bogdanpaulb wrote on 2022-12-21, 08:39:

Hi ,
many socket A motherboards with an isa slot (kt133) don't have a multi selector or fsb selector . Here is a pic with a hard modded Palomino 10.5 x 133 and how to get a 14x multi from it . Don't go to deep with the cuts , they are on the surface , do it gradually and use a multi/ohmmeter to check the conductivity of the traces . In the end you should get from a 10.5x , a 14x . It does not affect fsb , vcore or cpu cache . Do it at your own risk !

It would be nice if you explained in detail what exactly you did.

Btw I've always wondered if in such a way it could be possible to resurrect damaged/dead AXP CPUs with damaged cache by disabling half the cache.

I’d imagine all he’s done is a hardmod on the bridges (cutting some with an xacto, filling some of the pits with cyano and then painting the bridges with demister repair paint) and following a bridge calculator like this one:

https://www.ocinside.de/workshop_en/xp_painting/

Has anyone ever tried to make a pcb that bga solders to this and gives switches or something like that?

Sphere478 wrote on 2022-12-31, 20:10:

Has anyone ever tried to make a pcb that bga solders to this and gives switches or something like that?

I’m not sure it’d work. One thing would be making it thinner than the exposed cpu die so that the HSF still made decent contact. The next (and likely larger) hurdle would be keeping signal strength over the distances added to the length of the traces. Early Socket A CPUs were easily unlocked using a decent leaded pencil, but palomino and newer all required the use of conductive paint (or better) due to the old method not working any more, likely due to impedance.

You also have the other problem of the need to open all the bridges on the CPU before applying the PCB.

You might get away with something like the films used to mod S771 to S775, as they are both thin enough and directly connected without much additional trace length. But again you’d need to open all the bridges on the CPU first and then have a different film for each possible combination of settings.

EDIT: You’d also need a different PCB or film layout for Thunderbird, Palomino, Thoroughbred/Barton.

If all you're doing is modifying the multiplier, it's better to just modify the socket (on the underside of the MB, not the actual socket)...

Bridge modding is worthwhile for several things, notable:

Athlon to Athlon MP mod
Athlon to Athlon Mobile Mod (grants access to software multiplier changing in DOS)
Unlock multiplier on multiplier locked CPUs

I've done both mods, with the paint and with the socket. The painting takes some attention to detail -- and better make sure you actually get conductive paint if you're buying it from China. Test it with a multimeter first.

paradigital wrote on 2022-12-31, 20:24:

I’m not sure it’d work. One thing would be making it thinner than the exposed cpu die so that the HSF still made decent contact […]
Show full quote

Sphere478 wrote on 2022-12-31, 20:10:

Has anyone ever tried to make a pcb that bga solders to this and gives switches or something like that?

I’m not sure it’d work. One thing would be making it thinner than the exposed cpu die so that the HSF still made decent contact. The next (and likely larger) hurdle would be keeping signal strength over the distances added to the length of the traces. Early Socket A CPUs were easily unlocked using a decent leaded pencil, but palomino and newer all required the use of conductive paint (or better) due to the old method not working any more, likely due to impedance.

You also have the other problem of the need to open all the bridges on the CPU before applying the PCB.

You might get away with something like the films used to mod S771 to S775, as they are both thin enough and directly connected without much additional trace length. But again you’d need to open all the bridges on the CPU first and then have a different film for each possible combination of settings.

EDIT: You’d also need a different PCB or film layout for Thunderbird, Palomino, Thoroughbred/Barton.

How tall is the die? A film pcb might do it.

Yeah. Gotta open the bridges.

If anything like other cpus distance shouldn’t be a big deal. Copper and solder. To a resistor and switch.

But yeah, prob no need 🤣. Paint mod and done.

Tetrium wrote on 2022-12-31, 18:47:

bogdanpaulb wrote on 2022-12-21, 08:39:

Hi ,
many socket A motherboards with an isa slot (kt133) don't have a multi selector or fsb selector . Here is a pic with a hard modded Palomino 10.5 x 133 and how to get a 14x multi from it . Don't go to deep with the cuts , they are on the surface , do it gradually and use a multi/ohmmeter to check the conductivity of the traces . In the end you should get from a 10.5x , a 14x . It does not affect fsb , vcore or cpu cache . Do it at your own risk !

It would be nice if you explained in detail what exactly you did.

Btw I've always wondered if in such a way it could be possible to resurrect damaged/dead AXP CPUs with damaged cache by disabling half the cache.

I started with a Palomino 1600+ ( 10.5 multi so 1050 ) . I used a Palomino 2100+ and some models in between pictures to get an idea of how the L lines are organised , then i used a Athlon SFF 1600+ picture so i can roughly extrapolate which are used for multi ( L3 , L4 and L10 ) , fsb and core . For the mod i used : a multimeter , a soldering station ( flux and solder ) , a cutting tool and thin wire from a phone speaker . If you have the Thunderbird core which is ceramic you can use electrically conductive paint or something similar , so you can scrap the soldering station and the thin wire from the list . However if you have Palomino or newer , they are on multi layer textolite . If you use a microscope to look at the original factory cuts , you can already see the second layer with traces so using a conductive liquid/paste it's a no go , or you can do it , but risk abnormal behavior/damage . The traces that you have to cut/connect are on the top layer and lead to the points encircled ( i used a L1 image because it was handy , but it's the same thing ) . You can use them to solder a wire if you need to connect or measure for continuity if you need to cut ( again , if you need to cut , take your time , do it slowly . It's very easy to get to the second layer and risk damage ). In the last pictures you have the cpu running at 1400 ( 14x100 ) and 1569 ( 14x112 which is the max for my motherboard ) .

I recommend Athlon XP Mobile with Barton core, it's cool and fast. You change multiplier on-the-fly from DOS or Windows.

Got one in my all-arounder built on Abit KT7A.

dj_pirtu wrote on 2023-01-13, 07:27:

I recommend Athlon XP Mobile with Barton core, it's cool and fast. You change multiplier on-the-fly from DOS or Windows.

Got one in my all-arounder built on Abit KT7A.

Did you manage to change multipliers on the fly on your KT7A? I thought KT133A didn't support that yet?🤯

Yes it works, it needs a little trick...

Re: Abit KT7A (KT133A/VIA686B), Athlon XP Mobile 2500+

My KT7A takes 150FSB so from 2x (300MHz) up to over 2GHz. It really don't help to clock much over 2GHz because SDRAM memory bandwith really limits here.

AND, there's VIAFSB so you can set FSB on-the-fly too.

dj_pirtu wrote on 2023-01-13, 09:45:

Yes it works, it needs a little trick... […]
Show full quote

Yes it works, it needs a little trick...

Re: Abit KT7A (KT133A/VIA686B), Athlon XP Mobile 2500+

My KT7A takes 150FSB so from 2x (300MHz) up to over 2GHz. It really don't help to clock much over 2GHz because SDRAM memory bandwith really limits here.

AND, there's VIAFSB so you can set FSB on-the-fly too.

Wow, thanks, I totally missed that!