NOTE: All 1540 Disk Drives were manufactured prior to any changes to the board and
used the Alps drive exclusively.
1541 MODEL IDENTIFICATION
PCB Assy # 1540008-01
PCB Assy # 1 540048
-01
-03
Schematic # 1540001
Original "Long" Board
Has 4 discreet 2114 RAMs
ALPS Drive only
Schematic # 1540049
Referred to as the CR board
Changed to 2048 x 8 bit RAM pkg.
A 40 pin Gate Array is used
Alps Drive
Newtronics Drive
PCB Assy # 250442-01
PCB Assy # 250446-01
Schematic # 251748
Termed the 1541 A
Just one jumper change to accommodate both types of drive
Schematic # 251748 (See Notes)
Termed the 1541 A-2
Just one jumper change to accommodate both types of drive
NOTE: The simplest way to identify which drive you have is by the door assembly. Alps is made
with a "push down" door and Newtronics has a "flipper" type door.
DEVICE NUMBER CHANGE
The 1540 and 1541 drives are shipped from the factory set for device # 8. The channel can be hard
ware altered to # 9, 10, or 11 by two methods:
1) Refer to appropriate board layout drawing for the location of the pads provided for
this purpose. The device change pads must be CUT to alter the channel number and re-soldered if
another change is needed later.
2) The preferred method to alter the device number is to lift certain pins of the 6522
chip. The I.C. should always be socketed, so removal of the chip is simple. Once removed, the proper
pin can be carefully bent to eliminate it from the circuit. If another change is needed, simply remove
the I.C. and re-install with the pin back in place.
PCB ASSY #
LOCATION
DEVICE # LIFT PIN
1540008
UAB1 9 15
1540048,251748
UC3 10
16
and 251834 UC3
11
15 and 16
21
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