VOGONS


First post, by Prez

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Hi everyone !
Hope you're going fine.
I'm pretty new here, and old Msdos user trying to settle new machines based on cheap thin clients like the Fujitsu Futro s220 that you can find on Ebay for $30 for example. I wanted to share my discovery here, because i didn't find any infos like there :
After two days trying to understand why i got no sound with a Yamaha YMF724 and a SoundBlaster PCI 128 on this machine, i finally understood why when i tried to bypass the amps on the cards to "listen" directly to the chips themselves, and it worked ! That meant the amps were not working. While searching a reason why, i find that these cards have in common to use -12V and +12V lines on the PCI bus for amplification. And guess what ? This Fujitsu Futro S220 just use a +5V power, no -12 nor +12, so it cannot feed the PCI bus with these voltages. End of story !!

Luckily, very cheap PCI soundcards on Ebay doesn't use these -12V, +12V lines. As for for example :
https://www.ebay.fr/itm/1X-4-Channel-C-Media- … JoAAOSwqspc1Nf5

Using the C-Media 9738 should ensure some DOS compatibility.

How do you check if your PCI card uses or not -12V, +12V ? Follow this guide :
http://www.arstech.com/install/cms-display/st … cipwrneeds.html

What is very annoying now about this story is that : How do you check easily when trying to buy a cheap thin client if it can provide those tensions or not ? 😒

Best regards
Philippe

Last edited by Prez on 2020-04-10, 14:56. Edited 1 time in total.

Old computers and videogames freak
President of french association https://mo5.com
Get better, get old ! 😁

Reply 1 of 4, by xjas

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Interesting, thanks for posting your result! I was under the impression it was PCI bus noise caused by missing filter caps on the riser board. Guess it could be a combination of both.

Looks like all my sound cards use the +12V line (pin A2.) TBH I didn't think -12V was even a thing on PCI.

Pretty cheeky of them to run the PCI out of spec like that. I wonder if it'd be possible to tap 12V in from somewhere else, or even an external PSU? The S220/300 takes mains voltage (100~220V) so it MIGHT have 12V available somewhere in the rectification stage.

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Reply 2 of 4, by Prez

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Hi !
The power stage inside the SR220 is just about 5V, nothing else. You can try to use some small electronics cards that uses 5V and makes +12V, -12V, but it is a bit complicated just for using a card 😉
This type for example, a "step up" card :
https://www.ebay.fr/itm/5A-DC-DC-step-up-powe … 4V/153394984428

But i'm not sure about the noise generated by this solution ! Remember its just used by the amp.

ps: I found another topic on Vogons about the SR220 and a guy who didn't achieve using a pci soundcard, guess what, i'm sure its related.

best regards
Philippe

Old computers and videogames freak
President of french association https://mo5.com
Get better, get old ! 😁

Reply 3 of 4, by Prez

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Okay i did find a very small and ugly operation to have sound on these machines. Will do a new post for that very fast.

Old computers and videogames freak
President of french association https://mo5.com
Get better, get old ! 😁

Reply 4 of 4, by Prez

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Hi all !
Here the link to a new article on a bypass methode, quick&dirty 😉

Quick/easy/dirty mod to make thin clients like Fujitsu Futro S220 or TECO TR3540 works with some soundcards !

Old computers and videogames freak
President of french association https://mo5.com
Get better, get old ! 😁