The 2/10 drive cage cabling supports a parallel port hard disk and 3.5" floppy drive, while the earlier models have two cables for floppy drives -- The 1/5 & 2/5 chassis ribbon cable is different from the 2/10 chassis ribbon cable.
This difference means that one cannot directly substitute a 2/10 motherboard for a 1/5 aka 2/5 motherboard. Mismatching the cabling and motherboard can result in damage.
Shown below is one variant of a "universal" Lisa Chassis Ribbon Cable Assembly.
With the appropriate parts, it can be connected as a 1/5, 2/5, or 2/10.
Pin 1 of the 60 contact card edge socket is aligned with the red stripe on the left.
1/5 Configuration
The first 26 conductors are connected to a 26 pin socket header for connection to the upper Twiggy drive. This connector is reversed on the cable, so pin 26 of the connector is where the red stripe is and connected to pin 1 of the card edge.
The next 26 conductors are connected to a 26 pin socket header for connection to the lower Twiggy drive. This connector is oriented as the upper one, with pin 26 of the connector connected to pin 27 of the card edge.
The last 8 conductors are connected to pins 1-8 of a 10 pin socket header for connection to the power button/keyboard jack assembly. Pin 1 of the socket is connected to pin 53 of the card edge.
2/5 Configuration
The first 26 conductors are unused
The next 26 conductors are connected to a 26 pin socket header for connection to the Lite Adapter. This connector is oriented with pin 26 of the connector connected to pin 27 of the card edge (same as for use with a lower Twiggy drive)
The last 8 conductors are connected to pins 1-8 of a 10 pin socket header for connection to the power button/keyboard jack assembly. Pin 1 of the socket is connected to pin 53 of the card edge.
2/10 Configuration
The first 6 conductors are unused
The next 20 conductors are connected to a 20 pin socket header for connection to the 3.5" floppy drive. This connector is oriented so pin 1 of the connector is connected to pin 7 of the card edge.
The next 25/26 conductors are connected:
- a 26 pin socket header for connection to the Widget parallel port. This connector is oriented so pin 1 of the connector is connected to pin 27 of the card edge.
Note this is NOT the same as the orientation of the lower Twiggy/Lite Adapter connector!
Optional (not Apple original):
- a DB25 socket for connection to an external ProFile. This connector is oriented so pin 1 of the connector is connected to pin 27 of the card edge.
(In the picture, conductors 22-24 (of these 26) have a twist to swap the positions of pins 23 and 25 of the DB25; but I think this is not required or typical)
The last 8 conductors are connected to pins 1-8 of a 10 pin socket header for connection to the power button/keyboard jack assembly. Pin 1 of the socket is connected to pin 53 of the card edge.
Edit: added emphasis that the 2/10 parallel port connector and the lower Twiggy/Lite Adapter connector are not the same orientation.
Quote from: sigma7 on May 24, 2024, 06:47:58 PM
... making/modifying your own.
The difficult end of the ribbon cable is a Card Edge Connector With Flanges, 60 contact, 0.1" (2.54mm) spacing, 1/16" (1.59mm) board thickness - IDC Termination for ribbon cable
Sample part numbers:
3M: 3666-0000 (holes in flanges), or 3666-0002 (slotted flanges)
This part is long obsolete and currently appears unavailable new from any manufacturer. Some NOS resellers in Hong Kong list it as available, but line/order minimums are likely to make them an expensive option.
You may want to resort to stripping and soldering 60 ribbon cable conductors to a solder lug or other style of card edge connector.
Otherwise, if a suitable adapter is not available, one option may be to use a wire-wrap card edge connector and use IDC socket headers to plug onto the wire-wrap leads. Note that the arrangement of pins on the bottom of the connector are the mirror image of the usual header arrangement; one can deal with this reversal by using (one row of each of) two 60 pin IDC sockets, or if they are long enough, bending each pair of wire-wrap pins to swap the row orientation.
There may be easier/cheaper ways to deal with this unavailable connector -- please post your ideas!
Ribbon Cable, 60 conductor, stranded, 0.050" (1.27mm) pitch
This can be composed of eg. two 26 and one 8 conductor ribbons.
The original 1/5, 2/5 Apple cable is approximately these lengths before connectors are attached:
26 @ 22" / 560 mm (aligned with red stripe)
26 @ 18" / 460 mm
8 @ 6" / 150 mm
The original 2/10 Apple cable is approximately these lengths before connectors are attached:
6 @ (unused) (aligned with red stripe)
20 @ 18" / 460 mm
26 @ 25" / 635 mm
8 @ 6" / 150 mm
Connectors for Twiggies, Lite Adapter, Widget Data
26 pin IDC socket (correction: original Apple connectors do not have the polarizing bump, and do have the additional strain relief clip)
Clear labelling and the polarizing bump are my recommendation because:
a) the pin 1 stripe of the 60 conductor cable is NOT oriented to match pin 1 of the Upper Twiggy connector
b) the Lower Twiggy/Lite Adapter connector is reversed compared to the Widget Data connector
Connector for 3.5" drive (2/10 cabling only)
20 pin IDC socket (correction: original Apple connectors do not have the polarizing bump, and do have the additional strain relief clip)
Connector for Power Button / Keyboard Jack
10 pin IDC socket, without polarizing center bump
The male header on the assembly does not have a slot for the polarizing bump
If available choices include feed-through/open-end and closed-end, the open-end is often preferable as it can be easier to align, permits cable entry from either side, and is usable in more situations.
There are currently quite a few manufacturers of these with varying styles. Parts suggested below are a style that can sometimes be taken apart without breaking it. Although they are supposed to be single use, if it is crooked it won't work at all.
Currently in-stock (2024-06-01):
26 pin IDC socket: (2 required for 1/5, 2/5 harness)
DigiKey MKC26A-ND @ US $1.84
aka 3M 89126-0101
(this is selected to have a center polarizing bump as the cable stripe is not where one would expect, the non bump version is 89126-0001)
20 pin IDC socket:
DigiKey MSC20A-ND @ US $1.90
aka 3M 89120-0001
(correction: original Apple connectors do not have the polarizing bump, and do have the additional strain relief clip)
10 pin IDC socket:
DigiKey MSC10A-ND @ US $1.45
aka 3M 89110-0001
(Needs to NOT have a center bump as the keyboard jack/power button assembly connector does not have a slot for it)
Potential possibilities for replacing the card edge:
60 contact card edge wire-wrap:
Mouser 587-345-060-540-802 @ US $12.72
aka EDAC 345-060-540-802
60 pin IDC socket (2 may be required):
DigiKey MSC60A-ND @ US $2.91
aka 3M 89160-0001
edit: added correction that the Apple original connectors do not have the center polarizing bump, including them for the 26 and 20 pin sockets is my own suggestion