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1541 Alignment and Cleaning Guide

I've retained the original formatting so you may have to adjust it to get the file to display and/or print correctly. Noisy phone lines caused the occasional glitch or truncated file. I replaced some, but not all, instances of line noise with "[ERROR]" where applicable.

     A  1 5 4 1   A L I G N M E N T   A N D   C L E A N I N G   G U I D E

The cleaning and aligning of a 1541 disk drive is not an extrememly difficult process. A little mechanical ability and patience will usually be all that is required unless the 'sick' drive has some major problems.
Please note...This operation presents danger of electrical shock.
Extreme care is required....Always start with a clean-well lit work area.

The following tools are required:
1. phillips-head screwdriver...select one which fits the screw heads well to avoid stripping the screws.
2. Q-tips and alcohol (tape head cleaner words well also.)
3 light oil such as mystery oil or gun oil.
4. a long pair of tweezers is helpful in picking up those 'dropped' screws in hard to reach places.

Enter the following program and save it before proceeding to disassemble the drive:

100 OPEN1,8,15:OPEN4,8,4,"#"
110 FT=1:FT$=STR$(1):LT=35
120 LT$=STR$(LT)
130 PRINT#1,"U1:";4;0;LT;0
140 T$=LT$:GOSUB500
150 PRINT#1,"U1:";4;0;FT;0
160 T$=FT$:GOSUB500
170 LT=LT-1:IFLT>0THEN120
180 CLOSE4:CLOSE1:END
500 PRINT"READING TRACK:";T$
510 INPUT#1,EN,EM$,ET,ES
520 PRINTTAB(12)EN;EM$;ET;ES
530 IFEN<2THENRETURN
540 PRINT:PRINT"DRIVE HAS FAILED"
550 GOTO 180

Begin by unplugging the drive. Turn it upside-down and remove the four phillips head screws which hold the outer case together. Turn it rightside-up and remove the top half of the case. Next remove the metal cover over the printed circuit board.
In order to access the drive end stop for adjustment, remove the screws holding down the p.c. board and tilt the board to one side. If nesessary, disconnect the wires for the disk drive front green light but leave all other wire connectors in place. 
Use paper or cardboard to insulate the bottom of the circuit board from the drive frame. It is very important to be sure no part of the circuit board contacts the metal frame as this could 'short out' the components on the circuit board and cause extreme damage to the drive unit.
Now locate the drive read/write head. The head is very similar in function to a tape recorder head and is prone to malfunction due to excessive buildup of dirt, dust, and oxides from the disk surfaces. Use a Q-tip wetted with alcohol or tape head cleaner to gently wipe the surface of the head. Never clean the head with an abrasive substance or use strong solvent chemicals such as acetone.         The drive read/write head is a moveable unit which travels on two metal rails. These rails are prone to collect buildup of dust and grime and should be wiped with alcohol and lightly lubricated. Lubrication of any parts inside the drive    should be very light as the presence of excess oil in the drive unit can con    taminate the disks and/or cause dirt and dust accumulation on oily surfaces        One way to add a small amount of lubricant is to use a toothpick to place small droplets of oil. Dip the toothpick lightly in the oil, then touching the toothpick to the desired area allow a small droplet of oil to flow.
Another place that oiling may help is the drive motor. Remove the black 'dot' sticker on the top side of the drive motor and place one small droplet of oil onto the drive shaft.
After having cleaned and oiled the drive unit, the drive should now be checked for proper operation. Withe the p.c. board insulated plug the drive into the voltage source and the computer and run the prviously saved program. If the drive unit is still inoperative, error messages will appear and the alignment should be performed.

To begin the alignment, unplug the drive. Loosen the end-stop screw with a well-fitting phillips screwdriver, then re-tighten the screw just enough to firmly hold the end-stop in place.
Plug in the drive unit and run the test program. Use either the disk that came with the drive or a disk know to be created on a well aligned drive to test. If the drive fails, unplug the drive and lightly rap the end-stop withe enough force to move it slightly.
Exactly how much the end-stop should be moved and in what direvtion is a trial-and-error process. In general, the stop should only be moved a slight amount and can be moved in four directions. Patience is the most important ingredient as many attempts may be mesessary.
Try running the test on several disks. When (or if) the drive seems to be passing the test ok without error report, tighten the end stop screw. If however, the drive consistently fails the test after many tries, it may be in need of a mor 'major' alignment which reequires further disassembly of the drive and adjustment of the stepping motor.
If the previously explained alignment technique has failed, disassemble the drive unit and frame assembly, stand the drive unit on its side and scribe marks to indicate the stepping motor origional position. Loosen the three screws holding the stepping motor and move the motor small amounts in either direction testing the drive withe the test program. Alternate between adjusting the end-stop screw, pulley and shafts, or cam-pulley and shafts, or cam-pulley to shaft fits.
Nail polish or superglue may do the trick but a more professional compound such as loc-tite or a liquid fastener glue available at an electronic supply store may work better.

Another point to check is the drive motor speed. It is possible to check the speed using a very simple homemade timing light. An ordinary household 'nite-lite' works well. Aquire a nite-lite which employs a small neon bulb, (the type which glow orange), and remove the top or cover of the light. Plug the light into and extention cord.
To use the timing light, plug the light in and withe the drive unit disassembled enter a disk command which will turn the motor on such as newing a disk. Hold the light near the flywheel and observe the outer set of timing marks. They should appear stationary and may be adjusted to appear stationary by the drive motor speed control adjustment on the small p.c. board located on the drive unit bottom side.
     NOTE: The inner set of timing marks are for use with 50hz power sources. 60 hz is emplyed in the U.S.

With a little lluck and a lot of patience, the 'sick' drive may be restored to a healthy state, but if all else fails be aware that Commodore will replace the defective drive unit with a new or re-built drive for only $85.00. The drive can be in most any condition and need not be still under warranty. Just mail it to Commodore with a check for $85 and expect a 6-8 week wait for return. 
The same policy applies to the C-64 for $55.00 and to the Vic-20 for $35.00

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Intro
Ailanthus Tree: Login | Users | Commands | Messages | Chat | Hang
Magpie BBS: Messages | Users | Commands
Misc BBSes: Aerogram | Bonsai Tree | Mofo | NYCENET | Riverdale | Misc Messages
ASCII Art: Nude | Jane | Femme | Spock | Kirk | Nixon
Game Docs: Archon II | Breakdance | Bruce Lee | Cutthroats | Dallas Quest | Deadline | Flight Sim 2
Hitchhikers Guide | Incredible Hulk | Infidel | Kennedy Approach | Mask of the Sun | M.U.L.E.
Pastfinder | Pinball Construction Set | Raid on Bungeling Bay | Raid over Moscow | Rescue on Fractalus
Seven Cities of Gold | Sonar Search | Spy vs Spy | Whistler's Brother
Util Docs: Blitz Compiler | Designer's Pencil | Easy Script | Kwik-Write | Micromon
Movie Maker | Paperclip | Perspectives | Wordpro 3 Plus/64 | Wolfenstein
Philes: 1541 Alignment | 976 Numbers | Mainframes | Sysops' Bible
Drugs | Knock-Out Drops | Lock Picking | Radar Jamming | Thermite


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Last modified: Fri 02 February 2007 13:23:45