Maybe I misunderstood the plan. I thought that the dip switches would be on the interposer itself, either off to one side or the underside.

I did add this mod to the back of my board. I understand its purpose, but it would be nice to easily toggle it on or off for testing to acquire data for comparison.

Here are some photos of my modification. The caption tape on top of the resistor isn't strictly necessary since ethe joints are strong. But I think it's good to shield it as much as possible from any potential mechanical stress such as a finger pressing against it unintentionally or risking the resistor being nicked on something hard like a brass motherboard standoff.

If someone wanted this mod to be permanent, I think a layer of hot glue would work very well. I'm hesitant to recommend epoxy in these situations, because of difficult or impossible it would be to remove in the future. Hot glue is very strong and can, with some effort, often be removed cleanly. One trick is to use hot glue on top of a layer of Kapton tape. This provides rigidity but also allows easy removal by pulling up the tape.

Yeah basically the idea is to solder this board over that entire area tapping in to a number of socket pins and not only offer the mod you have there, but also a way to disable it and a way to toggle between wt and wb.

As well as several other mods for a range of usses, such as getting tillamooks working and adding ss7 multipliers to socket 5 and 7

And finally offer 3.3v taps so that 3.3v can be added to the pci.

The tyan s1564 appears to have some room for improvement from this mod.

Re: Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

It seems that installing a pull up resistor on bf2 will allow the board to set 4x on tillamooks and possibly other ss7 multipliers on other cpus

Tyan s1564d:
I’ve been doing some Experiments with bf2

I noticed that the top jumper on the bf 0,1 block seems to control bf2 when used with a tillamook with the 0 ohm 330 ohm extended mod.

So I decided to see if I could get 4x to work on my 400gp

So I started by installing a 1.9k resistor here:
No 4x on the cyrix
Next I tried a 1k
No 4x on the cyrix,
Then I tried a 330 ohm
Still no 4x on the cyrix

I’m a little perplexed what I missed, that jumper appears to connect to bf2 but have no pull up. Not sure why it works with modded tillamook but not a cyrix when the resistor is on the motherboard

Hi
Would that BF2 4x mod work with Pentium MMX 233 to force it to run 266?

lukas12p wrote on 2022-03-28, 11:17:

Hi
Would that BF2 4x mod work with Pentium MMX 233 to force it to run 266?

No, the non tillamooks don’t have 4x internally it seems

but on the other side, tillamook doesn't have multi cpu support, right?
(looking for the way to speed up my dual S7 setup with only up to 66 MHz fsb)

Okay!! I figured it out!! Omg, you aren’t going to believe this, but the tillamook was the key,

What are the chances that I would put a modded tillamook in this board and notice this but get this…

That top jumper actually goes to the tillamook bf2 position

So when I duplicated the tillamook bf2 extended mod v3.0 the cyrix and amd chips now respond to that jumper! W00t!

lukas12p wrote on 2022-03-28, 12:36:

but on the other side, tillamook doesn't have multi cpu support, right?
(looking for the way to speed up my dual S7 setup with only up to 66 MHz fsb)

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

Sphere478 wrote on 2022-03-28, 12:52:

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

but what is the point in running one CPU in dual CPU board? 😀

lukas12p wrote on 2022-03-28, 13:02:

Sphere478 wrote on 2022-03-28, 12:52:

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

but what is the point in running one CPU in dual CPU board? 😀

Ah yes, you’ve discovered my conundrum.

But the 3+ is a lot faster.

Okay, so I’m doing more experiments.
Two mobos:
One has bf2 pull up, and tillamook bf2 bridge
The other just has the bf2 bridge.

So far they both seem to behave the same.

As if the pull up isn’t doing anything?

But that bf2 to tillamook bf2 link definitely did something.

lukas12p wrote on 2022-03-28, 13:02:

Sphere478 wrote on 2022-03-28, 12:52:

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

but what is the point in running one CPU in dual CPU board? 😀

testing? 😋

Saving on your electricity bill using only a single CPU for 9x gaming? 😋

I think I see why my 400gp isn’t liking this mod

Here we see cyrix MII,

amd k6,

intel tillamook,

and pentium mmx

It seems cyrix routed something else to that tillamook pin.

Which means to use a cyrix I have to undo the mod. And do it a different way.

Suspa# is interfering with proper operation when using the tillamook bridge.

So this brings up the need for that pcb that I was talking about earlier. The tillamook bridge could be disabled when using it.

Sphere478 wrote on 2022-03-28, 12:52:

Okay!! I figured it out!! Omg, you aren’t going to believe this, but the tillamook was the key, […]
Show full quote

Okay!! I figured it out!! Omg, you aren’t going to believe this, but the tillamook was the key,

What are the chances that I would put a modded tillamook in this board and notice this but get this…

That top jumper actually goes to the tillamook bf2 position

So when I duplicated the tillamook bf2 extended mod v3.0 the cyrix and amd chips now respond to that jumper! W00t!

lukas12p wrote on 2022-03-28, 12:36:

but on the other side, tillamook doesn't have multi cpu support, right?
(looking for the way to speed up my dual S7 setup with only up to 66 MHz fsb)

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

This might actually be useful for those who want to build a time machine out of more modern parts. How hot does it get at 50 Mhz?

Kahenraz wrote on 2022-03-28, 14:31:

Sphere478 wrote on 2022-03-28, 12:52:

Okay!! I figured it out!! Omg, you aren’t going to believe this, but the tillamook was the key, […]
Show full quote

Okay!! I figured it out!! Omg, you aren’t going to believe this, but the tillamook was the key,

What are the chances that I would put a modded tillamook in this board and notice this but get this…

That top jumper actually goes to the tillamook bf2 position

So when I duplicated the tillamook bf2 extended mod v3.0 the cyrix and amd chips now respond to that jumper! W00t!

lukas12p wrote on 2022-03-28, 12:36:

but on the other side, tillamook doesn't have multi cpu support, right?
(looking for the way to speed up my dual S7 setup with only up to 66 MHz fsb)

The best way is a k6-3+ 400mhz using the 2x multi setting

Check it out: I got the 400gp to 1x multi!

This might actually be useful for those who want to build a time machine out of more modern parts. How hot does it get at 50 Mhz?

I’m not convinced that’s the 1x multiplier. Post froze right there whenever it showed that. And I wasn’t able to get to 1x on my ss7 mobo.. I think that may actually be the cpu flipping out because that’s got the suspa# pin pulled high or low. And I think it may be screwing with something.

I pulled all the links/resistors off.

To do this right I think the pcb should instead of having a bridge, it should simply be set up with four bf pins and a note should be on tillamook bf2 that it’s for tillamook only and not to be enabled on cyrix.

I'm tryin to learn kicad here.. it's not going so well but I got some stuff done

I gotta figure out:
-how to add three SMD dip blocks
-how to make the holes bigger and de plate some of them
-how to do silkscreen

double check my wiring here.. (haven't updated the mspaint diagram to reflect design changes)

features:
-vcc2 (core) tap for those wishing to try and take control of socket 7 vrm
-vcc3 (I/O 3.3v) tap for those wishing tp power a pci slot with the I/O vrm on a dual plane cpu
-bf0 pull high/disable with switch
-bf0 pull low/disable with switch
-bf1 pull high/disable with switch
-bf1 pull low/disable with switch
-bf2 pull high/disable with switch
-bf2 pull low/disable with switch
-tillamook bf2 pull high/disable with switch
-tillamook bf2 pull low/disable with switch
-tillamook voltage detect pin relocate with resistor pad and disable switch
-tillamook BRYD# pin relocate with resistor pad and disable switch (cache)
-tillamook ADB# pin relocate with resistor pad and disable switch (cache)
-WT/WB pin pull high with resistor and disable switch (asus p5a and others)
-WT/WB pin pull low with resistor and disable switch (asus p5a and others)
-vss (gnd) taps (for whatever)

it seems like I've thought of everything here...

here is what I have so far, I'm told I.m doing it wrong 🤣

I included a footprint of a 12 position switch. I'm thinking three separate switch blocks are best though

Edit:
here I finished the schematic in ms paint 🤣

I noticed I had pin ak2 tapped for some reason. I blacked it out now

this is looking pretty good as far as routing and layout goes... spacing may need tweaked though

edit 2: thoughts on resistors...
resistor arrays while nice I think are not ideal as end users may wish to try different values

wt/wb resistor value: pull up 1k has been shown to work on p5a with 1kohm I suspect that this may not wort on all mobos though and I don't know what pull down should be.

all four bf pins: pull down I've seen 25 ohm, intel specs 500 ohm or less. pull up I've seen 330 and 2200 ohm working

tillamook vss detect in the tillamook thread this is 0 ohm and shown to work, but with a different cpu it may cause a short. suggest starting with 2200 ohm and dropping down till it works

tillamook cache mods one and 2 in the tillamook thread this is 0 ohm and shown to work, but with a different cpu it may cause a short. suggest starting with 2200 ohm and dropping down till it works

is there anything here that we can add?

1KEN#, CACHE# Cache pins may be for enabling or disabling cache. It could be added.
2
3SMI#, SMIACT# could be used to set SMI (No Idea of this would help with anything)
4
5BHOLD, idk if this can be activated by a pin but some mobos have a special bus option for cyrix chips.
6
7There are several things listed for dual processor functions on intel,
8
9One in particular interest. Is how might we be able to set redundant processor mode. Perhaps by enabling of a signal on one of these pins?

Is there any combination of switches that could damage the CPU or the motherboard?

Kahenraz wrote on 2022-03-29, 14:45:

Is there any combination of switches that could damage the CPU or the motherboard?

-The tillamook bf2 mod goes to a different pin on cyrix but with proper resistors doesn’t seem to hurt anything.

The other bf mods if properly resistored shouldn’t hurt anything in any conbination

The wt/wb it is assumed the same would be true as bf but not as sure, because I suspect you’ll have to use really low resistors to over ride some motherboards. I think it will be fine though so long as you choose your resistor wisely

The voltage detect pin and the tillamook cache mods. I don’t know, I expect the motherboard probably won’t care but it may be possible for some cpus to be using those pins for something else, one should enable them on a tillamook only. They serve no purpose on any other cpu. We may be able to test which resistor values work on tillamook and recommend a high value resistor that still works on tillamook but adds safety on others. (Though others may not even care, would have to test to find out, but there is no point, we test for highest resistor, then check other cpus for issues, with resistor there should be no issues)

Once the board is made I’d like to see people populate the resistors with high values and report the highest value that worked. The higher the value the safer it is.

See my post about resistor values.

So far I haven’t damaged anything with these mods, nor have I heard of someone doing so. The resistors are a important safety device for this.

I'm sure I have this all messed up somehow..

still can't figure out :

how to turn those holes into non plated holes that are as large as the original pads

how to turn the pads/holes being used into plated holes the size of the original pads

how to make castellated holes

I think the stuff may be on the wrong side..

ant pcb wizards able to take a look and trim the edges?