Shareware Grab Bag

home *** CD-ROM | disk | FTP | other *** search

/ Shareware Grab Bag / Shareware Grab Bag.iso / 011 / align.arc / ALIGN.DOC next >

Wrap

Text File | 1985-07-19 | 20.6 KB | 591 lines

ALIGN Version 1.6 for the IBM PC 5/23/84 (c) Copyright John L. Dickinson 1983, 1984 COPYING PROVISIONS This program and documentation may be freely copied and shared provided it is not modified in any manner and this notice is not bypassed or removed. Please keep the ALIGN.DOC documentation file on the same diskette with ALIGN.EXE. If you find the ALIGN program useful, a contribution will be appreciated. ($20 suggested.) Comments or suggestions concerning ALIGN are welcome at any time. John L. Dickinson 2470 N. Tierra Verde Pl. Tucson, Arizona 85749 PROGRAM OVERVIEW The ALIGN program allows you to move a diskette drive head to absolute track locations and operate the drive while checks and adjustments are made. 40 track single or double-sided drives are supported. ALIGN is one of several tools needed to adjust and service diskette drives. The ALIGN program does not attempt to teach you how to do an alignment, but it isn't difficult if you have what you need. In addition to this program, you should have: The drive manufacturer's alignment and service procedures. An oscilloscope (dual trace with triggered sweep). A DYSAN double-sided analog alignment diskette for 40 track drives, 224/2A #800180. Extension or external diskette drive signal and power cables are very helpful. See the notes at the end of this document for possible sources for these items. An analog alignment diskette contains NO data, just special waveforms and can't be copied. (It's really copy protected!) You can try the program using any diskette. The ALIGN program does not write on diskettes. (It should also be possible to use this program to adjust 80 track drives provided you have the proper alignment diskette. However, some of the program commands may not be useful since they have track addresses hard coded for the 40 track alignment diskette.) ALIGN Version 1.6 Page 2 SYSTEM AND DISKETTE DRIVE REQUIREMENTS ALIGN runs under IBM PC-DOS on a PC or PC/XT with at least 64K and an 80 column display, either monochrome or color. Since ALIGN uses standard BIOS interfaces for all I/O, it should also work on most IBM compatibles. It does not work properly on the PCjr. The diskette drives to be adjusted are connected to the PC in the usual manner. The ALIGN program works with standard IBM (Tandon) diskette drives and should work with others that use the same electrical interface. USING THE ALIGN PROGRAM Enter ALIGN after the DOS prompt and press any key to get past the initial screen to the main command menu. Chances are, you'll be able to use the program without reading any more of this documentation. Commands are entered one at a time on the command line. All commands may be abbreviated and the first letter is sufficient for all but one command. (INFO requires the 3 letters, INF.) Some commands require one operand as listed on the menu. Numeric operands, such as track number or seconds, are decimal. The first track is track 0, not track 1. If the diskette drive under test is running, pressing any key will cause it to stop in about 2 seconds. This key may be the first letter of the next command or any key such as the RETURN key. The drive will stop by itself after 60 seconds. If the drive is stopped and and you want to continue the previous motion command, simply press the RETURN key. This enters a null command which is interpreted just like a GO command. Commonly used commands may also be entered using the program function keys as shown on the command menu. ALIGN Version 1.6 Page 3 ALIGN PROGRAM COMMANDS DRIVE A..D The DRIVE command specifies the letter of the drive under test: A, B, C or D. The default is drive B. The DRIVE command does not cause the drive to start. Examples: DRIVE A (Set drive A) D C (Set drive C) HEAD 0..1 The HEAD command selects the lower or upper head (diskette side). HEAD 0 is the lower head and the only head on a single- sided drive. HEAD 1 specifies the upper head on a double-sided drive. The HEAD command does not cause the drive to start. Examples: HEAD 0 (Set head 0, the lower head) HEAD 1 (Set head 1, the upper head) H 1 (Set head 1, the upper head) TRACK 0..39 The TRACK command moves the head to a specified track and starts drive motion. The drive will continue to run until a key is pressed or for 60 seconds. (The 60 second run time may be changed using the SECONDS command.) The track number that may be specified is usually in the range 0 through 39, although the upper track limit may be extended using the MAX command. Examples: TRACK 0 (Move to track 0 and run drive) T 34 (Move to track 34 and run drive) T 16 (Move to track 16 and run drive) IN OUT The IN command moves the head to track 32 and then immediately moves it "in" towards track 0 stopping on track 16. IN is equivalent to the TRACK 32 command followed by TRACK 16. The OUT command is similar, but moves the head first to track 0 and then "out", away from track 0 stopping on track 16. OUT is equivalent to a TRACK 0 command followed by TRACK 16. Both commands end up on track 16 with the drive running. Track 16 is the radial head alignment track on the Dysan 40 track alignment diskette. ALIGN Version 1.6 Page 4 After making a head adjustment it's a good idea to re-seek to track 16 and check the cat's eye pattern again. Both the IN and OUT commands cause a re-seek to track 16. The two commands also allow checking the accuracy of seeks (and the resulting head alignment) in both directions. If there is a difference in the cat's eye patterns in the two directions, you may want to re-adjust the alignment to split the difference. A difference indicates play in the mechanism or an imprecise head stepper motor. GO If the drive is stopped, the GO command simply starts the drive at whatever track it happens to be on. A null entry does the same thing, so you can just press the RETURN key with nothing on the command line to start the drive. SECONDS 3..180 Normally, each time you start the drive using ALIGN, the drive runs for 60 seconds if not stopped by pressing any key. This is usually enough time to make a check or adjustment and prevents the drive from running "forever". The SECONDS command allows you to change this 60 second limit anywhere from 3 to 180 seconds. The SECONDS command does not cause the drive to start. Examples: SECONDS 120 (2 minutes) S 10 S 30 CYCLE The CYCLE command starts the drive and cycles the head through tracks 0 through 3 in the following order 3,2,1,0,3,2,1,0,3,2... and so on for the purpose of checking the track 0 switch. The drive changes tracks every few seconds so you have time to see if the track 0 switch has switched. In between each track (0,1,2 or 3) the CYCLE command moves the head to track 16 so there is a seek similar to that when a drive is first used after power-on. Believe it or not, on Tandon TM-100 series drives, the track 0 switch should switch between tracks 1 and 2. (It's NOT supposed to switch at track 0!) This is a position in the middle of the first four tracks. The actual track 0 signal on the drive interface is a combination of the track "0" switch and other indications in the drive electronics. Switch here | V 0 1 2 3 ALIGN Version 1.6 Page 5 While the CYCLE command is active, the PC's speaker sounds rapid beeps equal to the current track number, 1 to 3, each time it changes tracks. Track 0 is a single longer beep. These beeps allow you to know what track the drive is on without trying to watch a meter or test light and the PC's display at the same time. A higher pitch sounds in addition to the track beeps when the switch should switch. After a little practice, the sound eliminates the need to watch the screen. As you watch your meter or light, don't be confused by the very brief switch changes when the head moves out to track 16 and then back in. While it's always nice to set things "right on," the track 0 switch adjustment isn't critical and the drive operates fine even when it switches a whole track off from the ideal point between tracks 1 and 2. MAX 39..90 The MAX command sets the maximum track allowed with the TRACK command. Normally, the TRACK command accepts track numbers from 0 through 39. The MAX command allows you to change the TRACK command's high track limit all the way up to 90. The MAX command does not cause the drive to start. There really isn't much occasion to use the MAX command. It's most obvious use is to allow the ALIGN program to be used with 80 track drives. In this case you would specify MAX 79. (Note that the IN and OUT commands assume a 40 track alignment disk and won't be useful with an 80 track alignment disk. You can still use the TRACK command to do the equivalent manually.) Or, maybe you're looking for the track 39 signal on the DYSAN alignment disk. If it doesn't appear on what the system thinks is track 39, maybe it will show up at what the system thinks is track 40, or 41 or.... Actually, there is a limit to how far the head will go past track 39. You may want to use the MAX command to allow you to investigate just how much further the head will go. (A copy protection scheme might use one track past the "end" of the disk.) However, before you go charging off into the stratosphere of track addressing, realize that when the head hits the upper limit, it does so with the full force of the stepper motor. This alone could knock a drive out of alignment or possibly cause permanent damage. Use the MAX command at your own risk. ALIGN Version 1.6 Page 6 RESET The RESET command causes a reset of the diskette system (via BIOS INT 13 with AH=0). RESET does not cause the drive to start. The next time any drive is accessed, it will then be "recalibrated." This means that the diskette controller makes no assumptions about which track the head is on, moves the head until track 0 is located as indicated by the drive, and then proceeds with the requested operation. Once this recalibration process is complete, the diskette controller keeps it's own head position register and simply pulses the head forward or back, one step at a time to get to a desired track. If one pulse is missed or the head is moved manually with power-on, then the controller's track register won't agree with the physical position of the head. "Recalibration" is not an adjustment, but rather a normal operation done by the diskette controller so it can get in sync with the physical head position. Every drive is "calibrated" by the controller the first time you use it after power-on or boot. The RESET command allows you to recalibrate during the drive adjustment procedure. For instance, assume the the drive is on track 16 (or what you think is track 16). If you issue a RESET command and then simply start the drive motion (null entry), you will hear the drive move to track 0 and then back out to track 16 as the drive is recalibrated. The RESET command is useful when servicing drives and you think the drive is not seeking to the correct track. This could happen while adjusting the track 0 switch. Also, the drive won't seek to the correct track anytime the head has been moved against the stepper's electrical hold. This could occur when the head assembly hits it's travel limit at either end. This isn't normal operation, but when the adjustments are wrong it can (and does) happen. If you don't find an alignment disk signal where you think it should be, try the RESET command. It is also a good idea to use the RESET command just before the final checks on radial head alignment to be sure you're not exactly 1 or 2 tracks off. ALIGN does an automatic RESET between every CYCLE command seek to make track 0 switch adjustment easier. Without the RESET command, it would otherwise be necessary to re-boot or turn the machine off-and-on to force a recalibrate operation. ALIGN Version 1.6 Page 7 INFO The INFO command causes another screen to be displayed with a brief description of each track on the Dysan 40 track alignment disk. It's simply for reference. Pressing any key returns you to the ALIGN command menu screen. QUIT The QUIT command terminates the ALIGN program and returns to DOS. DRIVE SPEED TESTING ALIGN does not have the capability to check a drive's spindle speed. The IBM "Advanced Diagnostics" diskette that comes with the IBM Hardware and Maintenance and Service book provides a good software check of drive speed. Lacking that, use the ALIGN program to run the drive while you observe the strobe disk on the bottom of the drive. INSTANTANEOUS SPEED VARIATION TESTING To test Instantaneous Speed Variation, the Tandon manual says to first "write a 2F (all ones) pattern on any track." The ALIGN program won't write this or anything else on your diskettes. A totally satisfactory substitute is to simply use the DOS FORMAT command to format a work diskette in the drive under test. This puts a pattern on every track. Admittedly, it's not "all ones" but you'll hardly know the difference as you observe the pulse jitter on the oscilloscope. Also, while Tandon says to use "any" track, the jitter is much worse on the inside (high) tracks. Use a middle track, such as 16, to check the specification. Get to know what normal jitter looks like on tracks 0 and 39 too. ALIGN Version 1.6 Page 8 TANDON TM-100 SERIES REPAIR TIPS LOOSE SCREWS AND NUTS - HEAD MISALIGNMENT In my experience, the most frequent cause of head misalignment and drive failure on Tandon TM-100 series drives is a loose Allen head screw on the stepper motor shaft. This allows the motor shaft to slip where it connects to the split band positioner pulley. Tighten this Allen head screw before doing an alignment. It's not unusual to tighten it one-half turn holding the short end of an Allen wrench with just your fingers. Don't over-do it, however, as you could strip the threads. The stepper motor shaft is smooth and has no flats or keys. As long as you are doing an alignment and the Allen screw is tight, the exact pulley position on the shaft usually doesn't matter. But sometimes it can be out of the head alignment cam screw adjuster range. If this happens, loosen the Allen screw, rotate the pulley a bit, tighten it, and try again. While you're at it, check the two nuts that hold the track stepper motor to the casting. Also, remove the clear plastic cover on the bottom of the head assembly and carefully tighten the little Phillips screw that holds the split band on the pulley. If you're not going to do an alignment, don't tighten these screws since just tightening them might change the alignment some. TRACK 00 SWITCH PROBLEMS - BOOT FAILURE The track 0 microswitch frequently becomes intermittent or fails. You can easily check this by powering-off the system and removing plug 11 on the back of the drive. Push a few pieces of bare wire into the connector and check the switch contacts with an analog ohm meter. The switch is single pole, double throw (SPDT). | | | | | | <- wires to switch ------------ | | COM - common center contact | Plug | NC - normally closed | | NO - normally open | | Pin # -> |4 3 2 1| ------------ COM NC NO <- Switch contacts Operate the switch manually. It is a little hard to get to and you may want to remove the logic board first. Check to see that contact closure is positive, occurs when the switch clicks, and without any wavering around. If the switch is not operating properly, the problem is usually just a very small amount of corrosion or oxidation on the switch contacts. Rather than replacing the switch, the easy and ALIGN Version 1.6 Page 9 effective repair is to pass some reasonable current through the switch and operate the switch a few times. Be sure that plug 11 is disconnected from the logic board and that you make connections to just the plug. Use an external CURRENT LIMITED low voltage supply to burn off the little bit of oxidation. I don't know how much current to recommend. I use just enough to cause a little spark when the power supply leads are touched, probably 0.5 or 1.0 amp. Be sure to use a current limited supply or put an appropriate current limiting resistor in series. If you don't know how to do this, then find someone who does rather than risk any harm or damage. POSSIBLE SOURCES FOR SUPPLIES For the type of drives usually used in the PC, the alignment and service procedures are in the Tandon "OEM Operating and Service Manual TM-100-1 and -2 Disk Drives, 48 Tracks per Inch." Priority One Electronics sells this as part number 07TND179022001, for $36.00. Priority One Electronics 9161 Deering Ave. Chatsworth, CA 91311 Telephone (800) 423-5922 (818) 709-5111 It is also Tandon part number 179022-001, listed at $25.00 on a December 1982 Tandon price list. I don't know if they will sell it directly to end users. Tandon Corporation 20320 Prairie Street Chatsworth, CA 91311 Telephone (213) 993-6644 Analog Alignment Diskettes (AAD's) are available directly from Dysan Corporation. 5.25" Double-sided, 48 TPI, 224/2A #800180 $50.00 5.25" Single-sided, 48 TPI, (numbers not known), $25.00 (96 TPI alignment diskettes are also available.) Dysan Corporation 5201 Patrick Henry Drive Santa Clara, CA 95050 Telephone (800) 551-9000, Dept 50 (408) 988-3472 Extension or external diskette drive signal and power cables may be difficult to locate or you may have to make your own. Priority One carries everything you need for the signal cable but not the power cable. (If you know of a source for the male and female power connectors in small quantities, please let me know.)