VOGONS


First post, by lihinian

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I figured this question might get more answers here.

From my other topic: Tulip Vision Line DC 486dx TC38 Restoration [Update 5] Finished
"Can anyone see if this motherboard has L2 cache?
Here's a high res picture https://imgur.com/0MC4Pod

On this site it says it has none: http://stason.org/TULARC/pc/motherboards/T/TU … DC-DT-TC38.html
Which I find hard to believe, why put in a rather awesome GD5428 only to have it hampered by the lack of cache?"

Edit: Fixed broken link

Last edited by lihinian on 2018-02-22, 14:32. Edited 1 time in total.

Reply 2 of 21, by lihinian

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Thanks!
With this heldback, will this computer profit at all from installing a 486dx 75mhz?
Or might I aswell leave it out?
I was hoping to turn this computer into an all capable dos machine. Will upgrading from 8 to 20ram even make a difference?

I'd like to play Doom,Rott,Heretic and maybe some Doom II... can i kiss this dream goodbye?

Reply 4 of 21, by derSammler

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L2 cache does not have such a huge impact on speed on a 486. E.g. a DX4/100 without L2 performs similar to a DX2/80 with L2 cache. So yours will be somewhere between a DX2/50 and DX2/66. Problem with the DX4/75 however is its external clock of just 25 MHz. Better get a DX4/100 that runs with 33 MHz externally - if you can and if the board supports that CPU.

Reply 5 of 21, by Skyscraper

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I'm pretty sure the DX4/75 overdrive will run at 100 MHz without issue if your board has support for the 33MHz FSB setting. I doubt Intel had to do any "binning" when it comes to their DX4 CPUs. If you don't yet own the overdrive then buying the 100 MHz one is the safest bet regardless if it ends up running at 75 or 100 MHz.

Looking at the Stason page (your link is broken btw) I can not see any FSB selecton jumpers so check to see if you find a 25MHz or 50MHz oscillator on the motherboard and if it's soldered or in a socket.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 6 of 21, by Skyscraper

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I now see the picture link you posted, I blame the dirty screen on my notebook at work. 😁

No 25MHz or 50MHz oscillator it seems.

I would try to move the "J17" jumper to the other position and see what happens, perhaps that is the setting for 33 MHz FSB?

The "J18" jumper is for disabling the soldered "PQFP" CPU when using an overdrive model that dosn't do this automagicly if I interpret the jumper table correctly. As you do not have any PQFP CPU soldered on your board you can ignore this jumper completly.

The motherboard is supposed to support 33 MHz FSB but the Stason page dosn't tell you how, it's either the J17 jumper or hardwired from the factory. 😜

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 7 of 21, by lihinian

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amadeus777999 wrote:

The board is not geared towards enthusiasts. Have you tested it with speedsys?

Not yet, I'm picking up an old crt soon.
I also have this other situation with the cmos battery,led and pc speaker (see my other topic). I dont even know if it will boot without them connected.

Skyscraper wrote:

I'm pretty sure the DX4/75 overdrive will run at 100 MHz without issue if your board has support for the 33MHz FSB setting. I doubt Intel had to do any "binning" when it comes to their DX4 CPUs. If you don't yet own the overdrive then buying the 100 MHz one is the safest bet regardless if it ends up running at 75 or 100 MHz.

Looking at the Stason page (your link is broken btw) I can not see any FSB selecton jumpers so check to see if you find a 25MHz or 50MHz oscillator on the motherboard and if it's soldered or in a socket.

I already purchased the DX4/75. At least I got it cheap. DX4/100 go for a fortune.
But wait, then would it still be better to leave in the 33i?
or even get a reasonably priced dx2/66 which would go down to 50Mhz which also runs at an internal 33Mhz? Please correct me if I'm wrong.

d8t9d0l.png
I believe this is the oscillator. How do I know if it's 25 or 50MHz?

Maybe I need to repurpose my idea for this computer.
Use it for platform games and adventures instead. Which is what I wil mainly use it for anyway.

Last edited by lihinian on 2018-02-22, 16:10. Edited 1 time in total.

Reply 8 of 21, by lihinian

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Skyscraper wrote:
I now see the picture link you posted, I blame the dirty screen on my notebook at work. :D […]
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I now see the picture link you posted, I blame the dirty screen on my notebook at work. 😁

No 25MHz or 50MHz oscillator it seems.

I would try to move the "J17" jumper to the other position and see what happens, perhaps that is the setting for 33 MHz FSB?

The "J18" jumper is for disabling the soldered "PQFP" CPU when using an overdrive model that dosn't do this automagicly if I interpret the jumper table correctly. As you do not have any PQFP CPU soldered on your board you can ignore this jumper completly.

The motherboard is supposed to support 33 MHz FSB but the Stason page dosn't tell you how, it's either the J17 jumper or hardwired from the factory. 😜

Didn't see your new reply, was busy typing my previous answers 😜
I will try out the J17 jumper setting, thanks for the tip.

Reply 9 of 21, by Skyscraper

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If you already have a 486 DX33 as you write in your other thread then your motherboard is already running at 33 MHz FSB. There is no need to change anything to run a DX2/66 at 66 MHz or a DX4 overdrive at 100 MHz.

I just thought you had a 25 MHz CPU as you bought a 75 MHz DX4 and I presumed it was an overdrive as that is what your system needs. This is why "cross posting" and starting more than one thread about the same issue/system isn't the best idea. People* are too lazy to read linked threads so making sure all relevant information is noted in the thread where you ask a question is always a good idea.

A non overdrive DX4/75 (or DX4/100 för that matter) will not work (or it will but it will run hot and perhaps die after a while) as your board probably is 5V only and the non overdrive DX4 is a 3.3V CPU.

If the DX4 you already bought isn't an overdrive and you don't want to spend much just get an Intel 486 DX/2 66 CPU. With the DX2 Doom will be playable even without cache but it won't be as smooth as it would be with a DX4 Overdrive @100 Mhz. The DX4/100 Overdrive should cost about $40 shipped which in my mind is affordable.

If the DX4/75 you bought is an overdrive I think it's likely it will be able to run at 100 MHz without any issues. Just plug it in and try it out.

I still think the J17 jumper could be for setting 25 or 33 MHz FSB.

*with people I mean my self...

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 10 of 21, by lazibayer

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Your board has an ICD2023SC-2 chip as the clock generator. It's trickier than most clock generator chips at that time because it can work under "selection" and "programmable" modes, and there is no explicit jumper on your board.
Under selection mode, it functions as regular clock generator and gives a range of bus speed from 20 to 100MHz:

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Under programmable mode things get interesting yet complicated. Please refer to its datasheet for details.

You can probably determine its functioning mode and modifying its frequency output with respect to its pinout.

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Reply 12 of 21, by Skyscraper

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To translate to plain english what lazibayer just wrote.

Your motherboard is stuck at the FSB it was set to at the factory (33 MHz) unless you do a complicated hardware mod to switch the clock generator over to "selection" mode or reprogram the thingy that talks to the clock generators serial interface and asks for P121 Q52 because ((2x14.31818)x(121/52))/2 = 33.32 MHz or something like that... totally logical... perhaps I failed with my "translation"... 😀

If you are really lucky there could be a FSB setting in the BIOS as derSammler writes but I think if it's the BIOS who talks to the clock chip that setting isn't accessible to the user. I find it just as likely that there is some little GAL chip or the like pulling the strings.

You can still try the J17 jumper... perhaps the clock generator IS in "selection mode" already but with only two choices avialible... I doubt that jumper can hurt anything anyhow. Or you can just forget about the whole FSB issue as the board is already running at the preferable 33 MHz FSB setting.

And again, make sure that your DX4 is an Overdrive CPU with unboard VRM circuitry before you use it. A normal Intel DX4 could take damage from beeing used on a 5V only motherboard as it's made for 3.3V.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 13 of 21, by lihinian

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Many thanks for the great abundance of insight and information. Truly a goldmine.
In the future I wil refrain from cross posting. Guess I was a little too eager to get some clarity.

The DX4/75 I bought is the Overdrive ODPR variant, which is a swap-in replacement for the stock processor.
If I'm getting this right... the dx4/75 will probably function like the dx4/100 would without any tinkering?

About the other situation:
The 10 pin connector which connected to a circuit with a led, and from there connected to a cmos battery holder and also the pc speaker. (all broken and corroded)
Does this mean I just have to trial and error and find which 2 +/- pins I need for led, which 2 for the speaker, and which 2 for the cmos?
What I dont get is the 3 pins for the led. Can someone shed some light on this? 😀
plmpieX.jpg?1
nJ4aT5a.jpg?1

Reply 14 of 21, by jamesp15

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lihinian wrote:
Many thanks for the great abundance of insight and information. Truly a goldmine. In the future I wil refrain from cross posting […]
Show full quote

Many thanks for the great abundance of insight and information. Truly a goldmine.
In the future I wil refrain from cross posting. Guess I was a little too eager to get some clarity.

The DX4/75 I bought is the Overdrive ODPR variant, which is a swap-in replacement for the stock processor.
If I'm getting this right... the dx4/75 will probably function like the dx4/100 would without any tinkering?

About the other situation:
The 10 pin connector which connected to a circuit with a led, and from there connected to a cmos battery holder and also the pc speaker. (all broken and corroded)
Does this mean I just have to trial and error and find which 2 +/- pins I need for led, which 2 for the speaker, and which 2 for the cmos?
What I dont get is the 3 pins for the led. Can someone shed some light on this? 😀
plmpieX.jpg?1
nJ4aT5a.jpg?1

Dual color LED, probably Red and Green, with a (probably) common cathode setup if that middle pin goes to a ground/-(negative) connection.

Should be able to trace it all out with a Multimeter in continuity or ohms mode.

Reply 15 of 21, by Skyscraper

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The DX4/75 Overdrive ODPR probably works just fine at 100 MHz, just drop it in and try it out! 😀

It won't hurt to make sure there are some sort or air flow around the CPU area of the motherboard by adding a low RPM fan directed twords the CPU. Space can be an issue and I dont think it's cruicial as the DX4 isn't known for running very hot.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 16 of 21, by tabm0de

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I Have a Tulip also, almost the same as yours but with different mb, sadly it won’t do you any good with overdrive if l2 cache don’t exist I think, you can check my old project here on vogons:

[UPDATE 4 / DONE] The journey of Tulip Vision Line DC 486sx TC35

saw after posting that you did comment in my old post 😉

Ye its right you have a "new" board, and who knows it could be better then what i had 😉 since your board dont have any sx cpu and the model is 33, you would problebly use overdrive dx4 100 instead of 75 or overdrive dx2 66.

naa, nothing yet...

Reply 17 of 21, by Skyscraper

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From my experience L2 cache on a 486 motherboard only adds about 10% performance in games.

In some memory intensive benchmarks cache can double the performance though.

The DX4 overdrive @100 with its 16kB L1 cache should be a decent performer even without L2 cache, fast enough for DOOM for sure.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 18 of 21, by lihinian

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jamesp15 wrote:

Dual color LED, probably Red and Green, with a (probably) common cathode setup if that middle pin goes to a ground/-(negative) connection.
Should be able to trace it all out with a Multimeter in continuity or ohms mode.

Cool, now I can work this out hopefully. Is this what I'm looking for? https://www.ebay.ca/itm/20pcs-5mm-Dual-Bi-Col … 2wAAOSwjk9ZWpKW

Skyscraper wrote:

It won't hurt to make sure there are some sort or air flow around the CPU area of the motherboard by adding a low RPM fan directed twords the CPU. Space can be an issue and I dont think it's cruicial as the DX4 isn't known for running very hot.

I will need a small fan to fit it in there, and maybe use tie-wraps to attach it somewhere. Will a 12V fan be fine for this mobo?
Got my eyes on this one: https://www.ebay.nl/itm/40mm-2Pin-12V-PC-CPU- … 353.m1438.l2649

tabm0de wrote:

saw after posting that you did comment in my old post 😉

Ye its right you have a "new" board, and who knows it could be better then what i had 😉 since your board dont have any sx cpu and the model is 33, you would problebly use overdrive dx4 100 instead of 75 or overdrive dx2 66.

Great to see you in this thread, how's your tulip doing these days?
While you're here: Can you please tell me which method and paint you used for repainting your case? 😊
I might use some peroxide for the front panel, but it looks okay enough already.

Reply 19 of 21, by jamesp15

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lihinian wrote:
jamesp15 wrote:

Dual color LED, probably Red and Green, with a (probably) common cathode setup if that middle pin goes to a ground/-(negative) connection.
Should be able to trace it all out with a Multimeter in continuity or ohms mode.

Cool, now I can work this out hopefully. Is this what I'm looking for? https://www.ebay.ca/itm/20pcs-5mm-Dual-Bi-Col … 2wAAOSwjk9ZWpKW

If that center pin on the circuit board does go to a ground/-/negative, then the LED you linked to should work in its place. With it being chained to another pin I assume it is but all I can do is assume on that part. If that center pin goes to a +/positive voltage you would need a Common Anode LED.

Voltmeter set to Ohms or Continuity to with one probe held onto that (middle of the 3) pin and another held onto a _known_ ground (the metal around a screw hole is a good place, exposed metal parts like a back panel jack housing is usually another, or the negative pin on the battery) would tell you, if it beeps in continuity or if you get a low ohms reading its ground/cathode so it would be a Common Cathode. Can also try between the other 2 pins and a known ground, should get a really high ohms reading OR no reading at all if its a Common Cathode.

If the reverse of the above paragraph is true, then its a Common Anode LED. (as in if the middle pin shows no or really high ohms to ground and the other 2 pins show low ohms/beep on continuity it is a Common Anode)

Depending on multimeter, the Ohms setting might be more useful, the Continuity setting on some multimeters has a too low threshold to "beep" on some circuit layouts (for example might only been under 1 ohm or such when, when 10 ohms or such would still be OK as a circuit.)

I cant say for sure what would constitute a "low" ohms reading there might be (should be) a current limiting resistor in series with the LED, and could well be other circuitry and even the length of the motherboard traces make it so its not a "fixed" number I could give. Your looking for the pin with the lowest resistance to ground of the 3 if its Common Cathode (or the 2 with the lowest to ground if its Common Anode)

Hope that is not confusing or insulting, I am not sure of your level of comfort with a multimeter/etc.