VOGONS


Reply 20 of 25, by a_h_adl

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Kahenraz wrote on 2021-09-23, 16:12:

The MOSFETs are pretty cool when paired with a 500Mhz Celeron but extremely hot with a 1.4Ghz Pentium 3. I installed little copper heatsinks on them to help. I wonder if they will be pushed even harder with the lower voltage.

The chip I ordered was through Aliexpress and is estimated to arrive sometime next month. I'll update this thread when I swap out the chip for testing.

It would be nice to see if chip swapping has worked or not.

Reply 23 of 25, by rasz_pl

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Kahenraz wrote on 2022-07-28, 07:28:

Unfortunately, my P2B died suddenly while in storage before I could try this modification.

My ASUS P2B motherboard died suddenly

short on the diode means mosfet is shorted, I wouldnt give up on P2B

Reply 24 of 25, by Kahenraz

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a_h_adl wrote on 2022-07-28, 10:30:

That’s sad. Have you checked the main regulator? I had two other mainboatds (not P2B’s tho) but chacking the main feeding circuit fixed them.

Which component is that?

Reply 25 of 25, by rasz_pl

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you can directly compare P2B 1.10 and 1.12 from manufacturing files (Fabmaster Test Expert) https://www.xwfix.com/?s=asus+p2b you will need https://openboardview.org/ to view the files. *.BOM includes detailed list of all components, sadly 1.10 revision is missing contents of this file.
Main difference seems to be addition of Chassis Fan header relocated Chassis Fan header to make room for second VPANEL header and VCore jumper - from what I remember this bumped Vcore by 0.1V or something like that. Sadly cant find manual for 1.12.
Interestingly P2B already had VID0-4 configuration jumper block ready! but its unpopulated and disabled by soldered R30A and RN99 (0 ohm jumper links). Removing those two will enable VID jumper block. I clearly remember using masking tape on three VID pins to manually change voltage on my Celeron 300A to 2.2V on P2B. Missing forest for the trees, 24 years later I finally see the VID pins waiting for me to mod them back on the motherboard 😀

1 why would Asus made an effort of implementing full Vcore override jumper block, and then disabling it with 0 ohm resistors?
2 I also realized VID0-4 pins go to HWmon chip WINBOND W83781D https://www.kernel.org/doc/html/v5.9/hwmon/w83781d.html https://pdf1.alldatasheet.com/datasheet-pdf/v … ND/W83781D.html The only thing this chip does with VID signals is report them back, they are wired to dedicated Inputs instead of universal I/O. What a Huge missed opportunity for implementing soft voltage control Bios menu! 🙁 (Btw Asus boardview files have this chip U6 pinout reversed by 180 degrees, oopise).