Re: How much of a ][ is needed to twitch?

[probarge@bigfoot.com]

I have a scan of the apple II troubleshooting charts if you would like
them let me know its about 8.6 meg


On Sun, 11 Feb 2007 13:51:33 +1100, Tristan Mumford
<xtristan.xmumford@xgmail.xcom> wrote:

>This may seem like an odd question, but how many components can I pull out
>of an apple ][, well an identical clone anyway to see some signs of life?
>
>I'm in the mood to attack my infirm clone to try to get it running again.
>As it is I'm fairly certain the problem isn't the CPU or ROMS. About a month
>ago I was doing a random pull test. Essentially pull a chip, power up and
>see what changed. The most difference that pulling a chip made was making
>the screen all white. Other than that all that really changed was the
>pattern of 'garbage' on the screen. Although I'm sure the garbage pattern
>would probably tell a story to some people it doesn't to me.
>
>I'm hopeful of a solution that doesn't involve me blindly replacing chips
>until I find the culprit.
>
>This all reminds me, is there an Apple2 schematic available? It would help
>me to no end... and also help me with a conceptual future project. A
>reduced logic Apple2 clone. Nothing exciting. Just integrate the RAM and
>ROM chips to reduce chipcount, and a few other minor fiddles for my own
>contentment, like AT/X board layout and PS/2 keyboard support. It's not a
>short term project by any means, but I know it's by all means achievable.
>
>Anyway, back to it. The clone ][.
>I used a replacement power supply to eliminate that. I've pulled the ROMs,
>CPU, and chargen with no real effect. Pulling various RAMs affects the
>pattern a little like leaving alternating gaps in the garbage.
>Strangely enough the patches of random garbage slowly dissapear and turn to
>black. After a while no more patches stabilise though.
>
>I know I've posted about this in the past, but I still want to fix it and
>I'm after any input that can be given on a systematic method.
>
>Tristan.