FP6321A drop-in replacement
This is the board that was blown by the FSP F350-A, it's a Biostar 945GC-M4, finally get the time to give it a try at fixing it but with not so much hope, since this wasn't a badcaps issue I decided to post it here in case that someone find it useful.
The board didn't power on, fan does not spin at all however 3VSB was present, found 3 mosfet (Nikos P0903BDG) and a SOP-8 IC (FP6321A) shorted, one of the mosfets was in cpu vrm and the other two in a DC-DC converter along with the FP6321A which is a 300Khz fixed-frequency synchronous buck controller, all shorted mosfets were replaced but couldn't find any FP6321A in my junk box however I found in some russian forums that APW7120, RT9214 and a few others could be suitable replacements, datasheets seems to back that, anyway I scrapped both (APW7210 and RT9214) from dead boards and tried the APW7120 first but that was a no-joy, maybe I just killed the chip during the scrapping because I don't own any SMD rework tool so soldering/desoldering was made with my soldering iron and the burnt marks in the pictures can confirm that.
Next I replaced the APW7120 with the RT9214 and this time the board finally powered on, quick testing with a Prescott Celeron 2.26GHz and some DDR2 confirmed that the board was indeed alive and posting however my real surpise was the fact that this board DOES SUPPORT MOBILE P4's! I got 3 of them ranging from 2.8 to 3.2GHz like three years ago from old VAIO PCG-KxxF series laptops and none of the 478 boards that I have put my hands on ever posted with any of them, not even this one and then this cheapo board just works prefectly with any of them, although mosfets from CPU VRM gets somewhat hot at 78°C but that is thanks to the Mobile Pentium 4 538 that was used in the test.
Back to topic the board passed 12hrs of Memtest and AIDA stability test (FPU stress), full install of Win 7 SP1 + some software and around 4hrs of normal use, email, tube, mp3 play and office suite so I can confirm that RT9214 is a possible drop-in replacement for FP6321A.
The board didn't power on, fan does not spin at all however 3VSB was present, found 3 mosfet (Nikos P0903BDG) and a SOP-8 IC (FP6321A) shorted, one of the mosfets was in cpu vrm and the other two in a DC-DC converter along with the FP6321A which is a 300Khz fixed-frequency synchronous buck controller, all shorted mosfets were replaced but couldn't find any FP6321A in my junk box however I found in some russian forums that APW7120, RT9214 and a few others could be suitable replacements, datasheets seems to back that, anyway I scrapped both (APW7210 and RT9214) from dead boards and tried the APW7120 first but that was a no-joy, maybe I just killed the chip during the scrapping because I don't own any SMD rework tool so soldering/desoldering was made with my soldering iron and the burnt marks in the pictures can confirm that.
Next I replaced the APW7120 with the RT9214 and this time the board finally powered on, quick testing with a Prescott Celeron 2.26GHz and some DDR2 confirmed that the board was indeed alive and posting however my real surpise was the fact that this board DOES SUPPORT MOBILE P4's! I got 3 of them ranging from 2.8 to 3.2GHz like three years ago from old VAIO PCG-KxxF series laptops and none of the 478 boards that I have put my hands on ever posted with any of them, not even this one and then this cheapo board just works prefectly with any of them, although mosfets from CPU VRM gets somewhat hot at 78°C but that is thanks to the Mobile Pentium 4 538 that was used in the test.
Back to topic the board passed 12hrs of Memtest and AIDA stability test (FPU stress), full install of Win 7 SP1 + some software and around 4hrs of normal use, email, tube, mp3 play and office suite so I can confirm that RT9214 is a possible drop-in replacement for FP6321A.
Attached Files
, but it should be something non critical if the board works, what is supposed to feed that regulator's output?
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