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NOTE: All 1540 Disk Drives were manufactured prior to any changes to the board and used the Alps drive exclusively.


PCB Assy # 1540008-01
  • Schematic # 1540001
  • Original "Long" Board
  • Has 4 discreet 2114 RAMs
  • ALPS Drive only
PCB Assy # 1540048
  • 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 (-01)
  • Newtronics Drive (-03)
PCB Assy # 250442-01
  • Schematic # 251748
  • Termed the 1541 A
  • Just one jumper change to accommodate both types of drive
PCB Assy # 250446-01
  • 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 door assembly. Alps is made with a "push down" door and Newtronics has a "flipper" type door.


The 1540 and 1541 drives are shipped from the factory se for device # 8. The channel can be hardware 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.

1540008 UAB1915
1540048,251748 UC31016
and 251834 UC31115 and 16

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This page has been created by Sami Rautiainen.
Read the small print. Last updated September 05, 2020.