proprietor and now have a VAT registered "business". Yay...

My blog posts and some activity on a Swedish music forum attracted some attention from people who had some stuff they needed fixed, and they asked me if I could take a look at it.

So I decided that I might as well register a business and make it right with taxes and stuff.

It's nothing big, just to keep things legal and keep my paranoid mind at ease.

I registered back in October 2014 and since then my own repairs and projects haven't been as prioritized as much as the repairs I'm doing for my clients.

I realize Oct 2014 is pretty much when I stopped posting, so .. I guess that's my excuse ;)

ETI 4600

What have I done?
I have dragged a wounded monster back to my cave...

Behold the ETI 4600!

Roland MKS-50

I so REALLY DIDN'T NEED this, but it was so cheap, it would be criminal not to buy it!

Juno-60 battery replaced but draining too fast

Juno-60 battery replaced but draining too fast

Replaced NiCd battery with lithium cell

TL;DR? Scroll down to the "Fix" header at the bottom to see how I solved it.

So this is one of those things I regret not documenting. I actually did this back in 2011 but I was too lazy to document it and of course too lazy to write any post about it.

It's not really a complicated process so I'll just describe it with words.

You see the old battery in a previous post about the Juno-60 here from May 2011, though I didn't put a new battery in at that time.

In October 2011, I just took a small stripboard, placed a CR2450 holder on it and attached it to the inside of the Juno case using a screw. I decided to use CR2450 instead of the usual CR2032 due to the increased capacity. I used two wires to connect it to where the battery pins should be soldered.

This worked well and I was able to save sounds again. Yay!

Battery draining too fast

...or maybe it didn't work that well.

Repairing a CR-78

This is a post that's been in my backlog for a while, because I knew it would take some time to write it...

Back in February this year (2013) I got a request from someone if I could repair a CR-78 with severe battery leakage. A repair-shop that was asked about it wouldn't do it because it would take too long and not be worth the time/money.
Well... I'm cheap, but I leave no guarantees that I'll fix it 100% or that I'll do it quickly, but I'll do my best. That was good enough for this guy, so he let me have a go at it.
The actual "practical" symptoms weren't actually that bad though:  Not possible to save rhythms

However, considering the massive leak, it was clear that this machine needed more than just a quick repair.
No way should anybody give up on a such a fine machine unless it's totally hopeless.
Challenge accepted!

A-Ha - I've been losing you (Cover by me)

It's time for another cover!
I really like some of the songs on A-Ha's first albums, and I chose to cover "I've been losing you."

Now, part of the purpose of doing this was of course to make a cover just because I really like the song, but another purpose was also to practice and experiment a bit with singing and mixing.
I'm not quite happy with my vocal performance as I feel it's too tense and shaky, though the original has some of that tension, Morten still manages to keep relaxed and singing in tune while I am struggling with it.
One thing I noticed is that it's really hard to keep an even volume as I tend to sing louder during some parts, in particular when I have to take high notes. I guess this is something experienced singers have learned to compensate for by moving away and towards the microphone. Now however I had to try and compensate in the recording instead, which I'm a bit lazy to go over and to properly everywhere, just in a few bad spots.

Regarding the mixing I did about 5 versions of it. The first one used a lot of stuff on the master bus (Saturation and multi-band compressor) but in the end I thought it sounded better the more I removed. Even if I didn't quite get that full punchy sound with all the mastering stuff added, it still was more pleasant to listen to without it. It really is an art to do proper mixing as well as mastering, and this was an experiment in both.

Here is the final version that I decided to go with:


The gearlist, if anybody is interested:
Roland Juno-60, Roland JX-8P, U-He Diva, U-He Zebra, NI FM-8, NI Pro-53, Yamaha CS-40M, Fabfilter Twin 2, NI Battery 3.

Roland PG-800

I finally bought one!
My JX-8P has found its mate! :)

Sorry about the crappy flash reflection

Roland SH-2000

It's not a Roland SH-1000, but almost ;)
I serviced an SH-1000 for a colleague who also had an SH-2000 that he was willing to sell.
His SH-1000 needed the keyboard contacts cleaned, so I took care of that and got the SH-2000 for a good price as "payment" :)

Roland CR-78 non-rechargeable Lithum battery replacement mod

Replacing NiCad with Li.

So, I was servicing a CR-78 for a friend and the old leaking battery had already been removed when I received the unit. After I was done with replacing all the damaged components I was going to put a non-rechargeable battery in there. It's probably possible to replace the NiCad with a NiMH battery, but they recharge slower than the NiCad (so you need to keep your machine running longer and more often to keep it charged) and I'm not sure exactly how they work when they reach their full charge.
As I'm not an expert in rechargeable batteries, I decided that the safest option was to use a non-rechargeable Lithium battery.

I think I'm in over my head...

So, someone was selling an SH-1000 in pieces for a small amount of money.
He said it was in pieces, some switches were missing, and showed some pictures of it.
I thought "How bad can it be? I'll take it."

Oh shit...

Repairing a Synare Sensor

Picture grabbed from video ;)

I was asked to take a look at this strange thing and see if I could repair it.
Supposedly it made fun noises once upon a time, but not anymore. I had never heard of it before and I couldn't really find any schematics, but I decided to look at it anyway.
(I actually fixed this back in Decemeber 2012, but I've been too lazy to post about it until now ;) )

TC5514APL-3 SRAM tester done

My SRAM tester is finally done!

I've finished a project!
This is an important milestone :)
This is probably of more importance to me than anyone else, but I still thought it might be worth writing about, since I've already posted about building this thing...
Now I can test TC5514APL-3 ICs :)
It should also work for uPD444C, M58981P and HM4334P since they're the same thing, but I don't have any of those.

International Karate (C64 music remake)

A Commodore 64 game music remake

I decided to do a quick remake of a C64 game song, just for fun.
Though I own plenty of VST synthesizers, the goal was to only use analog synthesizers and no overdub, i.e. only one instrument per sound. So you only hear the Juno-60 playing a single sound for instance.
I didn't know which song to pick, but after a short while chose the main song for the game International Karate, composed by Rob Hubbard.

Actually, I'm not too pleased with the result.
Some sounds (like the first one, heh) have an annoying ringing that I didn't bother removing. I guess I'm using too much resonance...
This was just a quick experiment so I don't care if it doesn't sound all that good.

Anyway, I thought I'd share it, so here it is:
(Update: I replaced that first sound with something better, so it's not piercing your eardrums any longer :) )

Repairing an EHX Super Space Drum

Electro Harmonix SSD repair

Somebody had noticed I had done some repairs on my own gear and asked me if I could take a look at an EHX Super Space Drum that wasn't working.
Symptoms were that it started to not trigger well until it finally gave up and refused to trigger at all. I had absolutely no idea what could have caused it and my initial thought was some sort of bad connection or other mechanical problem.
I had never repaired anything for someone else and I didn't have any pressure on me really. It was more of a "just see if you can do something about it" request, so I thought it'd be fun to give it a shot!

Unfortunately I forgot to take a picture of it so I'm using a frame of a video clip I made with it :)

The picture is from AFTER I had serviced it. Read on if you're curious about the alligator clips to the left.

Lab power supply blew up

Pop!

So, I was sitting trying to figure out why an EHX Super Space Drum (which I was repairing for someone else) wasn't working.
All of a sudden, I heard a loud pop, like somebody claps their hands once, right next to your ear.
It was really loud and felt like it almost started ringing in my ear.
Of course I had no idea what it was and got really scared I had blown something up in the EHX thing I was repairing, because it wasn't mine...
Though, I suspected it was the power supply, because .. what else could it be? It sounded like a capacitor blowing up. So, I switched it off and continued my repair using my other power supply...

When the EHX thing was done I opened the suspected power supply and looked inside.
This is what I found just laying on the bottom...

Yes, it's empty.

Sampler maintenance and upgrade

A proper Prophet 2002 repair and upgrade

I actually found a guy selling a 2nd hand R-235 potentiometer as well as the knob that goes on it. I got it in my mail about a week ago and tonight I decided to remove my ugly replacement and put the right part in.
While I had it open on my workbench I also decided it's a good opportunity to install the Lotharek SDHxC SD card floppy emulator.

Got a Roland SH-7 :)

A big old Roland from the 70s!

I bought myself a present, since my birthday is coming up... (or at least that's my excuse)

It's the Roland SH-7 !