Lisa I/O Port Test Card

[sigma7]

This topic is to document the Lisa I/O Port Test Card, labeled on the silk screen as 890-4010-

There are other test cards, eg. the DMA Test Card eg. 890-4016-A, which have a separate topic.

[sigma7]

Attached are:

• Reverse engineered schematic from board labelled 890-4010-A, with white silkscreen and 337 handwritten in the rectangle beside the Apple logo
  
• ROM image from that board
  
• MacNosy disassembly of the ROM image
  

It appears that the card was primarily an interface to an Apple ][ or /// that would provide the Lisa test code to be run.


Connectors:

• 10 pin header (J1), which has pins routed to the ADC; presumably for a cable to clips to measure voltages at various places in the lisa.
  
• female DB-25 (J2), used to connect to the parallel port of the Apple ][ or ///.
  
• female DE-9 (J3), possibly to attach to the Lisa Under Test's mouse port to simulate mouse signals to test the COPS etc.
  
• 3 pin header (J4)
  

In addition to the 4 analog inputs routed from J1, the 8-input ADC is also configured to measure +5, +5STBY, the PB0 output of one of the 6522s, and the voltage across a 1n4150 diode.

[sigma7]

The I/O Port Test card seems to have multiple variants.

Many of the boards seen on eBay have had the +5V load resistors (RL1-RL7) removed or not installed.

Attached are pictures of another version of the I/O Port Test card, also 890-4010- but with no revision letter. It has a yellow silkscreen whereas the reverse engineered board (Rev -A) had a white silkscreen. The components are very similar (if not identical), however the layout has some changes.

The modifications on the bottom of the board connect R16 and R21 to the 5V Reference voltage (as in the schematic of the rev -A board), instead of the 5V power bus.

[compu_85]

10 pin header (J1), which has pins routed to the ADC; presumably for a cable to clips to measure voltages at various places in the Lisa . . .  In addition to the 4 analog inputs routed from J1, the 8-input ADC is also configured to measure +5, +5STBY, the PB0 output of one of the 6522s, and the voltage across a 1n4150 diode.

One of my cards has the small harness with clippin leads. I can take photos later on if it would be helpful. I did not get any notes about where they hook up.

-J

[sigma7]

One of my cards has the small harness with clippin leads. I can take photos later on if it would be helpful.

Yes, additional photos please!

If your board is any different, a description of the differences or photos would also be good to have.

[compu_85]

Attached is a photo of my 2 I/O port test cards. One is marked with SN 119, "B" on the ROM, and has the resistors installed.
The 2nd card was missing its ROM when I got it, and also has the resistors clipped off.
Both are part 890-4919-A. Both have a 303 Test OK sticker. The PCBs are nearly identical, the one marked SN 119 has evidence of screws being installed on the ports at some point but were removed. Both are marked RLM-1 in the copper on the back, SN 119 is also marked with an SCC logo.
The date codes on most of the chips for both are the same! (excluding the 6552s).

The cables came with SN 119. The 25 pin cable is marked "To parallel port connector" and "to J2 on I/O port test card". The 9 pin cable is not marked, though one side has the special socket to clear the tabs on the Lisa 1 style mouse connector.

The clippin lead harness has the black probe connected to pin 1, red to pin 3, yellow to pin 5 and blue to pin 7.

The date codes on the yellow silkscreen board pictured above look earlier.

Additionally, a "Serial Port Test Card" is pictured. Simple board with some loopback connections.

Thanks,

-J

[compu_85]

This card gives an entry in the startup from menu.

When selected, a message very briefly pops up saying Awaiting Apple Input, then card error 98, and the system crashes and restarts.

[sigma7]

It was probably obvious to some of you, but I've just realized that the mystery header on the 2/10 I/O Board is almost certainly for use with this Lisa Test card. The mystery header has no ground pin, so whatever connects to it needs (probably) to have a ground common to the same computer; an expansion slot card fits this requirement.

If a 10 pin to 10 pin socket header cable is used to connect J1 on the Lisa Test card to J1 on the 2/10 I/O Board, then we have the following 3 connections:

Code Select Expand


Pin  I/O  Test Card  ...connected to
     J1     J1
1   CONT  J1a/J1j  ...R15
3   SPKR  J1c/J1h  ...R19
5   +5B2  J1e/J1f  ...R7


(The double connections on J1 of the test card are so the connector can be plugged in backwards and make the same connections. ie. pins 1 & 10 are at opposite corners so will make the same connection when the connector is rotated 180 degrees. This might reduce fiddling when setting up for testing.)

Presumably the cable with clips is for testing I/O Boards that don't have the J1 header, in which case to make the same connections, the clips would be attached:

Code Select Expand


Test Card         I/O Board
J1     Clip
1,10   Black      CONT  U10A-7
3,8    Red        SPKR  U10A-13
5,6    Yellow     +5B2  U7F-14

(There are easier/better connection points for these signals at resistor leads, but since a resistor has 2 ends, pin numbers are less ambiguous.)


One mystery clip remains...

The Blue one connected to pins 7,4 of J1: J1g/J1d  ...R9

On the test card this is divided by 2 before measurement, which is the same as the +5B2 measurement input, so may be used similarly. Since the signal is not on the J1 header of the 2/10 I/O Board, one can presume it is for a signal that isn't on the 2/10 Board. As the battery circuits exist on the 1/5 I/O Board, but not the 2/10, perhaps the clip was connected to +5B or another voltage related to the battery.

Or, if there is a test card cable that has a 10 pin socket header at both ends, along with one blue clip on a flying lead, perhaps it went to another board.

[compu_85]

Great detail. I always wondered what that socket was for.