shevalier wrote on 2025-12-06, 06:00:There is a 2.5V power input for Pentium 2, which is not used on Pentium 3 Coppermine/Tualatin (1.5V= Vtt).
It's just a jumper or […]
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myne wrote on 2025-12-06, 01:46:
H3nrik V! wrote on 2025-12-05, 09:01:
Don't some of them have voltage clamps on agtl voltages?
Some signals definitely changed from 2or 3v to 1.5 iirc and they definitely have to be reduced, but the main bus is fine at 1.5.
There is a 2.5V power input for Pentium 2, which is not used on Pentium 3 Coppermine/Tualatin (1.5V= Vtt).
It's just a jumper or processor PCB routing.
There is no need to shift anything in terms of level or limit anything.
Otherwise, there would be no first revision Celeron Coppermine 533A, which ran on unmodified Mendocino-only boards.
liverygone wrote on 2025-12-04, 17:14:
an ABIT BE6 (non-II) motherboard
As far as I remember, some early revisions of these motherboards, despite supporting voltages starting at 1.25V, have problems starting up.
Most likely, there are nuances with the CPU VID`s overdrive circuits.
There are two logic chips near the monitoring IC that do this.
If you figure them out, then most likely the entire modification of the board for starting Tualatin will boil down to cutting the wire, soldering the wire,
hello! thank you everyone for offering the help! and apologies i haven't replied, i have been researching and have found many 'o things! It seems like the best direction for this project is to go with a reverse‑engineered custom pcb. Thanks again to paradigital, myne, and everyone else who jumped in, I’ve mostly been theorizing so far and trying to understand how all the pieces fit together, but things are finally starting to make sense.
I ended up buying an ABIT BE6 off eBay https://share.google/UQWXh5zbXHw8CBvko, and since the board is already going to need some attention ie. recapping, checking the VRMs, and replacing a few tired MOSFETs, I figured this would be a good chance to build a proper custom setup around it. My idea at the moment is a simple, clean slotket style pcb that handles the basic pin rerouting for Tualatin compatibility, keeps the voltage lines safe, and avoids having to modify the CPU itself.
I’m also planning a custom bracket so I can mount a modern cooling solution. I really want to run a big AIO on this build (specifically the Arctic Liquid Freezer III Pro 420mm) since I’d like to experiment with higher overclocks once everything is dialed in (maybe even take a shot at some records). For now, though, I’m aiming at much safer clocks like ~1.7 GHz while I learn. I’m also on the hunt for 2×512 MB PC133 OCZ RAM that should handle the higher FSB speeds.
The author of the topic will tell us about this when he finishes reading the datasheet to the right place. :-)
The 5th harmonic […]
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The author of the topic will tell us about this when he finishes reading the datasheet to the right place. 😀
The 5th harmonic of 133 (150 for OC) MHz is already half a gigahertz, which is impressive.
Here, impedance matching and line length matching are already needed.
So he will still have to read the datasheets.
I'm not Shure what datasheet you are referencing would you kindly clarify?
Still very much learning as I go, and I’m sure I’ll need to refine the plan as I dig deeper, but that’s where I’m currently at. Any feedback or corrections are definitely welcome!
