Apple IIe PAL - Does not boot

8 posts / 0 new
Last post
Offline
Last seen: 1 month 1 week ago
Joined: Jan 19 2020 - 18:23
Posts: 5
Apple IIe PAL - Does not boot

Hello!

 

I have an Apple IIe model A2S2064. This has mainboard 820-0073-B, B607-0264-F.

 

This is the PAL version of the Apple IIe, and it's a UK model.

 

I removed the machine from storage, and on initial poweron, the PSU was ticking. I reseated the 80col expansion card, and the machine booted OK.

 

However, when I powered on the machine yesterday, the machine went immediately into the self diagnostics, and reported "KERNEL OK". Rebooting the machine with CTRL-APPLE-RESET starts the diagnostic again. 

 

The diagnostic looks normal compared to this video: https://www.youtube.com/watch?v=aOP7jwYNk6I

 

Except "KERNEL OK" is not displayed any more - the self test restarts immediately after the @ symbol screen.

 

I have tried to press CTRL-B to get the machine to boot into basic, but to no avail. The machine keeps looping the internal diagnostic over and over. If I press CTRL-APPLE-RESET the machine does reboot, so I know that the keyboard is connecting and working.

 

I have removed the Apple 80 Column card, and the problem persists.

 

Can anyone point me as to where I should start the diagnotics process?

 

Thankyou in advance!

 

Update: I reseated the keyboard cable connector, and now the machine reports "KERNEL OK" but I am unable to proceed any further. CTRL-APPLE-RESET restarts the diagnostic, to show "KERNEL OK"

 

 

Online
Last seen: 35 min 26 sec ago
Joined: Jun 18 2010 - 13:54
Posts: 218
Sounds like an issue with the

Sounds like an issue with the keyboard or cable/connector. Specifically the open and closed apple keys. Computer is acting as if they are both pressed or disconnected. Also make sure nothing is connected to the joystick and game I/O ports.

Offline
Last seen: 1 month 1 week ago
Joined: Jan 19 2020 - 18:23
Posts: 5
Nothing is connected to the

Nothing is connected to the joystick or game ports.

 

Is it possible to remove the keyboard completely to rule the issue out?

 

I know the machine will not fully boot without the connector, but can a 'dummy' connector be made, or pins be shorted on the ribbon cable so that the machine sees the keyboard connected?

Online
Last seen: 1 hour 18 min ago
Joined: Jul 5 2018 - 09:44
Posts: 479
nrg13 wrote:

Nothing is connected to the joystick or game ports.

 

Is it possible to remove the keyboard completely to rule the issue out?

 

I know the machine will not fully boot without the connector, but can a 'dummy' connector be made, or pins be shorted on the ribbon cable so that the machine sees the keyboard connected?

 

Removing the keyboard will make it fail the test.  You need to make the dummy connector or short pins as you say.

 

 

 

Offline
Last seen: 1 month 1 week ago
Joined: Jan 19 2020 - 18:23
Posts: 5
From page 313 of

From page 313 of "Understanding the Apple IIe"

 

 

This would seem to indicate that the machine thinks the keys are depressed if the keyboard connector is removed.

 

I can see that these are tied low by 470 ohm resistors on the keyboard schematic - i.e:

 

 

So am I right in saying that tying pins 7,5 of the keyboard connector should be pulled to ground through resistors to simulate an attached keyboard, with no keypresses? Or are there some other keys also?

Online
Last seen: 35 min 26 sec ago
Joined: Jun 18 2010 - 13:54
Posts: 218
nrg13 wrote:

So am I right in saying that tying pins 7,5 of the keyboard connector should be pulled to ground through resistors to simulate an attached keyboard, with no keypresses?

 

Yes that is correct. Although as long as the keyboard is not connected, you could just short both pins to ground (without resistors) at the keyboard socket on the motherboard. This should allow the computer to boot normally.

Offline
Last seen: 1 month 1 week ago
Joined: Jan 19 2020 - 18:23
Posts: 5
jeffmazur wrote:

[Yes that is correct. Although as long as the keyboard is not connected, you could just short both pins to ground (without resistors) at the keyboard socket on the motherboard. This should allow the computer to boot normally.

 

Thankyou Jeff - I will try this tomorrow and report back.

Offline
Last seen: 1 month 1 week ago
Joined: Jan 19 2020 - 18:23
Posts: 5
Good news!

Good news!

 

I found the correct keyboard pinout online here: https://gist.github.com/papodaca/5d854b296a5f7943e245

 

 

I was able to fabricate a small keyboard header from DuPont cables, that shorted pins 5,7 and 13. From the keyboard connector pinout, 13 is ground.

 

 

This allowed the machine to boot OK to the Apple IIe screen.

 

 

Next steps - fixing the keyboard :)

Log in or register to post comments