Sphere478 wrote on 2023-12-12, 18:31:

Yes, I didn’t figure it was worth washing off free flux till the job was done haha

Thats not how flux works.. It only can be used one time. That is doesnt work great anymore and you have to apply new again.

watson wrote on 2024-01-27, 16:50:

I was referring to the other diode that has not been removed.
Removing the one for the charging circuit is fine.

The second diode on the trace to external battery +(positive) terminal is to prevent back-charging of the on-board rechargeable battery from the ext. battery and it is completely useless if no ext. battery will be connected ever. I already wrote about this.

The motherboard arrived!!

It looks absolutely amazing! Very nice job Tony359!

The upgrades and testing has already begun! :p

16mb x4 4mb x 4
Galapu’s AnyClk device for setting crystal speed (set to stock RN)
It would be cool to get the weitek for this. Though idk if it would be utilized with a dx processor. Might show two numerical units. That would be cool?

Okie dokie, the board is definitely working! 😀

First thing I like to so with a new build is confirm max ram.

The maximum supported ram of this motherboard is 8 sticks of 9 chip 4mb for a max total of 32mb (w/parity bit) unsure if it uses the parity bit, but the sticks do work in the board when 9 chips per module are present. Edit: parity option is present in bios.

What does not work ram wise:
2 or 3 chip 4mb sticks do not work. 16mb 8 or 9 chip sticks do not work.

I have about 10 486 dx2 cpus and I binned them based on which ones would post at the highest frequency. Eventually I ended up with a 1993 cpu which was able to post at about 45 fsb.

It of course wasn’t stable. So I kept dropping it till I got to 40 mhz at which point the system would boot and run doom/speedsys seemingly stable.

I have added a cooler to the cpu now 😀

So chkcpu is reporting the cpu has WB. Can that be right? Didn’t realize dx2 came with that.

There are some jumpers near the cpu, they may go to that register… 🤔

Hi, I follow your posts with interest, and also Tony359's videos, for my part, I don't have much time to work on the old hardware, but I have some MB 486s that I could complete the repairs in the near future, watching the repair video of yours motherboard, I realize that I am not equipped for some jobs, I hope soon to get some things that will allow me to do more professional work, at the moment I am not able to do track soldering or chip replacement.
The DX2-83 is interesting, but I was wondering if you wanted to get higher frequencies?

Late model DX2/4's with "&EW" in the model name are Write-Back

Sphere478 wrote on 2024-02-03, 01:53:

The upgrades and testing has already begun! :p […]
Show full quote

The upgrades and testing has already begun! :p

16mb x4 4mb x 4
Galapu’s AnyClk device for setting crystal speed (set to stock RN)
It would be cool to get the weitek for this. Though idk if it would be utilized with a dx processor. Might show two numerical units. That would be cool?

80MB of RAM in a mainboard of that age? Amazing!
But I am afraid that the cacheable are of that board is max 64MB. So check how large the cacheable area is and then adjust the RAM size.
If I am right with the 64MB it is easy, just don't use the 4 times 4MB.
You are using already the maximum amount of L2 cache which seems to be 256kB, so upgrading L2 (in order to increase cacheable area) is no option.

Forget about the Weitek 4167.
First, it is unobtainable.
Then it is not compatible to the i486 FPU, you need special software (some super old CAD software) to utilize it.
And beginning with a DX2-66, the builtin FPU will outperform the Weitek 4167 running at 33MHz anyway.
The only point of having a Weitek 4167 is to collect it, because it is super rare. But not of any practical use.

PC@LIVE wrote on 2024-02-03, 07:42:

Hi, I follow your posts with interest, and also Tony359's videos, for my part, I don't have much time to work on the old hardware, but I have some MB 486s that I could complete the repairs in the near future, watching the repair video of yours motherboard, I realize that I am not equipped for some jobs, I hope soon to get some things that will allow me to do more professional work, at the moment I am not able to do track soldering or chip replacement.
The DX2-83 is interesting, but I was wondering if you wanted to get higher frequencies?

It seems that that is as high as I can go with the stuff I currently have.

I could purchace a POD, or a cyrix 120 to go faster. The cyrix would need a interposer which I didndesign a while back. (Pcb projects) also calamitylime has one that has less tweaks but a onboard regulator.

In any case. The dx2s I have seem to be capped around there. 80mhz

I am looking around and it seems that they may have made a faster version of the dx2 I’m not sure what the difference between it and a 486 overdrive is though maybe there isn’t a difference?

CoffeeOne wrote on 2024-02-03, 16:07:

80MB of RAM in a mainboard of that age? Amazing! But I am afraid that the cacheable are of that board is max 64MB. So check how […]
Show full quote

Sphere478 wrote on 2024-02-03, 01:53:

The upgrades and testing has already begun! :p […]
Show full quote

The upgrades and testing has already begun! :p

16mb x4 4mb x 4
Galapu’s AnyClk device for setting crystal speed (set to stock RN)
It would be cool to get the weitek for this. Though idk if it would be utilized with a dx processor. Might show two numerical units. That would be cool?

80MB of RAM in a mainboard of that age? Amazing!
But I am afraid that the cacheable are of that board is max 64MB. So check how large the cacheable area is and then adjust the RAM size.
If I am right with the 64MB it is easy, just don't use the 4 times 4MB.
You are using already the maximum amount of L2 cache which seems to be 256kB, so upgrading L2 (in order to increase cacheable area) is no option.

Forget about the Weitek 4167.
First, it is unobtainable.
Then it is not compatible to the i486 FPU, you need special software (some super old CAD software) to utilize it.
And beginning with a DX2-66, the builtin FPU will outperform the Weitek 4167 running at 33MHz anyway.
The only point of having a Weitek 4167 is to collect it, because it is super rare. But not of any practical use.

I have 20mb in it now. 32 mb is possible the first test config did not work 16mb x 4 + 4mb x 4 didn’t work

Sphere478 wrote on 2024-02-03, 05:58:

I have about 10 486 dx2 cpus and I binned them based on which ones would post at the highest frequency. Eventually I ended up with a 1993 cpu which was able to post at about 45 fsb.

It of course wasn’t stable. So I kept dropping it till I got to 40 mhz at which point the system would boot and run doom/speedsys seemingly stable.

I have added a cooler to the cpu now 😀

The speedsys graph does not look like, that the L1 is running in WB mode.
But check first for the cacheable area (see my other posting) and then test everything again.
EDIT: with only 20MB of RAM there will be 99.9% no problem with the cachable area.

Sphere478 wrote on 2024-02-03, 16:10:

It seems that that is as high as I can go with the stuff I currently have. […]
Show full quote

PC@LIVE wrote on 2024-02-03, 07:42:

Hi, I follow your posts with interest, and also Tony359's videos, for my part, I don't have much time to work on the old hardware, but I have some MB 486s that I could complete the repairs in the near future, watching the repair video of yours motherboard, I realize that I am not equipped for some jobs, I hope soon to get some things that will allow me to do more professional work, at the moment I am not able to do track soldering or chip replacement.
The DX2-83 is interesting, but I was wondering if you wanted to get higher frequencies?

It seems that that is as high as I can go with the stuff I currently have.

I could purchace a POD, or a cyrix 120 to go faster. The cyrix would need a interposer which I didndesign a while back. (Pcb projects) also calamitylime has one that has less tweaks but a onboard regulator.

In any case. The dx2s I have seem to be capped around there. 80mhz

I am looking around and it seems that they may have made a faster version of the dx2 I’m not sure what the difference between it and a 486 overdrive is though maybe there isn’t a difference?

CoffeeOne wrote on 2024-02-03, 16:07:

80MB of RAM in a mainboard of that age? Amazing! But I am afraid that the cacheable are of that board is max 64MB. So check how […]
Show full quote

Sphere478 wrote on 2024-02-03, 01:53:

The upgrades and testing has already begun! :p […]
Show full quote

The upgrades and testing has already begun! :p

16mb x4 4mb x 4
Galapu’s AnyClk device for setting crystal speed (set to stock RN)
It would be cool to get the weitek for this. Though idk if it would be utilized with a dx processor. Might show two numerical units. That would be cool?

80MB of RAM in a mainboard of that age? Amazing!
But I am afraid that the cacheable are of that board is max 64MB. So check how large the cacheable area is and then adjust the RAM size.
If I am right with the 64MB it is easy, just don't use the 4 times 4MB.
You are using already the maximum amount of L2 cache which seems to be 256kB, so upgrading L2 (in order to increase cacheable area) is no option.

Forget about the Weitek 4167.
First, it is unobtainable.
Then it is not compatible to the i486 FPU, you need special software (some super old CAD software) to utilize it.
And beginning with a DX2-66, the builtin FPU will outperform the Weitek 4167 running at 33MHz anyway.
The only point of having a Weitek 4167 is to collect it, because it is super rare. But not of any practical use.

I have 20mb in it now. 32 mb is possible the first test config did not work 16mb x 4 + 4mb x 4 didn’t work

You reply very fast 😁
4 times 16MB did not work either?

CoffeeOne wrote on 2024-02-03, 16:14:

Sphere478 wrote on 2024-02-03, 05:58:

I have about 10 486 dx2 cpus and I binned them based on which ones would post at the highest frequency. Eventually I ended up with a 1993 cpu which was able to post at about 45 fsb.

It of course wasn’t stable. So I kept dropping it till I got to 40 mhz at which point the system would boot and run doom/speedsys seemingly stable.

I have added a cooler to the cpu now 😀

The speedsys graph does not look like, that the L1 is running in WB mode.
But check first for the cacheable area (see my other posting) and then test everything again.

I believe you are correct. I need to figure out how to enable it.

Unfortunately last nights tests ended in a audible explosion which I heard from the other room.

My projector lamp, fortunately not the motherboard 😀

If anyone has the data sheet on the dx2 WB chip, LMK. Gonna studdy it and see what tweaks and mods can be done.

I may build my socket 1/2/3 tweaker for this project. Seems like it may be a good candidate for it.

CoffeeOne wrote on 2024-02-03, 16:16:

Sphere478 wrote on 2024-02-03, 16:10:

It seems that that is as high as I can go with the stuff I currently have. […]
Show full quote

PC@LIVE wrote on 2024-02-03, 07:42:

Hi, I follow your posts with interest, and also Tony359's videos, for my part, I don't have much time to work on the old hardware, but I have some MB 486s that I could complete the repairs in the near future, watching the repair video of yours motherboard, I realize that I am not equipped for some jobs, I hope soon to get some things that will allow me to do more professional work, at the moment I am not able to do track soldering or chip replacement.
The DX2-83 is interesting, but I was wondering if you wanted to get higher frequencies?

It seems that that is as high as I can go with the stuff I currently have.

I could purchace a POD, or a cyrix 120 to go faster. The cyrix would need a interposer which I didndesign a while back. (Pcb projects) also calamitylime has one that has less tweaks but a onboard regulator.

In any case. The dx2s I have seem to be capped around there. 80mhz

I am looking around and it seems that they may have made a faster version of the dx2 I’m not sure what the difference between it and a 486 overdrive is though maybe there isn’t a difference?

CoffeeOne wrote on 2024-02-03, 16:07:

80MB of RAM in a mainboard of that age? Amazing! But I am afraid that the cacheable are of that board is max 64MB. So check how […]
Show full quote

80MB of RAM in a mainboard of that age? Amazing!
But I am afraid that the cacheable are of that board is max 64MB. So check how large the cacheable area is and then adjust the RAM size.
If I am right with the 64MB it is easy, just don't use the 4 times 4MB.
You are using already the maximum amount of L2 cache which seems to be 256kB, so upgrading L2 (in order to increase cacheable area) is no option.

Forget about the Weitek 4167.
First, it is unobtainable.
Then it is not compatible to the i486 FPU, you need special software (some super old CAD software) to utilize it.
And beginning with a DX2-66, the builtin FPU will outperform the Weitek 4167 running at 33MHz anyway.
The only point of having a Weitek 4167 is to collect it, because it is super rare. But not of any practical use.

I have 20mb in it now. 32 mb is possible the first test config did not work 16mb x 4 + 4mb x 4 didn’t work

You reply very fast 😁
4 times 16MB did not work either?

Scroll back. I described what does and doesn’t work. 3 chip 4mb is no go 9 chip 16 mb is no go

Sphere478 wrote on 2024-02-03, 16:19:

CoffeeOne wrote on 2024-02-03, 16:16:

Sphere478 wrote on 2024-02-03, 16:10:

It seems that that is as high as I can go with the stuff I currently have. […]
Show full quote

It seems that that is as high as I can go with the stuff I currently have.

I could purchace a POD, or a cyrix 120 to go faster. The cyrix would need a interposer which I didndesign a while back. (Pcb projects) also calamitylime has one that has less tweaks but a onboard regulator.

In any case. The dx2s I have seem to be capped around there. 80mhz

I am looking around and it seems that they may have made a faster version of the dx2 I’m not sure what the difference between it and a 486 overdrive is though maybe there isn’t a difference?

I have 20mb in it now. 32 mb is possible the first test config did not work 16mb x 4 + 4mb x 4 didn’t work

You reply very fast 😁
4 times 16MB did not work either?

Scroll back. I described what does and doesn’t work. 3 chip 4mb is no go 9 chip 16 mb is no go

Right. Sorry, I did not read that part.

OK about L1 WB: As user MikeSG already wrote, you can check very easy if your DX2 is a WB type by just reading the markings.
But I don't think there is any 486 board with only ISA slots, which supports L1 WB for the 486 CPU.
https://theretroweb.com/chipset/documentation … f2936617240.pdf
I think the WB in this description refers to the L2 cache, so you don't need to check if you have a &EW CPU, it will not make any difference.
I think the chipset was really state of the art, when it was released: 1991! Amazing. Also cacheable area is covered in this pdf in detail.
Max. mem is 64MB by the way, but maybe you need some weird modules to get it.

EDIT: Sorry sent too fast again 😁
If I read the pdf correctly, 64MB you can have with 4 banks only. Your board has 2 banks of RAM, so max. is 32MB.

Interesting about the 64mb..

To get there you would need 16mb x4 which does not work. Odd. I suspect that retro web sinply has the wrong data. Unless as you say, some strange modules.

It may be that chipset supports up to 64mb if mobo has enough simm slots (16)

I did note that the bios says cachable area up to 64mb In options.

So the mobo its self won’t support wb? Even if I enable it in register on cpu?

Sphere478 wrote on 2024-02-03, 16:52:

Interesting about the 64mb.. […]
Show full quote

Interesting about the 64mb..

To get there you would need 16mb x4 which does not work. Odd. I suspect that retro web sinply has the wrong data. Unless as you say, some strange modules.

It may be that chipset supports up to 64mb if mobo has enough simm slots (16)

I did note that the bios says cachable area up to 64mb In options.

So the mobo its self won’t support wb? Even if I enable it in register on cpu?

Yes, 4 banks = 16 slots of 30 pin.

About L1 WB: It is a chipset thing. L1 WB must be supported by the chipset.

That's a shiny motherboard 😀

Very glad it made it there safely and very happy to see it in good hands being properly used!

tony359 wrote on 2024-02-04, 17:48:

That's a shiny motherboard 😀

Very glad it made it there safely and very happy to see it in good hands being properly used!

I still can't believe I'm seeing it alive. Makes me glad I spent $10 on it on eBay years ago xD ($30 but there were two other boards with it)