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ASUS P2B-B Voltage regulator swap - Adding support for coppermine processors

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First post, by RockstarRunner

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I recently acquired a PC with an ASUS P2B-B Rev 1.01 running a P2 350.
The board revision is 1.01 which officially supports processors requiring a minimum of 1.8V, so basically no Coppermine CPUs.

ASUS made a Rev. 1.02 of this board that does support 100mhz fsb Coppermine processors, so I was interested in what were the differences, and would it be possible to somehow mod the older revision board in a similar manner.

After some digging around the net, I found this link, where it mentions you can potentially swap the voltage regulator chip, and along with the latest bios, you should be good to go:
https://web.archive.org/web/20150322010811/ht … pgrade_faq.html
I also found another post of someone actually trying this:
https://diarywind-com.translate.goog/blog/e/a … B&_x_tr_pto=nui

The Rev. 1.01 board has an Intersil HIP6019CB PWM controller, and the Rev. 1.02 has an Intersil HIP6019BCB PWM Controller.
I looked around on eBay and managed to find a Chinese seller that claimed to have the chip, it was cheap, so I took a chance and ordered it

The chip eventually turned up, and I took it to my friend who is good with electronics, and he said it's difficult to check the functions of the chip out-of-circuit, so he did couple of basic tests, then we just had to give it a shot and hope nothing smoked.

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Installation:

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Reply 1 of 13, by RockstarRunner

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First test done with no cpu, ram or anything else connected, no pops or smoke, so far so good.
Next we added the P2 back to the system, along with some ram, the machine posted as normal, and the bios reported a VCore of 2.0V (this is correct for the P2 350).
Then came the big test, swapping out the P2 for a P3 850 Coppermine SL43F https://www.cpu-world.com/sspec/SL/SL43F.html

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The machine posted, reported the CPU correctly, and the BIOS showed a VCore of 1.6V

I put the system through a series of tests in windows, and it performed perfectly. Result!

Reply 2 of 13, by Doornkaat

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Yeehaw!✊😉

Reply 3 of 13, by Datadrainer

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Great job @RockstarRunner. Thanks for sharing. 😀

Knowing things is great. Understanding things is better. Creating things is even better.

Reply 4 of 13, by teclillass

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Very good work, photos look great.
Enjoy that motherboard, now it's a cannon.

Regards

Reply 5 of 13, by RockstarRunner

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Update!
After doing the above mod allowed me to run Coppermine processors, I then started looking into Tualatin adapters.
I picked up a Slotket adapter off eBay, one which supports Coppermine CPU's (important, most just support the old Celerons)

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Then I purchased a 1.4Ghz Tualatin Celeron (100mhz fsb) with built-in coppermine adapter from a eBay seller in South Korea (well known to these forums I believe)

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The Tualeron runs with a 1.5V V-Core, which the new voltage regulator will happily supply.
The bios recognizes the CPU, but does issue a warning that the CPU is pulling only 1.5V, but this can be ignored, as I think it's just the BIOS not expecting such low voltage CPU.
Everything is working fine, and I'm happy this board is now even more flexible.

Reply 6 of 13, by rasz_pl

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>Then I purchased a 1.4Ghz Tualatin Celeron (100mhz fsb) with built-in coppermine adapter from a eBay seller in South Korea (well known to these forums I believe)

So I looked it up and Im confused. Original Tualatin mod required joining 2 pins together and isolating 3 pins from the board. Did you have to cut CPU pins/did it come with pins pre-cut?

https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
https://github.com/raszpl/440BX Reference Design adapted to Kicad
https://github.com/raszpl/Zenith_ZBIOS MFM-300 Monitor

Reply 7 of 13, by RockstarRunner

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Adapter (like a thin PCB that fits under the CPU) came pre fitted, so I didn't have to do anything than put the CPU in the slotket. I believe he cuts those pins when he installs the adapter.

Reply 8 of 13, by rolierop

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Will this mod also work on the Asus P2B-F board?

LuckyStar 486E C2 | Intel 486DX4 100 WB | PicoGus+WaveblasterPi
Gigabyte GA-5AX | AMD K6-2 500 | Sound Blaster Live! + PicoGus
Asus P2B-F|Intel Pentium III 733 | Yamaha Audician 32 + Dreamblaster
MSI P35 Platinum | Intel Xeon E5450 | Sound Blaster Audigy2

Reply 9 of 13, by RockstarRunner

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Check this, you may already have the newer chip, depends on revision. That said, if you have the older chip, you should be able to swap it, it's pin compatible, and some revisions do have the chip.

Re: Asus P2B-F Slot 1 Retro PC

Reply 10 of 13, by rolierop

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RockstarRunner wrote on 2024-05-03, 18:49:

Check this, you may already have the newer chip, depends on revision. That said, if you have the older chip, you should be able to swap it, it's pin compatible, and some revisions do have the chip.

Re: Asus P2B-F Slot 1 Retro PC

Thanks! I will let you know.

LuckyStar 486E C2 | Intel 486DX4 100 WB | PicoGus+WaveblasterPi
Gigabyte GA-5AX | AMD K6-2 500 | Sound Blaster Live! + PicoGus
Asus P2B-F|Intel Pentium III 733 | Yamaha Audician 32 + Dreamblaster
MSI P35 Platinum | Intel Xeon E5450 | Sound Blaster Audigy2

Reply 11 of 13, by rolierop

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rolierop wrote on 2024-05-04, 07:37:
RockstarRunner wrote on 2024-05-03, 18:49:

Check this, you may already have the newer chip, depends on revision. That said, if you have the older chip, you should be able to swap it, it's pin compatible, and some revisions do have the chip.

Re: Asus P2B-F Slot 1 Retro PC

Thanks! I will let you know.

I finally got to it. Sadly it has the HIP6019CB installed. For now I will keep it as is.
And (100Mhz) slot 1 Coppermine CPU's are hard to find anyway.

LuckyStar 486E C2 | Intel 486DX4 100 WB | PicoGus+WaveblasterPi
Gigabyte GA-5AX | AMD K6-2 500 | Sound Blaster Live! + PicoGus
Asus P2B-F|Intel Pentium III 733 | Yamaha Audician 32 + Dreamblaster
MSI P35 Platinum | Intel Xeon E5450 | Sound Blaster Audigy2

Reply 12 of 13, by Kane 93

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Can this mode version of the ASUS P2B-B Rev 1.01 run at 133MHz FSB or only at 100MHz What is the max FSB speed ?? Thanks in advance kane 😀

Reply 13 of 13, by PARKE

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Kane 93 wrote on 2025-03-13, 14:11:

Can this mode version of the ASUS P2B-B Rev 1.01 run at 133MHz FSB or only at 100MHz What is the max FSB speed ?? Thanks in advance kane 😀

According to the info here:
https://theretroweb.com/motherboards/s/asus-p2b-b#docs
it has a W83194R-39A clock chip plus 4 jumpers needed to select 16 fsb frequencies between 66 and 150MHz. so in theory 133 is an option.

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