Can you identify this STE motherboard modification?

[Harrison]

I purchased an STE from ebay last year and opened it up today to upgrade the TOS roms. When I removed the floppy drive I noticed 2 wires connected to 2 of the motherboard chip's legs and running off under the main motherboard shielding. So I lifted the main shielding under the keyboard to investigate further, and these 2 wires run to a chip which has been soldered to and is piggy backing an existing chip on the motherboard.

I've no idea what this mod is for so hope someone here can help. I've taken a couple of pictures of this and hope they will help someone identify and explain to me what this mod was originally done for? Does it have a purpose, or is it some kind of repair?

[simbo]

this is a factory mod

look here at one of my first few posts many years ago

http://www.atari-forum.com/viewtopic.php?f=15&t=3506

dont worry about it
its an atari bobo that made sound fail on boot
but work in games or something no fm from o/s cant remember
but i read about on an old bbs after i found it in an ste someone donated to me

sufice to say its doing a needed job

[Harrison]

Thanks for the quick reply. I've very surprised its a factory mod as it doesn't look the most professional of soldering jobs. Are all STEs like this? Or was this issue fixed with later models?

[insanity]

Hi,

Since you've opened the ST, could you take a photo of the whole motherboard for
our wiki?

See here:
http://www.atari-forum.com/wiki/index.p ... _revisions

Thanks

baz

[Harrison]

@ Baz. I've not removed the whole metal shielding. I just opened up the front half and lifted it to look at the mod I had discovered, and to take the picture. But if I do ever remove the whole shielding then I will definitely take a pic for the Wiki.

[simbo]

ive noticed this mod only in early ste
later ste had the chip as standard fitted to its pcb

you have a rev 000 pcb
and its the ste with seperate blitter from glu
later ste had a glu/blitter combo
iir
in the schematic is a 74LS184 ?? and is u600 on the 1040ste02.tif page

[Stefan jL]

My STE does also have that fix.
I have done a photo of the PCB here: http://www.ym2149.com/atariste_pcb.jpg
There is also a wire on the LMC1992?

[farvardin]

It seems all the pictures for the motherboard revisions are missing on the atari wiki, it's a pity: http://www.atari-wiki.com/index.php/Ata ... _revisions

[catmando]

It seems all the pictures for the motherboard revisions are missing on the atari wiki, it's a pity: http://www.atari-wiki.com/index.php/Ata ... _revisions

I don't think the pictures are physically missing (they're still on disk), but the way the wiki links to them is broken at the moment, Dal still needs to resolve this issue.

[exxos]

I plan to start uploading my own motherboards to my site soon. I sent in a few to the wiki anyway, so should be a fair few going up. I only have STFM, STE boards here though. Maybe not all revisions, but I am sure some people will fill in the blanks over time

[Dal]

Pictures in the wiki are now working again. Had to roll back to an older version of MediaWiki which sucks, but I'll work on it in the dev environment and see if I can get the images working with the latest MW release when I get time.