DIAGNOSING DISK-DRIVE PROBLEMS by Mark Witt, COG, June 1987 (A basic look at common disk drive problems) One of the most disconcerting malfunctions on any microcomputer is trouble with disk drives. Not only can drive failure result in down time, but it can cause irreparable damage to your data and program files. The symptoms of drive malfunction are files that won't load, disk write errors, files that contain unexpected information, diskettes that suddenly won't boot and program crashes. Very often the drive will read reliably but include garbage data when writing to a diskette. This is bad enough when the garbage is written into Wordstar text, but the entire diskette can be lost if it occurs in the directory area. These symptoms will be aggravated by a warm or hot machine. Do not subject difficult-to-replace data to suspect drives. Four disk drive problems are commonly encountered. We will begin with the most likely and move to the least likely. DIRTY HEADS The best defence here is a good offense. CLEAN YOUR DISK DRIVE HEADS! Purchase a head cleaning kit and keep it handy. The kit will contain easy-to-follow instructions and information about frequency of cleaning. Dirty heads are not a possible future problem, they're a future certainty. All disk drives in use will get dirty. Not heeding this warning will leave you some Sunday afternoon with an unusable computer and no place to get the kit. If you've had problems and tried cleaning your drive heads and found little or no improvement, do it again. The instructions with the kit will indicate ten- to thirty-second cleanings, but that assumes no buildup. If you have been using your computer for two or three months, you must remove the accumulation. You may purchase a dry type, but I prefer the wet/dry type. With this method you receive one or two diskette-like devices. They differ from diskettes in that the media has been replaced with a cloth-like material. You apply an alcohol solution to the material and boot the system. The monitor will display "BOOT ERROR" messages. After the time required by the instructions, press Reset and place the freshly wetted diskette in drive B. Instead of RETURN, press SHIFT and the double-quote key to boot the system from the B drive. Again "BOOT ERROR" messages will be displayed. When finished cleaning the heads, mark the date on the head- cleaner package so you will know when you are due again. Some head cleaners are less abrasive than others; read the instructions. You may be surprised to learn that many head- cleaning systems meet the ANSI abrasive standards for diskettes. ALIGNMENT AND SPEED A second problem is alignment and/or speed. When the drive is new, the data pattern is written and read in a specified way and at a specified speed (300 rpm). As machines age or are dropped, the pattern and speed can get out of whack. An alignment and speed adjustment to correct this can be done by any computer repair shop. It is a good idea to check around for prices, which can vary greatly. HARDWARE FAILURE Hardware failure is an unlikely culprit, but the most expensive to remedy. The chain of events that lead to information being written or read begins with the mother board, in a chip called the drive controller. If this is defective, the board should be replaced. Next, if you have double density, is the double-density board. problems with this will sometimes cause your machine to work perfectly in double density but fail to write single density. Adjustment or replacement of the double-density board is in order. See your dealer. Next, the data is routed through the drive cable to one drive or the other. The cable must be seated firmly on the connections with the connector right-side-up. Failure here can be caused by pinching the cable between the case halves (grey case) or pinching other components and severing a wire, Sometimes a screw is driven into the cable during reassembly. Replacing a severed or broken cable is the solution. The next point for the data to flow is the PC board, on the top side of the drive. Failure of this board cannot usually be diagnosed by your dealer, and the entire drive would be sent to a repair firm for exchange. The last point of handling is the drive itself, where the data is written or read in much the same way music is written to a tape in a tape recorder. None of these components should take more than an hour to replace. EXCHANGED PARTS Most dealers use exchange parts. You get a used computer part that has been upgraded and tested in exchange for your old part and a fee. The cost is sometimes as little as on tenth of the cost of a new part. Ask your dealer whether the price you have been quoted is an exchange price. Try to get an exchange price. If not, you have a right to the old parts. Get them and keep them, as they might come in handy. POWER PROBLEMS If the drive problem refuses to show up when the computer is at the dealer's or moved to another location, suspect the power coming into your home or office. This is the fourth common cause of drive problems. In some cases, voltage may be too high for the computer to operate properly. The problem is that the computers were designed in California, where the base line of the voltage is 110 volts. Acceptable voltages there are 103 to 117. In Chicago, the base line is 120 volts. Your power will vary between 113 and 127. Getting in the higher ranges will cause disk-write errors, screen garbage, internal Wordstar errors and unpredictable behavior. SURGE PROTECTORS WON'T HELP These warning signs will show more as the machine warms. Most surge protectors won't solve the problem because the "clamp" at high levels where physical damage could occur to the computer, not at levels interfering with operation. Check the voltage several times with a voltmeter. If it is 125+ consistently, it may occasionally go over 127. You can call the electric company and report that the voltage is on the high side and needs adjustment. Expect the company to refuse to do anything. If this happens, ask to speak to a manager. If no action is promised, request the number of the ICC. Call the ICC, and either the ICC or the power company will come to your home and put a five-day recording voltage checker on the line. Neither party should charge for this service the first time. If it is the electric company that puts the checker on the line, rest assured that it will have corrected the problem before workers come to your home.