Kurzweil PC361 blows fuses often

[zdawgster]

I have a Kurzweil PC361. Please bear with a brief history of the keyboard so you have all necessary information.

I brought it with me from the US to Nagaland, which is a small state in northeast India. When I got to India (where electricity is 220 volts), I forgot to put in the appropriate fuse in the PC361 and change the setting to 220 volts (or 230 as is printed on the red fuse holder). So after turning it on, the fuse promptly blew. After replacing the dead fuse with a couple of the correct kind (1/4 amp, 250V fast blow), the PC361 seemed to work fine. I hope nothing got damaged during the PC361's brief exposure to 220 volts.

I then discovered that the scroll wheel was no longer working. Turning the scroll wheel moves the number back and forth between adjacent numbers (e.g. 1-2-1-2-1-2....etc). I found that if I press on the scroll wheel while turning it, then it works a bit more normally (but not perfectly). This led me to believe there was some physical damage to the wheel during the journey from the US to India. I assume that it was not affected by the brief exposure to 220 volts....?

My real problem is this: I have blown the fuse about 4 times now in the space of 6 months. I have hardly used the Kurzweil during this period; maybe only averaging an hour a week. Each time it has happened when I switch the unit on. As far as I can tell there has been no power surge or abnormally high voltage coming through the main power supply. The first few times this happened the PC361 was plugged into a UPS which also regulates voltage. The last time it was while the unit was plugged directly into the mains power supply and the voltage was perfectly normal, as far as I could tell.

I suspect the keyboard is at fault and not the mains power supply. I don't know too much about electricity or
electronics, but at this point I have two suspects: 1) my Radio Shack fuses, though the right specs, are absolute crap and blow with the slightest change in voltage, or 2) my PC361 sometimes draws too much current when I flick the power switch on, and so the fuse blows.

If 2) is correct, then my PC361 needs servicing, but Kurzweil doesn't have any authorized service center in INDIA, and I sure don't want just any idiot who knows how to plug in a soldering iron open up my Kurzweil! But I can't keep on popping in new fuses every day because I'm having trouble locating these fuses in town.

I'm very frustrated and need some help. Even if I'm forced to use a local person to pry open my PC361 and poke around, the more info I can supply the better it will be.

Thank you very much for your help,

Zingrin Shishak

PS. I forgot to say that the PC361 makes a humming sound which seems a little abnormal. It's not terribly loud but is definitely noticeable. Sign of damage somewhere or is it normal? I can't remember hearing it before my present adventures.

[Bob]

I would guess that your Kurzweil needs servicing. It probably happened when you plugged it into the 220 line.

I would start with the Kurzweil repair site to see if you can find someone locally to ship it to

http://kurzweil.com/support/repair/

[Dave Burris]

It's quite possible that the overvoltage damaged a bypass capacitor that now causes the power supply to draw excessive current. The dialectric may be partially broken down but not shorted. Could possibly be a few other things as well. The fact that the unit still works probably indicates something marginal in the power supply. Could even be that a regulated voltage is now unregulated, raising the overall volatge and subsequently the current draw of the entire system. This would stress the fuse more than normal, particularly the inrush current at power on.

You should have someone check out the power supply and protection circuits. The hum could also be indicative of a damaged capacitor or regulator gone bad.