wiretap wrote on 2020-11-12, 04:48:
I haven't looked into other versions. It should be easy to adapt (or work regardless) depending on the pinout of the IC.
Depending on the revision, your board should have either an ICS9148-26 or an ICS9150-08 clockgen. The former does not provide a 133mhz selection option. The latter does, but it is non-functional.
You will need to replace the clockgen with an ICS9250CF-08
Be aware that what you might find for sale online is the ICS9250BF-08. It's a fake. There is no such model. The "-08" suffix is important, and different iterations are not suitable.
Replacing the voltage chips is optional. Your board will probably have a HIP6004ACB. Tualatins will work with it, but they will be running at beyond the voltage specification. Ideally you want to replace them with HIP6004BCB.
EDIT (12/29/2020): Apparently the ICS9250BF does exist and they did come stock with some P2B-F boards. All I know is the one I got does not work properly so it's probably some other variant of the chip that is compatible enough to let the system POST but not to function completely properly.
Odd that ICS does not list the 9250BF in their product discontinuation sheets.
It's also worth noting that ICS used different logos for different years/batches, so it's very difficult to tell a genuine chip from a knock-off.
EDIT 2 (1/05/2021): Not only does the ICS9250BF exist, but the one I purchased and soldered into my board is actually working perfectly... What was in fact preventing my board from working properly was the fake or re-marked HIP6004CB... I replaced the original HIP6004ACB because I wanted to use <1.8V with Tualatin CPUs. I removed the Chinese part and replaced it with a HIP6004BCB from a dead board (Biostar VIA board with what I suspect is a dead northbridge) and the board works perfectly stable at 133Mhz.
So the mod was successful. Installed on the board is a PIII-S 1.4Ghz part. It's worth noting that the P2B-S used here was picky about slotkets. I tried several of them and the only one that works so far is the Abit Slotket III. But this is the case with the lin-lin adapter being used in conjunction with a slotket. We'll see if the Korean solder-on adapter gets the same result. Graphics card that I tested with was the GeForce 4 MX440, and it worked perfectly at an 89Mhz AGP clock. Stability was verified by looping 3DMark 2001SE and 99 for many hours.
In retrospect, the P2B at a revision >1.10 is probably a better choice for someone looking for a good Asus board but not wanting to desolder ICs (especially the 9150 which has a fine lead pitch). The P2B has three ISA slots instead of two, so you would be able to use say two sound cards plus some other ISA card of your choice, whereas the P2B-S only has two.
I will be re-capping the VRM of the board to conclude the refurbishment. The VRM consists of 6.3V 1000uF 8x11.5 Rubycon YXG as well as two or three 6.3V 1000uF 8x20 Sanyo WG. The former will be replaced with Nichicon HE and the latter with Nichicon HM.