Tag Archives: repair

Sampler

Roland S-330 power cable replacement

Lately my Roland S-330 sometimes hasn’t started when I’ve pushed the power button on the front. I’ve noticed that if I moved the power cable downwards it powered on, although a bit glitchy if I didn’t pull it hard enough. So when I had the S-330 out of rack I opened it up to see if everything looked alright near the power supply. And everything did, the soldering looked perfect. Moving the power cable made it turn on and off. I reckoned there must be some kind of breakage in the power cable, probably where the cable goes of the case.

I've unscrewed the metal plate in which a plastic part is mounted through which the power cable goes.
I’ve unscrewed the metal plate in which a plastic part is mounted through which the power cable goes.

As you can see the cable is run through a bit of plastic that is mounted on a separate metal plate. Removing the plastic was a major PITA, the trick is to rotate it a bit and using a pliers and push it from inside out. After the plastic bit is loose, it’s possible to open it with a flat screwdriver. As you can see in the photo below, the plastic piece has deformed the cable so it looks like a U.

The power cable has been U-shaped by the plastic piece, and it's here the power cable is damaged.
The power cable has been U-shaped by the plastic piece, and it’s here the power cable is damaged.

I bought a new power cable with a Euro plug, the original cable is an old style ungrounded plug.

The old plug (bottom) was an old style ungrounded one, the new cable (upper) has a Euro plug. This is the reason why I bought a new cable and not just cut away the damaged part of the old one.
The old plug (bottom) was an old style ungrounded one, the new cable (upper) has a Euro plug. This is the reason why I bought a new cable and not just cut away the damaged part of the old one.

To start with, I cut away the bad part from the plastic piece.

The plastic piece is modified, it's the part that's cutaway that damages the cable.
The plastic piece is modified, it’s the part that’s cutaway that damages the cable.
The evil part is loose.
The evil part is loose.

The I tried to unsolder the old power cable. That was unsuccessful and the tubing on the brown hot cable was damaged, so I fixed it with some yellow heat shrink tubing. I then cut the old power cable and solder it to the new one. Before I soldered I did remember to run the new power cable through all the bits and pieces that the original cable went through.

I tried to desolder the hot cable (brown one) without success. I damaged the brown heat shrink tubing so I put on some new. The new cable was solder together with the old one.
I tried to desolder the hot cable (brown one) without success. I damaged the brown heat shrink tubing so I put on some new. The new cable was solder together with the old one.
I mounted the new cable exactly as the old one.
I mounted the new cable exactly as the old one.

I powered it up and it worked perfectly. By the way, putting the plastic piece back was an even harder task than to remove it, but with a lot of patience I succeeded. The S-330 is now back in the rack, but before I reassembled it I took some bonus photos of it’s inside. Notice all the custom Roland chips and the HxC SD Floppy Emulator as well as all the different outputs.

Repair photos

Bonus photos

Synth

Repairing an M-Audio Venom

I’m actually not very interested in virtual analogs. With an all digital audio path you could as well use software instruments. One good feature though is that some of the oscillator waveforms are sampled from real classics. The Venom also has classic drum machine samples from 808, 909 and more. This review is quite nice:

View video on YouTube (opens external site in new window)

Anyway, a couple of months ago I pickup a (not that) used Venom for about 1000 SEK / $150. My plan was to use it purely as a midi controller since it has four assignable knobs that sends midi CCs, so I thought why not.

After a few hours use, suddenly the A3-key started to squeak every time I pressed and released it. It’s hard to describe how utterly annoying that is, I was near reinstalling my Roland PC MKII that has been turned on and worked flawlessly for 17 years (and still going strong=quality) and sell or trade the Venom for a Behringer BCR-2000. Also, there was something lose in the Venom that rattled everytime I moved it.

View video on YouTube (opens external site in new window)

With not too much too lose, I decided to try to fix the Venom. The first thing was to open the damn thing. When I looked underneath it, I was chocked to find 42 Philips screws! Insane! Not knowing which ones to unscrew to open the case, I googled for a service manual but couldn’t find one. This had to be done the hard way…

Luckily, it turned out that it wasn’t very complicated, but rather time consuming. What you have to do is simply unscrewing all the of the 32 screws that in “rectangular” holes. The 10 screws in round holes (marked by a red square) are holding the keys to the bottom part of the case. We’ll get to these later.

The red square marks the screws that holds the keys to the bottom. All other screws must be unscrewed to open the case.
The red rectangle marks the screws that holds the keys to the bottom. All other screws must be unscrewed to open the case.
All of the 32 screws that needs to be unscrewed to open.
All of the 32 screws that needs to be unscrewed to open.

So I started to unscrew. After that, the top part could be lifted a couple of inches. The only thing left to completely detach the top from the bottom was this lead that connects the keyboard to the motherboard.

The lead that connects the keyboard to the motherboard
The lead that connects the keyboard to the motherboard
The motherboard and other circuit boards are attached to the top piece. The arrow marks where the keyboard lead is connected.
The motherboard and other circuit boards are attached to the top piece. The arrow marks where the keyboard lead is connected.

As soon as I opened the Venom, this little piece of glue fell out of it. This was also the piece that caused the rattling.

It was this little piece of glue that made the Venom rattle.
It was this little piece of glue that made the Venom rattle.

The next thing was to locate what made the key squeak. An interesting and quite confusing thing is that all white keys are marked E1 to E7, plus the C6 key that is marked E8. All black keys are marked C4.

For some reason all white keys are marked with and E and a number between 1-7. The most upper key, the C5, is marked E8. All black keys are marked C4.
For some reason all white keys are marked with and E and a number between 1-7. The most upper key, the C5, is marked E8. All black keys are marked C4.

You can also see the key spring. To remove the key, the spring must first be removed. Removing the spring is a no brainer, just lift the spring in the bottom or the top. As soon as I hade removed the spring from the squeaking key, the squeaking disappeared. I put the spring back and then the squeaking returned. I tried to swap the spring with one from  another key, but that made no difference.

To remove key, first remove the spring (notice that the spring is still there in the picture), and then push the key in the direction of the red arrow
To remove key, first remove the spring (notice that the spring is still there in the picture), and then push the key in the direction of the red arrow

I figured I had to remove the squeaking key and one other key to compare them and see if there was any visible difference. The simplest way to remove a key is to push it towards you, the same direction as the arrow in the photo. It doesn’t take much force. Putting it back isn’t hard either.

Two removed keys
Two removed keys

Looking at visual differences, there wasn’t any, other than the low quality plastic stuff on the edges left there from manifacturing. You never see stuff like this in an old vintage Roland synth…

Next thing to try was to swap the squeaking key with another non-squeaking one. The bad boy was the A3, so I decided to swap it with the A5 key. To my surprise, the A3 stopped squeaking and so did the A5. Don’t ask me how, but this was the solution! I put the Venom back together, only using a third of the screws just to make sure that it still worked. Which it did! Case closed!

BONUS:

During my investigation I also removed the key circuit boards to see if the error was there. Looking back, this was totally unnecessary. I took some photos, so I thought I might as well post them here.  Have a look at the gallery below.