Check the listing for details. 1050 DIAGNOSTIC DISK CPS 800/XL/XE/1050 Atari NEW Atari FD100690. Condition: New. Listed at 19.95 USD. Original brand new Atari CPS 1050 Diagnostic Disk FD100690 for 8-bit Atari 800/XL/XE/1050/ETC. These are brand new and originals from Atari. We use these to test every 1050 Disk Drive we sell or repair. It includes both diagnostic and alignment procedures. We find and correct problems with clock adjustment, track zero sensor, drive alignment, temperature sensitivity, ETC using this diagnostic. To do Alignment you also need an Analog Alignment Disk and an O-Scope. We sell the Alignment Disk on Ebay soon. ALIGN DISK 5.25 OSCOPE Dymek DK 592-11 To do Alignment the best results are with a differential O-scope connected to pins TP1 and TP2 or TP3 and TP4. TP17 is ground if you use single sided in instead of differential input. You balance the Catseye to align the disk drive. This is standard disk drive alignment. See this link. http://www.myatari.com/dymekalign.pdf SORRY WE SOLD OUT OF THESE NOTE: The Atari CPS 1050 Diagnostic Disk FD100690 only work with stock Atari Original 1050 Disk Drives. They do not work on a 1050 with a Happy or a Chip or a US Doubler or any other drive upgrade. They do not work on a Atari 810, Rana, Track, Percom, Indus or any other non Atari 1050 drive.Click here to review my terms & conditions."If you do not understand something about an auction then PLEASEcontact us and get an answer you understand before purchasing. EBAY NOW CHARGES FEES ON SHIPPING AND HANDLING.WHEN YOU BUY MULTIPLE ITEMS AND PAY BEFORE WE SEND A COMBINED INVOICE YOU MAY PAY A LOT OF EXTRA SHIPPING."