Kurzweil K2500RS, Musician'S Manual

Page: 440 / 530

Maintenance and Troubleshooting
Power Problems and Solutions
28-4
Finally, magnetic Þelds can be a source of interference. The area surrounding the K2vxÕs Alpha
Wheel and alphanumeric pad is sensitive to Þelds from large transformers in power amps; keep
them at least a foot away from the K2vxÕs front panel. Smaller gear like drum machines and
hardware sequencers can also cause interference.
Power Problems and Solutions
The K2vx is quite tolerant of voltage ßuctuations, noise, and transients in the AC power it
receives. The input line Þlter and grounded power cable will protect against even large
amounts of noise from motors and the like while the built-in Þlter coupled with the fuse will
protect against all but the largest transients. If your installation is actually suffering from line
noise or transients, most likely your other equipment will be suffering more than your K2vx.
Very low line voltage or severe voltage dips are a problem for any computer-based instrument.
When the K2vx is set for 120 volt input (the normal North American setting), it should function
down to 90 volts. If the line voltage drops below 90 volts, a special circuit halts all activity to
protect against software crashes or damage. When the line voltage returns to and stays at an
acceptable level for at least one second, the computer will automatically restart. The net effect is
just as if you had performed a soft reset. Continuous low line voltage or transient dips will
never produce symptoms other than unexpected soft resets as just described. Any other
problems such as distortion, disk errors, or lost data are caused by something other than line
voltage ßuctuations.
Soft resets from line voltage dips are most common. These are easily identiÞed because the
reset occurs coincident with the building lights dimming, stage lights or power amps being
switched on, or air-conditioning equipment starting up. The solution in all cases is to get a
more direct connection between your K2vx (and any other computer-based equipment) and the
buildingÕs power. Floodlights, large power ampliÞers, and motor-operated devices should use
a separate extension cord; preferably they should be plugged into a separate outlet.
Chronic low line voltage is best conÞrmed by measurement. Readings below 100-105 volts
mean that even small dips could cause resets, while readings below 95 volts (accounting for
meter inaccuracies) are a deÞnite problem. Again, the best solution is to separate your heavy
lighting and ampliÞer loads from your K2vx and other synths on separate extension cords or
separate circuits when possible. If the actual building voltage is that low, use of an external
step-up transformer or voltage regulator is recommended. We DO NOT recommend changing
the line voltage selector to 100 volts (or 220 volts in Europe) because overheating or blown fuses
may occur if you leave the K2vx at the lower setting and use it later at a normal voltage level.
Troubleshooting
Naturally, weÕve done everything possible to ensure that your K2vx arrives free of defects. And
thereÕs a good chance that thereÕs nothing wrong, even if youÕre not seeing the proper display
or hearing the sounds. Carefully check the following things:
Make sure that your power supply is at the right voltage, and is functioning properly.
Make sure the power cable is connected properly.
Adjust the display contrast if necessary (with the Contrast parameter in Master mode). If for
some reason you have trouble reading the display, even after adjusting the Contrast parameter,
you can also adjust the contrast by holding down the ENTER button and turning the Alpha
Wheel. If this improves the contrast, immediately return to the Contrast parameter and adjust it
slightly. This will cause the K2vx to remember the current display contrast level, and should
take care of any difÞculties you may have been having. If this procedure doesnÕt work, itÕs time
to contact your dealer.