Although not sure how practical it may be, I'd suggest wiring the fan headers for 7v instead of 5 or 12, if possible.

PcBytes wrote on 2022-06-08, 18:42:

Although not sure how practical it may be, I'd suggest wiring the fan headers for 7v instead of 5 or 12, if possible.

Totally impractical since the cpu socket has nothing higher than 5v.
It would require adding a boost converter to the interposer.
You might as well ask for it to be variable using some software tweaks.

Indeed, unfortunately without a buck converter, the fan will be 5 or 3.3v no buck converter is planned currently

The fan header will be totally optional. The user doesn’t need to use it.

There is more than enough power there to run the fan. I don’t believe line noise will be a problem but we will find out in prototyping 5v is more than enough to run a 12v fan at low speed. 3.3v is questionable but again, the header is optional

If you can make this adapter, you can make a 5v fan fit the header.

Great idea for a project. The only thing with the fan header is alot of fans tend to have a starting voltage of around 6 volts. It's possible that there will be fans that run at 5 volts no problem but I've had alot of fans refuse to start below 6 volts.

chrismeyer6 wrote on 2022-06-08, 20:48:

Great idea for a project. The only thing with the fan header is alot of fans tend to have a starting voltage of around 6 volts. It's possible that there will be fans that run at 5 volts no problem but I've had alot of fans refuse to start below 6 volts.

just use a 5v fan 😁

weedeewee wrote on 2022-06-08, 21:17:

chrismeyer6 wrote on 2022-06-08, 20:48:

Great idea for a project. The only thing with the fan header is alot of fans tend to have a starting voltage of around 6 volts. It's possible that there will be fans that run at 5 volts no problem but I've had alot of fans refuse to start below 6 volts.

just use a 5v fan 😁

Yes that is true. I'm just not sure how prevalent 5 volts fans are versus 12 volt fans.

Thanks :p

chrismeyer6 wrote on 2022-06-08, 21:24:

weedeewee wrote on 2022-06-08, 21:17:

chrismeyer6 wrote on 2022-06-08, 20:48:

Great idea for a project. The only thing with the fan header is alot of fans tend to have a starting voltage of around 6 volts. It's possible that there will be fans that run at 5 volts no problem but I've had alot of fans refuse to start below 6 volts.

just use a 5v fan 😁

Yes that is true. I'm just not sure how prevalent 5 volts fans are versus 12 volt fans.

Not really much use in protesting it, because there isn’t much we can do about it.

The socket can only supply 5v or 3.3v so it will either be useful to the user or it won’t.

If it isn’t, then traditional fan powering methods like a molex adapter will be used.

5v fans are easy to order. And adapting them to a 2.54mm fan header is easy.

https://www.amazon.com/Noctua-Cooling-Bearing … 023647929&psc=1

Here is a 40mm 5v fan.

The instructions for this tweaker is going to be rather complicated. I’m thinking of making a separate card that goes with it that you could like double side tape to the inside of the case somewhere. Thoughts?

With three separate jumpers that go to different cpu types for different things. I’m almost thinking of making picture diagrams for each cpu class showing which jumpers to use for which settings.. sheesh this one will almost need a manual.

I could always make a online guide and put the link on the device in text…🤔 hate to do that though.

-register programming (i don't think this is gonna happen, I assume these are usually through software)

It's too bad you don't want to pursue this one.

Is the purpose of this project to bring something new to the table, or just to make up for a shortage of 486 interposers?

Purpose is to bring all the possible hardware mods onto one device that is easy to implement.

It will also raise awareness of the mods themselves. Many people may not even know nods are possible. This will show show which ones are possible and provide a easy way to do them

This first iteration which may split into a motherboard, a shim and a interposer variant will not include a voltage component though. This will be a path finder for that later project.

http://www.pchardwarelinks.com/486pin.htm

More info

Anonymous Coward wrote on 2022-06-09, 14:34:

-register programming (i don't think this is gonna happen, I assume these are usually through software)

It's too bad you don't want to pursue this one.

Is the purpose of this project to bring something new to the table, or just to make up for a shortage of 486 interposers?

It’s not that I don’t want to, it’s that I don’t think I can. Isn’t this done through software? If so wouldn’t it make more sense to try and use automated startup software for this?

If there is a actual pin for these functions then maybe I can research and include it but my understanding is that it’s done from software. Can you provide more info for me if this is false, if I’m operating under a false pretense here maybe we can research, understand and eventually implement it.

https://en.m.wikipedia.org/wiki/Processor_register

Here: read this and tell me if the registers you are talking about are hardware registers

Cyrix cpu register programming should be available in their data books. Normally this happens at the bios level on systems that officially support the cpus, but on older systems you use a command line utility.
I definitely don’t think implementing this feature should be easy, and would require additional logic.

Anonymous Coward wrote on 2022-06-10, 01:20:

Cyrix cpu register programming should be available in their data books. Normally this happens at the bios level on systems that officially support the cpus, but on older systems you use a command line utility.
I definitely don’t think implementing this feature should be easy, and would require additional logic.

Yeah. That’s what I understood. Sorry guys. The tweaker won’t be able to do this 🙁

Desired features update:

-socket 1 amd 133 cpu auto detection (retro and I are researching the cause of this right now)

-voltage 5v->3.3v (voltage taps on interposer to power cpu externally are doable, and a full on voltage interposer later down the road.)

-PGA168 on the bottom, and a PGA237 on top (interposer design will allow user to configure this way or other ways if user wishes)

-cache mode (looks doable)

-blend pin (looks doable)

-Miltiplier adjustments. (Looks doable, but instructions will be complicated)

-fan header (easy stuff but limited to 5 or 3.3v)

-Math co processor (we'll see…)

There is a distinct lack of space btw. So let’s cross our fingers that all this will fit.

Adding the math coprocessor is not worth your time. Those modules are designed specifically for the Cyrix 486S. It's a relatively uncommon CPU that probably nobody wants to run anyway. The only other 168-pin CPU that can work with external 387 is the TI486SXL, and that chip isn't even 486 bus compatible.

Anonymous Coward wrote on 2022-06-10, 04:05:

Adding the math coprocessor is not worth your time. Those modules are designed specifically for the Cyrix 486S. It's a relatively uncommon CPU that probably nobody wants to run anyway. The only other 168-pin CPU that can work with external 387 is the TI486SXL, and that chip isn't even 486 bus compatible.

Okay, sounds good. Wasn’t looking that serious at it anyway. But adding the pads and traces for it might be fine, (you wouldn’t have to install it per se) though I imagine those chips are probably hard to find…

Might be fun to revisit the cache idea one day. But for now lets get a functional basic tweaker working.

I'm not totally sure what the 487S actually is. Maybe it's just a 487DLC with new silkscreen, or maybe it's a special part made just for the 486S. Somebody would have to test to find out. The 487S is rare, but the 487DLC in QFP is common as dirt.

Anonymous Coward wrote on 2022-06-10, 04:05:

Adding the math coprocessor is not worth your time. Those modules are designed specifically for the Cyrix 486S. It's a relatively uncommon CPU that probably nobody wants to run anyway. The only other 168-pin CPU that can work with external 387 is the TI486SXL, and that chip isn't even 486 bus compatible.

Unless I missed something, I think you forgot about the i486SX

Been filling out the pads, nets and playing with the layout some. can I get your guys feedback on clearance issues?

Many things left to adjust, but the device is starting to take shape.
the holes are still set to .016" for a while I was thinking shim style with pres fit for this, after further research I'm seeing a interposer is just gonna have to be the way to go. unless I wanna make three variants for 6 oclock, 9 oclock and 12 oclock for clearance reasons on different motherboards. a motherboard style tweaker may also come of this.

The clearance under the cpu inside the socket has always been kinda scarce but when you take into account blue sockets, it basically makes a shim style impossible. without locating everything oposite the lever or oposite the crank and there are usually clearance issues there.

I'm looking for people to verify these mods before I take this out of alpha.

Need to test the three different multiplier pins. (http://ps-2.kev009.com/eprmhtml/eprmx/h12203.htm)

Need to test the blend pin function (see video from earlier)

Need to test the cache pin function (see video from earlier)

Need to test wt/wb (which is a pin shared with one of the multiplier pins but for different cpu)

need to investigate definitions for j1, s4 and see if they can be tied to the voltage planes

alpha 4

debs3759 wrote on 2022-06-10, 21:24:

Anonymous Coward wrote on 2022-06-10, 04:05:

Adding the math coprocessor is not worth your time. Those modules are designed specifically for the Cyrix 486S. It's a relatively uncommon CPU that probably nobody wants to run anyway. The only other 168-pin CPU that can work with external 387 is the TI486SXL, and that chip isn't even 486 bus compatible.

Unless I missed something, I think you forgot about the i486SX

Nope. I didn't forget that one. Are there any boards out there that allow a 486SX to work with a 387 class FPU? (487SX doesn't count as a proper FPU)

I don't see any suggestion of a 387 from Sphere, he only said math coprocessor. As it's for socket 3, I take that to mean he wants to be able to run the i487 on it's own, which seems perfectly reasonable.