NOTICE: This article originally appeared in the October, '88 issue of MichiganAtari Magazine and may be freely distributed or reprinted in non-profit UserGroup publications as long as the article's author and Michigan Atari Magazineare credited AND this notice is reprinted with the article. All otherpublications must obtain written permission from Unicorn Publications, 3487Braeburn Circle, Ann Arbor, MI 48108, Phone: (313) 973-8825 before using thisarticle. To obtain the figures described in this article, simply send aself-address, stamped envelope to the above address.XF551 Power LED OptionHardware modification by David Bryant (GKAUG)Several Atari users have already seen the new XF551 disk drive, and enjoy thedouble density, double sided features. It seems that one feature on both the810 and 1050 drives was left out. The new XF551 does not have a Power LED tolet you know the drive is on. If your drive reacts like mine, the disk accessLED lights up when you turn the drive on and also when you turn the drive off.This project will help resolve that oversight by installing a power LED in thefront panel, below the disk access led.Warning: this modification requires that you remove the covers and modify thefront panel, so it will void any warranty from Atari Corporation.Parts Needed:1 - RED LED, Radio Shack #276-018.1 - 100 OHM RESISTOR, RS #271-1311.1 - LED Holders, RS #276-079.2 - 14 inches, 24 Gage Wire.Instructions:1: Turn the drive upside down and remove the four phillips screws that securethe top. Now remove the top.2: Locate the power cable (it has four wires and is keyed) that plugs into therear of the drive, and unplug it.3: Also locate the data ribbon cable (it is also keyed) and unplug it.4: Use a pencil and draw a line on the bottom case below the disk access led.5: Remove the four phillips screws that attach the disk drive mountingbrackets to the bottom case. Now lift the drive assembly from the bottom caseand set it aside.6: Use care and drill a 1/4" hole in the vertical edge, of the bottom case,where you drew the line in step #4. (See diagram #1)7: Insert one Led Holder in the hole.8: Locate the jumper wire marked "V" on the front edge of the interfaceprinted circuit board. (See diagram #2) Solder one of the 14 inch wires to it.Solder the other end of this wire to the ANODE end (long leg) of the LED.9: Locate the jumper wire marked "G" on the front edge of the interfaceprinted circuit board and solder one leg of the resistor to it (See diagram#2). Solder one of the 14 inch wires to the other leg of the resistor. Pressthe resistor flat against the PCB. Solder the other end of this wire to theCATHODE end (short leg) of the LED.10: Insert the LED into the led holder and press the legs flat against thebottom case. Route the wires along the left edge, between the drive supports.11: Plug in the power cable to the back of the disk drive and turn on thepower switch. The power led should light. If not, then check your wiring orthe polarity of the led.12: If all works well, then remove power and reattach the Drive to the bottomcase. Attach the two cables removed in steps #2 and #3. Now install the topcase to the bottom case.13: Apply power and check again for proper operation. David Bryant is a devoted Atari 8bit user, Treasurer of GKAUG, and may becontacted at the club's BBS (616-657-2665).
