Service manual

Appendix A Test Equipment
FileStore Service Manual 112
 SCSI interface - write IRQ enable 1 (‗1‘): pin 11 of IC10 should be as seen in Fig 10 (and
not stuck either high or low). Pin 9 of Icl0 should now be logic 1.
 SCSI interface - SEL/BSY handshaking (‗H‘): the result 2 should be printed. If nothing
happens then there is either a loose connection or a fault in the disc controller board. The
handshake operates during data transfer. If the hardware for this handshake is faulty, there
can be no data transfer.
FileStore E01S
 Printer test - the printer port pin corresponding to the bit number that was selected should
show a square wave. All other pins should show flat signals.
 SCSI interface - read data (‗R‘): pin 1 of IC37 should be as shown in Fig 10 (and not
stuck either high or low).
 SCSI interface - write data (‗W‘): pin 11 of IC38 should be as shown in Fig 10 (and not
stuck either high or low).
 SCSI interface - read status (‗?‘): pin 1 of IC36 should be as seen in Fig 10 (and not stuck
either high or low).
 SCSI interface - write select (‗S‘): pin 11 of IC33 should be as seen in Fig 10 (and not
stuck either high or low).
 SCSI interface - write IRQ enabled 0 (‗0‘): pin 11 of IC34 should be as seen in Fig 10
(and not stuck either high or low). Pin 9 of IC10 should now be logic 1.
 SCSI interface - write IRQ enable 1 (‗1‘): pin 11 of IC34 should be as seen in Fig 10 (and
not stuck either high or low). Pin 9 of IC10 should now be logic 1.
 SCSI interface - SEL/BSY handshaking (‗H‘): the result 2 should be printed. If nothing
happens then there is either a loose connection or a fault in the disc controller board. The
handshake operates during data transfer. If the hardware for this handshake is faulty there
can be no data transfer.
Figure 10: Example waveform