Question on Mimeo 1 Boot Problem

5 replies [Last post]
Offline
Joined: Jan 23 2016
Posts: 8

Hi All,

I'm hoping someone can give me some pointers on some Mimeo 1 troubleshooting. I got my 2504 chips in the mail and got my video section working correctly. I have got the computer section populated now, and am having some trouble.

I've connected a PS2 keyboard with Mike's PS2->Apple1 adapter board. When I turn on the power, the keyboard adapter clears and resets the apple and I get a blinking @ cursor, but I do not get the / character on the line before.

I'm not sure of the boot sequence, or where to start diagnosis. I'm hoping the behavior I'm seeing gives some clues. Here's some pictures of my apple 1, keyboard, and the video I'm seeing on the monitor. I also uploaded a youtube video of what I'm seeing. https://youtu.be/RhLQCGEQLfw

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IMG_9748.jpg2.57 MB
IMG_9749.jpg1.18 MB
IMG_9750.jpg1.91 MB
IMG_9751.jpg1.62 MB

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Offline
Joined: Aug 16 2015
Posts: 56
Re: Question on Mimeo 1 Boot Problem

Actually, that looks like clear screen is working but reset is not. Have you tried it without the keyboard adapter by following the instructions at section 5.3 of the Mimeo Assembly Guide:

Quote:

Briefly short pin 12 (clear screen) of the keyboard socket to +5v [pin 16 of keyboard connector] and the screen should become clear. At this
point you should be able to reset the processor section and see a prompt be displayed. To reset the system and
get a prompt, use a temporary jumper to short pin 1 of the keyboard connector to a nearby ground pin (pin 9 of
keyboard connector).

If you get the backslash prompt with that procedure it suggests that the problem is with the keyboard adapter.

Offline
Joined: Oct 9 2011
Posts: 1063
Re: Question on Mimeo 1 Boot Problem

It's not clear from your video, but did you try the reset from the PS2 adapter as per Mike's manual? Or are you expecting it to happen automatically?

Offline
Joined: Jan 23 2016
Posts: 8
Re: Question on Mimeo 1 Boot Problem

Hi, thanks for the reply.

I have tried the manual clear and reset using a jumper wire, but I believe I had the same behavior. I'll go back and try it again to be sure. I'll shoot a video of what happens.

Pete

Offline
Joined: Jan 23 2016
Posts: 8
Re: Question on Mimeo 1 Boot Problem

Hi, thanks for the reply.

I believe I thought that with the S1 jumper set I would get the clear and reset automatically. I'll go back and double check. I'll try the manual clear and reset as well just to double check.

Pete

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Joined: Jan 23 2016
Posts: 8
Re: Question on Mimeo 1 Boot Problem

ok, I went back and tried the manual clear, and then reset using a jumper, and you are correct - the clear worked and got me to the blinking @. But when I shorted Pin 1 and Pin 9, nothing happened.

I'm not sure where to start.