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CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Thu Jan 18, 2018 6:26 pm
by Paulo P
Here are the pictures of my Atari STe motherboard.

IMG_20180118_130655.jpg
IMG_20180118_130655.jpg (4.04 MiB) Viewed 10866 times
What is this cable for? Does anybody know?
What is this cable for? Does anybody know?
IMG_20180118_130749.jpg (4.06 MiB) Viewed 10866 times

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Thu Jan 25, 2018 11:07 am
by rubber_jonnie
I've seen that wire a couple of times now, I strongly suspect it is a factory 'bodge'.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Thu Jan 25, 2018 11:13 am
by exxos
rubber_jonnie wrote: Thu Jan 25, 2018 11:07 am I've seen that wire a couple of time now, I strongly suspect it is a factory 'bodge'.
I seen it as well. If someone looked up what pin it was on the IC, then see whats going on better. Think they just added a pull up to a pin as the wire goes to the SIL array.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Thu Jan 25, 2018 12:52 pm
by Maeke
I have the same wire on my ste.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Fri Jan 26, 2018 11:07 am
by rubber_jonnie
Unless I'm counting wrong, that wire is going to pin 1 of the Shifter.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Sun Feb 04, 2018 10:54 am
by Paulo P
I read somewhere few days ago, that this is for some voltage stability reason. I don't know if this is right or not.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Wed Apr 18, 2018 5:14 pm
by Paulo P
And here are the pictures after recap and some other little improvements (for example, LMC mixer audio fix). More here:

- https://www.exxosforum.co.uk/atari/last/ ... /index.htm ("STE LMC MIXER AUDIO FIX")
- http://forum.8bitchip.info/hardware-16/ ... er'-error/ ("Fixing STE microwire "mixer" error")

Motherboard_after_recap-01.jpg
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Motherboard_after_recap-02.jpg
Motherboard_after_recap-02.jpg (4.63 MiB) Viewed 10476 times

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Fri Apr 20, 2018 8:58 am
by Paulo P
I've noticed that one chip on the left of the processor is missing on my board compared to other STe mainboards. Does anybody know, what is it good for?

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Fri Apr 20, 2018 9:02 am
by exxos
Paulo P wrote: Fri Apr 20, 2018 8:58 am I've noticed that one chip on the left of the processor is missing on my board compared to other STe mainboards. Does anybody know, what is it good for?
Its the blitter... Its integrated in the large SMT chip to the left on later machines.

Re: CA4003290 Rev (C300779-001 Rev B 2) 1989 - Atari STe

Posted: Fri Apr 20, 2018 9:14 am
by Paulo P
exxos wrote: Fri Apr 20, 2018 9:02 am
Paulo P wrote: Fri Apr 20, 2018 8:58 am I've noticed that one chip on the left of the processor is missing on my board compared to other STe mainboards. Does anybody know, what is it good for?
Its the blitter... Its integrated in the large SMT chip to the left on later machines.
Thanks very much for your answer. I had a little bad feeling that my board has missing something. :)