Music & Gear

JX-8P reloaded

Montag, April 10th, 2006

Yesterday I fetched this classic piece of gear out of my cellar.

I am guilty. The cellar is wet and mouldy and a hostile environment for electronic equipment, but I closed my eyes and left poor JX vegetating there for the past ten years. A wedding musician gave it to me after it was worn and broken from heavy use. I remember that I tried to repair it but wasn’t successful in the end.

Dear JX, I promise to make up for your sufferings. To be continued.

Please hold the line

Dienstag, Februar 21st, 2006

Being held on hold is a familiar customer experience today. After all, on a free call you may push the phone’s speaker button and try to relax or do something useful with your time. And sometimes, after a few minutes, you find yourself caught by a nagging and senseless piece of waiting loop music. They got you, if it still loops in your brain when you go to sleep.

Download MP3 (~3.74MB)

Micro-Sat 500 repair

Samstag, Januar 7th, 2006

Last year a friend of mine called me for assistance with his „new“ speaker set that he had just acquired second-hand from an unknown guy. In fact, the friend had placed an ad to sell his portable keyboard and then somebody called him and offered a speaker set & powered mixer in exchange that the guy would even bring in for a smooth transaction. They did the deal. A few days later the friend was taken aback by the, um, strange sounding satellite speakers and I agreed – we heard sizzling highs on the left and sizzling highs on the right but no mids anywhere, mids totally absent.

The Solton Micro-Sat 500 set consists of two passive SP104 satellites (100W RMS/200W Peak, 4Ohms) and a passive SP515D subwoofer (500W RMS/800W Peak, 2x4Ohms) with integrated crossover and it sold for 2350,- Deutschmarks (approx. 1150,- Euro) list price in the late 1990s. Solton recommended their 10 channel powered mixer ACS10/500 to be bundled with the Micro-Sat 500, and this is what my friend got instead of cash.

After removing the grills I saw two shiny 8″ mid-range chassis and a ¾“ tweeter per satellite. Would you think that one of these 8 inchers was dead? Maybe. Would you imagine that all four were dead? Not really. The tweeter is labeled Craaft F1 and reminds me of a popular Foster-Culver / Fostex driver that I think to have seen before on Dynacord, Hughes & Kettner, LEM and other speakers. This is a good one, probably the most expensive part of the SP104.

Using wood screws instead of drive-in-nuts for grills and speakers is not a good decision. And what about the prototype-style crossover with parts glued on a wood plate instead of PCB mounting? Would be a real fun to repair this thing. And, by the way, the 8 inchers look like bottom-of-the-line steel chassis („organ speakers“), yet adequate but with a slight cheapo appeal.

At the beginning I wouldn’t have believed that all four mid-range chassis are dead, but in fact they were. So I took out the cutter and became a speaker investigator. Three chassis had a broken coil wire right at that point where the wire is guided out from coil to cone and where coil and cone and suspension are glued together. Usually, at this critical joint, the wire is coated with laquer or glue to prevent it from mechanical stress due to vibrations. It seems that this protection has failed in the course of time and then the wire got thinner and thinner until it burned out. My assumption would be that this is a defect of fabrication.

The fourth chassis obviously has been grilled by overload; think of a musician on stage who tries to get audible mid-range sound from the only one left of once four mid-range speakers.

When I contacted Solton they quickly responded with the address of a service technician who sent me four genuine replacement chassis for about 120,- Euro including VAT and shipping, which is a very fair price in my opinion. The replacement chassis had labels on their back revealing that these are TVM (Tesla) ARO 6608 speakers from Czech Republic. Using Google Cache I found out that they once retailed at 229,- Kc per piece (approx. 8,- Euro as to date of this article).

Korg 01/W sticky keys repair

Samstag, August 11th, 2001

This is meant to be a description of my experiences concerning the „sticky keys“ problem with the Korg 01/W. See the excellent On-Line Guide to the 01/W by Ken Westover or join the 01/W mailing list to get more information on the 01/W. Maybe you want to listen to the 01/W factory demo while reading this stuff. Recorded it with the 01/W directly plugged into the AX-44 expansion unit of my Yamaha DSP-Factory.

Update (May 15, 2007):
Emmanuel KATZ sent me his french translation Réparation du symptôme des «touches collantes» du KORG 01/w of this article with the kind offer to provide it here for download, available either as zipped MS Word document (8.2 MB) or as PDF file (1.5 MB).
Besides owning and playing synths like Korg 01/W, Korg 707, Roland U-20 and E-MU Classic Keys, Emmanuel’s profession is being a project leader in development. Visit him at

Update (May 20, 2007):
Robert Viands posted a link to his website where he describes his experiences with fixing sticky keys on the 01/W without taking it completely apart. Check this out.

Update (August 03, 2008):
My 01/W suffered from a „no sound“ problem due to leaking electrolytic capacitors on the mainboard. See this article for a description of how this could be remedied.

Got the 01/W in 1992 as the winner of the monthly Keyboards Give-Away. Since then there were many hours playing the instrument on stage and at home. About four years ago some keys moved more and more sluggishly until they finally got stuck every now and then. Recently the battery went low and I decided to get rid of the problems by fixing them myself.

Unplugged the power cable and put the 01/W on a thick cloth to prevent damage on the panel. Removed the bottom plate and looked at tons of printed circuit boards. Decided to avoid static electricity and sat down to have a coffee and meditate.

bottom-side up

The joystick panel shield. It had to be removed to get the keyboard out.


Part of the CPU board. The CPU board had to be removed to get the keyboard out. Red circle showing the battery holder. The battery is a CR2032.

part of the CPU board

The aftertouch board and a closer look on the activator strip.

aftertouch board and a closer look on the activator strip

The CPU board after being removed. Again decided to strictly avoid static electricity.

CPU board after being removed

Lots of screws lying around well assorted for later reassembly.

lots of screws

Even more screws, and again assorted.

even more srews

The keyboard after being removed without any hurts. Thought the fridge would be a nice background. Paid attention to the aftertouch strip.

keyboard after being removed

The aftertouch strip.

aftertouch strip

The remains of the 01/W, bottom-view.

remains of the 01/W

The remains of the 01/W, top-view. Nice fridge, isn’t it?

remains of the 01/W

The keyboard viewed from the left. Tried to come across the mechanism. Basically it all works without the grease. The key is hanging on a small plastic clamp on the bottom side. The action feeling is produced by the combination of a spring in the middle and a lead weight on the inner front.

keyboard viewed from the left

It took some time, still tried. I have learned that it is not just the lubricant getting sticky which then causes problems but the lubricant combined with the dust & dirt getting stuck even worse then in the mechanism. After cleaning the keyboard it slightly worked without any grease as there is nothing in it to rub inherently. The lubricant does it’s job if you deeply strike the keyboard bending the keys to the left or right.

took some time..

Meanwhile put the keyboard onto the table and removed the fixing strip.

the fixing strip

Removed a key and meditated.

removed a key

Removed some more keys and meditated.

removed some more keys

Removed all keys and suddenly knew where all the dust and dirt had gone. Ken Westover writes: „Several users highly recommend completely removing the delicate activator strip before doing any work. This takes more time, but activators are easily damaged while working on the keys.“ Didn’t believe this and thus had to pay my bill: Later, while re-fixing the keys, there were three activators bent off. Thank god, they did not break and I had a fair chance to fix it. Of course, I had to remove the activator strip for this, so why not do it right now ?

removed all keys

Cleaned the keyboard and fussily removed the sticky old grease. Spent a long time looking for the right lubricant. Took an ivory key with grease on it and went to some electronic and modelling shops to hear what they would recommend. Actually Klüberpaste, which is also used for VCR or tape-deck repairs, made it. Did not try teflon-lubricants that may be the better choice in the long run (out of stock). Prepared 10ml of Klüberpaste in a shot.

cleaned the keyboard

The freshly greased keyboard. Needed only 2ml. Reassembled my 01/W and got lucky. It’s a bit like having a new one. New battery and one of the best keyboards one can have. Don’t know how long the lubricant will do it, but yet it works great.

freshly greased keyboard

PS: Still great in 2013 ;-)

Leslie 710

Mittwoch, Juli 25th, 2001

These are a few photos of my Leslie 710. Took them in here for sentimental reasons, although the quality is poor due to the Philips Vesta PCV680 webcam that I had to use for shooting.