# 9800PRO Possible Fan Control MOD



## Sharpshooter (Sep 5, 2004)

Hi,

    From what I`ve been able to investigate Fan Control only exists on 9800PRO Models if the 9800PRO has the "chip"(I suspect it is a bipolar transistor) which is marked in the Fan Control Article here in Tech PowerUp!. I`ve read the Datasheet for the LM63 temperature Control Chip and in that datasheet there is a typical application circuit which probably is the same that Ati`s Reference Cards use. In that Circuit the PWM output of the LM63 is connected to the Base of a MMBT2222A Bipolar Transistor. Knowing this I searched the Datasheet of this transistor and found out that it comes in the exact same package as the unfilled space of the 9800PRO`s without this Fan Control chip(SOT-23). The information I`ve not been able to gather is exactly what chip is in that space. Maybe someone with the chip is able to inform us what chip is it ? A photograph of the area would be great.

    My intentions with this is putting that chip in it`s place to get Fan Control on the Radeon 9800PRO`s with the LM63 IC. If the Fan Control chip turns out to be the MMBT2222A then all that needs to be done would be soldering that transistor in place. But, since the Fan is running at full speed always then the power must be connected to it always. By looking at the typical application circuit I would say that somewhere on the PCB we need to cut the ground from the FAN, supposing the transistor is connected correctly to the FAN. Otherwise we would have a shorted CE juntion on the transistor. I`m saying this because on my PCB I don`t see any pins shorted where the transistor takes place. Therefore the short to ground must be somewhere else.
     The other possible problem is that when you get everything done and turn on your computer I don`t know what would be the FAN doing, I suspect it has to be something with the LM63`s programming but I don`t know about that. Maybe w1zzard can help with this.

Thanks in advance.

PD: Sorry if this is in the wrong forum, but I expect a better response in this forum.


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## Sharpshooter (Sep 7, 2004)

Anyone can tell me what chip "controls" the voltage to the FAN ?


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## Sharpshooter (Sep 11, 2004)

Anyone ? Maybe this should be moved to the hardware forum, I´ll leave it to the Moderator Criterion.


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## Sharpshooter (Sep 15, 2004)

Any Suggestions ?


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## Guden Oden (Sep 15, 2004)

Is your 9800 board revision a "true" 9800 (R350), or a 9800 XT marked as a Pro (R360)?

Mine's a plain ol R350, and I would be interested in hacking in temp reading somehow but I dunno if there is a LM chip present at all, no matter if it's equipped with a bipolar transistor or not...


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## W1zzard (Sep 15, 2004)

lm63 is only present on xt pcb .. see the "does my ati card support temp monitoring" article here


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## Sharpshooter (Sep 16, 2004)

I don´t think you can "hack" temp reading if there is no temp monitoring chip at all, otherwise ATITool would detect it. What you can do is buy a temperature sensor. Anyway this question has nothing to do with this thread.


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## foreignkid (Sep 16, 2004)

THeres a guy over at hardforums that added an lm63 to his 9600xt and got thermal monitoring and all that workiing... but that was a while back, and I think you might have to do a little bit more stuff than he did...


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## Uber_Dude (Oct 4, 2004)

*Can I Help?*

I have a 256MB\256bit 9800PRO on an XT board. If you can post a pic with the area circled or something, I will pull my card and get the info you need.


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