Acorn Computers Limited Winchester disk 110, Service Manual, Page: 8 / 43

3. Specification
The Winchester Disc unit provides storage and retrieval of data and programs
on non-removable magnetic discs. This can be local storage for a
microcomputer such as the BBC Microcomputer model B or as a fileserver for an
ACORN ECONET local area network.
The Winchester Disc unit consists of a 10 Mbyte (model 110) or 30 Mbyte (
model 130) hard disc drive, an ADAPTEC ACB-4000 Winchester Disc Controller,
an Acorn Host Adapter Board which is an interface between the ACB-4000 and the
host computer's 1 MHz expansion bus, and a power supply unit. The unit also
contains a 240V AC fan for cooling.
3.1 Disc drive
Capacity 10M (model 110) or 30M (model 130) formatted
Format ADAPTEC 33 sectors of 256 bytes
Cylinders 306 (10M version)
Heads 4 (10M version)
Disc rpm 3600
3.2 ADAPTEC ACB-4000 Winchester disc controller
Disc interface ST-412
Host interface SCSI
3.3 Host Adapter
SCSI to 1 MHz expansion bus
3.4 Power supply
Minimum input voltage 198V AC
Maximum input voltage 264V AC
Supply frequency 47 to 53Hz
+5V output voltage 4.9 to 5.2V
+5V output current 0.7 to 3.5A
+5V overvoltage protection 5.8 to 7.0V
+5V overcurrent protection 5.0A
+12V output voltage 11.4 to 12.6V
+12V output current 0.6 to 3.0A
+12V surge output current 5A for 15 seconds
+12V overvoltage protection 13.0 to 16.0V
+12V overcurrent protection 6.0A
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