VOGONS


Reply 20 of 45, by mkarcher

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Intel486dx33 wrote on 2020-07-31, 08:11:

5) don't increase your 486dx4-100 CPU voltage past 3v. ( you will damage the chip ).

The usual spec of a 486dx4-100 CPU is 3.3V to 3.6V, with 3.45V being nominal. I guess that's what you mean, but it could be read as "do not exceed 3.0V", which would be wrong. 3.0V is out-of-spec (too low) for any typical 486DX4 cpu.

Reply 21 of 45, by chublord

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Intel486dx33 wrote on 2020-07-31, 08:11:
1) Make sure you have a good battery ( test with multi-meter ) 2) Remove all cards and devices from your motherboard but the vid […]
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chublord wrote on 2020-07-31, 00:22:

I tried it again in my system...and it actually booted once! It showed 100 MHz, but I can't get it to post again. Something doesn't add up.

1) Make sure you have a good battery ( test with multi-meter )
2) Remove all cards and devices from your motherboard but the video card.
3) press down on cache chips to make sure they are seated correctly.
4) double check jumpers.
5) don't increase your 486dx4-100 CPU voltage past 3v. ( you will damage the chip ).
6) check your motherboard with another CPU to make sure everything is working fine with your motherboard.
7) remove all RAM modules but two parity simms. Make sure you are using the correct ram ( Fast Page mode Parity ) or EDO if your motherboard supports it.
8 ) I believe for DX4 the P24D CPU Selection should be "enabled".

Here are the settings form my Gigabyte motherboard VS-486 for reference.
chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://www.motherboards.org/files/manuals/47/486vs8a.pdf

the coin battery has been replaced. Good suggestions. The computer booted with no issues using my original write-through DX4-100 chip. I did try all of the available jumper positions, there aren't that many on this board.

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2

Reply 22 of 45, by CoffeeOne

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chublord wrote on 2020-07-25, 01:21:

Just got a NOS DX4-100 chip but can't get it to post. Anything odd about it or did I just get a bad chip? Tried 3.0V-3.5V, nothing. System boots right up with the old DX4-100 &E chip. System a IBM Valuepoint 466DX2/Dp.

Do some systems not work with the write-back cache (&EW)?

The black bottom looks like a Cyrix Cx486 DX2 to me.

Reply 23 of 45, by chublord

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If this was actually a 5v DX2-66, what is the lowest voltage it would boot up with?

I tried removing all cards, all memory except 8 MB, all IDE drives, etc. I got a blinking cursor once, nothing the other 20+ times I tried. Never posted.

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2

Reply 24 of 45, by Intel486dx33

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chublord wrote on 2020-08-04, 00:30:

If this was actually a 5v DX2-66, what is the lowest voltage it would boot up with?

I tried removing all cards, all memory except 8 MB, all IDE drives, etc. I got a blinking cursor once, nothing the other 20+ times I tried. Never posted.

Make sure your motherboard cache jumper settings are correct.

Reply 25 of 45, by Horun

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Just a add-on: have never had a write-back cache CPU not boot when board is set to write-through. Still think you got a bogus or odd ball cpu that may never work in your IBM board. If you have any other 486 board that supports a DX-100 I would try it in that instead.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. https://archive.org/details/@horun

Reply 26 of 45, by CoffeeOne

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CoffeeOne wrote on 2020-07-31, 16:07:
chublord wrote on 2020-07-25, 01:21:

Just got a NOS DX4-100 chip but can't get it to post. Anything odd about it or did I just get a bad chip? Tried 3.0V-3.5V, nothing. System boots right up with the old DX4-100 &E chip. System a IBM Valuepoint 466DX2/Dp.

Do some systems not work with the write-back cache (&EW)?

The black bottom looks like a Cyrix Cx486 DX2 to me.

If you cannot get your money back, then yes, try it on 5 volts.

But maybe the board just cannot handle Cyrix cpus .....
So test it on 5 volts for a very short time only, like max. 10 seconds (it will not burn immediately) 😀

Reply 27 of 45, by auron

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don't see how this looks like a cyrix, at least from the cx486 dx2 pics i can find, it has that metal stuff at the edges of the bottom cap (solder?) that i don't see on any cyrix model.

what it does resemble is socket 5/7 ceramic pentiums, albeit without any writing on that bottom part...

Reply 28 of 45, by debs3759

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I suspect it is an Intel DX2.

The Intel logo doesn't have the ® after it, which Intel always used. The logo doesn't have the dropped "e", which I think it should have. The die cap is too large for a DX4.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 29 of 45, by Intel486dx33

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chublord wrote on 2020-08-04, 00:30:

If this was actually a 5v DX2-66, what is the lowest voltage it would boot up with?

I tried removing all cards, all memory except 8 MB, all IDE drives, etc. I got a blinking cursor once, nothing the other 20+ times I tried. Never posted.

5v and 33mhz bus.

This 486dx4 chip looks strange. From the labeling to the black belly.

Reply 30 of 45, by chublord

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I'll try it at 5V, 33 MHz FSB and see what happens.

If it doesn't, I'll try removing the die cap and exposing the core to solve the mystery

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2

Reply 31 of 45, by H3nrik V!

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http://www.cpu-world.com/forum/viewtopic.php?t=13445 Wonder if some useful information can be obtained from this thread?

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀

Reply 32 of 45, by chublord

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H3nrik V! wrote on 2020-08-05, 19:52:

http://www.cpu-world.com/forum/viewtopic.php?t=13445 Wonder if some useful information can be obtained from this thread?

Yeah I saw that, was interesting. Unfortunately, nobody responded with test results in that thread.

CPU posted once at 5v and 33 MHz FSB, but locked up right after the memory count. I could not get it to post again. Time to take the die cap off.

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2

Reply 33 of 45, by Anonymous Coward

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Maybe it's really an old 486SX-25. Try changing jumpers to 25MHz bus and SX pinout.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 34 of 45, by auron

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H3nrik V! wrote on 2020-08-05, 19:52:

http://www.cpu-world.com/forum/viewtopic.php?t=13445 Wonder if some useful information can be obtained from this thread?

regarding the SK096 examples in the last post, both the 1999 and 2005 makes have the old logo with dropped e, but the 2005 one has the black die cover like the 2007 one. so everything seems to make sense here as well.

could it be that the gold die cover part they used on 486s for the most part went out of production at some point between 1999 and 2005 and was simply replaced with the black one that they had also been using on pentiums? before OP goes to smash it to pieces, measuring its dimensions might be of interest...

Reply 35 of 45, by Anonymous Coward

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You're right. It does look very much like a Pentium die cap.
But, why doesn't it work the same as a regular DX/4?

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 37 of 45, by chublord

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I figured they might have changed die caps if it was a late production chip. It should be obvious after removing the cap if the die is the right size. But is there any good explanation why this chip would not work in my system, yet my write-thru DX4-100 "&E" works just fine?

If someone else has a motherboard and wants to try it, I'll ship it. If it works you can keep it. Only caveat, if it doesn't work, it should be dissected so we all know for sure.

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2

Reply 38 of 45, by debs3759

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If you are in Europe, I have a 486 system that can test everything except a TI 486SXL2

Message me if that helps.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 39 of 45, by chublord

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I am in the USA (California), sorry for not specifying.

IBM Valuepoint 486 DX4-100, Opti 802G, 50 MHz FSB, Voodoo1+S3 864, Quantum Fireball EX 4.0 GB, Seagate Medalist 1.6 GB, 128 MB FPM, 256k L2