Classic Computer Magazine Archive COMPUTE! ISSUE 78 / NOVEMBER 1986 / PAGE 8

Readers' Feedback

The Editors and Readers of COMPUTE!

If you have any questions, comments, or suggestions you would like to see addressed in this column, write to "Readers' Feedback," COMPUTE!, P.O. Box 5406, Greensboro, NC 27403. Due to the volume of mail we receive, we regret that we cannot provide personal answers to technical questions.

Overseas Computing

I would very much appreciate an authoritative answer to my questions. I plan to purchase a Commodore 128 computer with 1902 monitor, 1571 disk drive, Datassette, printer, and joysticks. This set will be used in Poland where the power supply frequency is 50 hertz and the voltage is 220 volts AC. I can obtain a suitable step-down transformer to convert the voltage to 110 volts, but the frequency will be unchanged. Will this system work correctly with 50-hertz current?

I have visited numerous dealers in the New York City area. Some say that this equipment will work in Europe, others say that it won't work, and others simply don't know. My letter to Commodore has not been answered. I can easily purchase all of these items in Western Europe, but would prefer to buy them here and ship them to Poland. At the current exchange rates, this system will cost roughly twice as much in Europe as it does in the U.S.

M. H. Trenker
Chairman, Dept. of Surgery
Medical School
Gdansk, Poland

Though your question pertains to Commodore computers, the answer is generally the same for all U.S. computer systems. It is possible to use a step-down transformer to achieve the proper operating voltage, but you need to be sure that you do get a high-quality transformer. The small "voltage converter" units available for running hair dryers and such are not an acceptable substitute. However, the transformer may not solve all the problems of using a U.S. system overseas.

The most significant hurdle is that Europe and North America use different video standards. Televisions and monitors generate video displays by repeatedly drawing a series of horizontal lines across the screen, one under the other. Computers using the European (PAL) standard generate a frame of 312 lines redrawn 50 times per second, while those using the North American (NTSC) standard produce a frame of 262 lines redrawn 60 times per second. The Commodore 64 and 128 handle scan-line differences by providing two different versions of the VIC-II video chip—one for NTSC and one for PAL. The drawing rate is determined by an internal quartz crystal, with different crystal frequencies used for NTSC and PAL systems. While we have no direct experience with the situation, it is our understanding that a complete U.S. system—with both the computer and monitor designed for NTSC—should work in Europe if provided with the proper operating voltage. However, it is not possible to intermix U.S. and European equipment. You can't hook a European (PAL) monitor or television to a U.S. (NTSC) computer, or a PAL computer to a NTSC monitor or television.

Disk drives are another area of confusion. Like that of the computer, the internal operating frequency of a Commodore drive is determined by a quartz crystal, and thus should not be affected by international variations in power-line frequency. However, the speed of the motor which spins the disk may be affected. The older 1541 disk drives have a speed adjustment and a strobe pattern on the drive flywheel to allow adjustment for either 60-hertz (North American) power-line frequency or the 50 hertz used in most of Europe. The 1571 drives we have seen lack this adjustment, but it may not be necessary because the 1571 uses a more sophisticated type of motor.

Unless you plan to travel frequently between the U.S. and Europe, you may find it simpler to purchase equipment designed specifically for the environment where it will be used. We'd be interested in hearing about the experiences of any readers who have attempted to use their computers overseas.