Apple Disk II Technical Procedures

SYMPTOM IC LOCATIONHead does not move 2003 D4Disk does not turn 2003 D4Recalibrates repeatedly 3470BlI/O ERROR 347 0 Bl3146 A374LS125 B4" " 2003 D4If you have replaced all of the ICs on the analog card andthe catalog still does not display, perform the COMPARATOROFFSET ADJUSTMENT located in the calibration procedures ofthe Disk ][ Technical Procedures section. If the analog cardstill fails to function properly, place all original ICs intheir sockets and return the card to Apple.Drive Has Trouble WritingIf the analog card correctly displays the catalog of drive 2,perform the following steps:1. Boot the DOS 3.3 System Master diskette in drive l, andthen move it to drive 2.2. Type CATALOG,D2 and press . The catalog will bedisplayed on the video screen. Files displayed with anasterisk (*) preceding the filename are locked and maynot be deleted. Note that filename HELLO is preceded byan asterisk.3. Type UNLOCK HELLO and press .4. Type CATALOG,D2 and press . The catalog will bedisplayed on the video screen. Verify that filenameHELLO is not preceeded by an asterisk. If you encountertrouble when attempting to unlock the file, turn off thepower to the computer and replace the following devices(except those which have been replaced previously), oneat a time, repeating this test after each device untilthe UNLOCK command executes successfully:- IC at B4 (labelled 74LS125)- IC at D4 (labelled 2003)- IC at A3 (labelled 3146)Disk ][ Analog Card rev Jun 84 Page 5.11