How to Fix Electronic Music Gear
By Anderton |
How to Fix Electronic Music Gear
Repair or replace? Try repairing first…
by Craig Anderton
Your keyboard or multieffects is ailing. In many cases, you can be the doctor and fix what’s wrong—and save repair costs in the process. We won’t get deep into the weeds, but cover the essentials.
FIRST, DO NO HARM
The last thing you want to do is create new problems. In the medical world, this is called an iatrogenic illness—an illness caused by medical treatment. A slipped screwdriver while power is on, a broken connection, or destroying a circuit board trace could put an end to your gear. Repairs require care, patience, and being very deliberate in your actions. And did I mention patience?
The cardinal rule is do the easy stuff first. Although that may not solve the problem, if it does you’ve saved yourself a lot of work.
START WITH THE EXTERNALS
Gather as much information as you can on symptoms. For example if there are no signs of life at all—no lights, no nothing—then it’s likely a power supply problem. If a keyboard has notes that don’t sound, it could be the keyboard itself, or the cables that connect to it. In either case, those are easier to check than trying to find out if an oscillator IC had died.
Start by checking cables. I fixed a keyboard for a friend who had complained of intermittent operation. By checking cables first, I noticed that the IEC AC cord felt a little loose in its socket. I tried a tighter-fitting cable, and that solved the problem. Also look for signs of abuse, like chips or dents. That could mean something has become unseated.
If there are external fuses, check them. Also check the power supply voltage switch, if present. One guitarist couldn’t understand why the Hughes & Kettner preamp he bought sounded so bad—until he realized the voltage switch was set for 240V in a 120V world.
- Always unplug the gear before opening it up. No exceptions.
- Place blankets, pillows, or something else that prevents the possibility of scratching your gear as you lay it on the operating table. Furthermore, thick pillows and the like can also “cradle” sections of the gear, like holding a panel at a 90 degree angle.
- Go online and try to find your gear's service manual. It will often include instructions for disassembly, and these can be worth their weight in gold—you definitely don’t want to loosen screws that shouldn’t be loosened. The service manual should also tell you if some case sections snap into place, which will imply how to unsnap them. Don’t discount YouTube videos from owners, either.
- Grab a cup, plastic food container, or whatever to hold any screws or other components you need to remove. Keep the top on when not in use! If you tip it over and screws go flying into a carpet, it’s not fun.
- Be aware that crucial screws for disassembly may be “hidden” under a “no user serviceable parts inside” sticker, a removable nameplate, or other sneaky location. Again, a service manual will identify these but if you don’t have a service manual and perform “unscrew while crossing fingers,” the last screw you need to undo might not be visible.
- If all screws you need to undo are the same type, great. But if not, draw a diagram of which screws came from where. Don’t think you’ll remember which screws go where.
- Often, panels can be separated from the main section of the gear. However the cables connecting them might not be very long, and pulling the panel away from the body may pull a cable out of its connector. When you first open a piece of gear, grab your smartphone or camera and take close-up pictures of the insides. They should be detailed enough so that if every cable was unplugged, you’d know where to plug them back in.
- Make sure any separated pieces are supported well. You don’t want a front panel falling over and ripping a few wires in the process.
CHECK THE OBVIOUS
- Before touching anything, observe. If you see any leakage from a backup battery or crystals forming on the terminals, replace it immediately and hope any damage is minimal. In fact if the gear is more than a decade old and the battery has never been replaced, it’s cheap insurance to order and install a replacement.
- Look for any physical deformities in components, like swollen electrolytic capacitors, or discoloration in resistors (which may indicate heat damage). One of my more interesting cases was an OB-8 whose ICs and sockets used dissimilar metals, and conductive hairline crystals formed between the metals. I used a fine metal brush on the IC pins, and the OB-8 was fixed. However if you think a part may need replacing, don’t do anything yet; there may be no problem. But since you’re observing anyway, take notes. If you see any evidence of smoke or there’s a leftover “burning electronic part” smell, you probably won’t be able to do the repairs yourself.
- Check for internal fuses. If a fuse is blown, pay attention to how it was blown. If it simply opened up and there’s a gap between the fuse elements, it may just be old. But if there are little fuse particles inside the fuse, it might have blown violently from a sudden rush of excessive current. This warns you that there may be a serious relatively serious problem; when you power up to test later, be prepared to turn off the power switch as soon as you turn it on.
THE FIX IS IN
- The first thing I do is disconnect connectors and then re-seat, one at a time, going through every connector at least once. Metals can corrode or oxidize, especially if you live in an environment with air pollution or salt water. I can’t tell you how many times simply re-seating connectors has solved problems, with no further attention required. For example, I had an Alesis Ion where three keys didn’t work. I thought maybe there were key contacts that needed cleaning (there weren’t), but it was simply that the connectors connecting the keyboard to the main circuit board needed re-seating.
See all those ribbon connectors? Simply re-seating them can often solve problems.
- Not all connectors pull out cleanly. Some might have a little lip or latch to hold the connector in place, and you need to push on the latch gently to unseat the connector. Also, you want to be very careful not to bend any pins, as bending them back will weaken them. Pull connectors straight up; if possible, wedge a small screwdriver tip under each end so you can lift both ends of the connector evenly. Similarly, when re-seating make certain that all pins are in their respective holes before giving a final push into place.
Many people who perform repairs worship at the alter of Caig Laboratories' contact cleaner and de-oxidation products.
- While the connectors are off, check the pins for corrosion or oxidation. If present, squirt a little metal-on-metal contact cleaner on a Q-tip, then use it to wipe down the pins.
- ICs in sockets can also cause problems. In this case, don’t take them out and re-seat them; it’s too easy to bend or break the fragile pins. It’s sufficient to use two screwdrivers as described above to raise the IC about 1/16th up from its socket (i.e., the pins don’t come out all the way), then push down again. This wiping action should be sufficient to clean the contacts.
- With pots that pass audio, a scratchy pot will be obvious when you listen. With pots used as encoders with digital circuitry, the results are less predictable—it may seem difficult to select presets, or a mod wheel might behave unpredictably. If the pot is a sealed type, replacement is your only option. If the pot has an opening and the resistive element is exposed to the air, contact cleaner is usually all you need. Be aware there are different types of contact cleaner; for most pots, you want the metal-on-plastic type. I have the full set of Caig contact cleaners for metal, plastics, gold-plated contacts, etc.
- Look over all soldered connections. While “cold” solder joints are unlikely in modern gear, especially on circuit boards, if wired connections are done by hand the possibility always exists. Another possibility is that the solder's flux did not burn off completely. If you’re handy with a soldering iron, touch up connections that look sketchy but be careful the heat doesn’t affect any plastic parts.
ARE WE THERE YET?
In my experience, most problems are mechanical. One of the weirdest fixes ever was when there was signal going to a synthesizer’s 1/4” output (as seen on an oscilloscope), but it never made it out of the synthesizer. A little investigation and a few choice swear words later, I found that the output jack had an internal short. Replacing it solved the problem.
These days, many “repairs” don’t get to the component level, but do a board swap. It’s just too time-consuming to check individual components, unsolder them, and replace them. However if you can do the fixes yourself, you won't have to wait for some board to show up (if in fact you can even find one) and your gear will be happy again.
The synth in the photos is my beloved Alesis Ion, which had three keys that didn't work and a sketchy mod wheel. 30 minutes later, it was back in active service - and better than ever.
Craig Anderton is Editorial Director of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.