Sorry, dude, but from what you describe you did this could be anything.
First you should never run a CPU with a double digit (or higher) TDP without a heatsink or at least some thermal mass to draw heat away from the silicon die. The Coppermine CPUs do have some thermal protection but with a little bad luck you can still fry your setup. Also heat degrades any CPU even if it doesn't kill it right away. A small cooler is better than no cooler for a test.
Second when taking apart a machine all sorts of problems may arise which will make troubleshooting (especially remote troubleshooting) very hard.
My first suggestion is to restore the last working configuration, in the process visually inspect the system, reseat all components and clear your CMOS, then try powering the machine up again.
Fingers crossed!

Doornkaat wrote on 2020-08-10, 17:28:

Sorry, dude, but from what you describe you did this could be anything. First you should never run a CPU with a double digit (o […]
Show full quote

Sorry, dude, but from what you describe you did this could be anything.
First you should never run a CPU with a double digit (or higher) TDP without a heatsink or at least some thermal mass to draw heat away from the silicon die. The Coppermine CPUs do have some thermal protection but with a little bad luck you can still fry your setup. Also heat degrades any CPU even if it doesn't kill it right away. A small cooler is better than no cooler for a test.
Second when taking apart a machine all sorts of problems may arise which will make troubleshooting (especially remote troubleshooting) very hard.
My first suggestion is to restore the last working configuration, in the process visually inspect the system, reseat all components and clear your CMOS, then try powering the machine up again.
Fingers crossed!

Thank you for the fast reply, I followed your advice and went back to square one.

I reassembled everything and bought some cheaper made but more readily available thermal paste and retried with the original configuration Celeron 600 Mhz CPU. It booted with no problems, so as soon as I saw the line on the screen I shut it off. Did the same with the 866mhz P III right after with thermal paste also, and it went back to no image, so I guess that the 866mhz is not recognised by my motherboard:

"Processor - Intel® Pentium® III & Celeron® (66/100/133Mhz Front Side Bus) (FCPGA Type).
- 300/333/350/366/400/433/450/466/500/533/550/600/650/667/700MHz or above."

As a beginner, what Pentium III processor would you recommend for me to look for this motherboard? Is a 500mhz Pentium III, for example, better than my 600mhz Celeron?

My front panel lights are still not turning on, I have doubts about the connections. I don't know if I can ask here or create a new thread but here it goes:

After inserting all the obvious pin cables on the board, I have two cables left with no written entry on the board:

- "Turbo LED" 2 pins cable, with no apparent input on the board, white and yellow wires;

- and the "Power LED" 3 pins cable, which entry is only of 2 pins on the board, white and green wires.

Other written board free pin entries:

- EXTSMI - 2 pins

- KEY LOCK - 5 pins

- INFRARED - 4 pins

How should I connect the remaining two cables?

Thank you so much for all your help.

The board should be able to drive the 866MHz chip. Either the chip is dead (which might have happened by your own hand) or the motherboard has issues. Have you tried updating the BIOS by any chance? Maybe there's an issue with detection of newer CPUs that prevents POST and got fixed in later BIOS.

Regarding the LEDs: Are you sure they're plugged in the right way around?
You can use the Turbo LED of your case to connect to the power LED header if both are 2-pin.
The upper three pins of the keylock connector are often used for Power LED as well. You can hook up your 3-pin Power LED cable there. The lower two pins are used for the actual keylock switch in this config if your case features that lock/switch.
LEDs may also have failed and need to be replaced if none of this works.

EXTSMI is used to hook up an SMI switch. You probably won't need it, especially since there's no switch on your case to hook it up to.

Infrared is for an infrared connection. Your case likely doesn't feature that, don't worry about it.

Hope this helps! 🙂👍

Doornkaat wrote on 2020-08-10, 22:23:

The board should be able to drive the 866MHz chip. Either the chip is dead (which might have happened by your own hand) or the m […]
Show full quote

The board should be able to drive the 866MHz chip. Either the chip is dead (which might have happened by your own hand) or the motherboard has issues. Have you tried updating the BIOS by any chance? Maybe there's an issue with detection of newer CPUs that prevents POST and got fixed in later BIOS.

Regarding the LEDs: Are you sure they're plugged in the right way around?
You can use the Turbo LED of your case to connect to the power LED header if both are 2-pin.
The upper three pins of the keylock connector are often used for Power LED as well. You can hook up your 3-pin Power LED cable there. The lower two pins are used for the actual keylock switch in this config if your case features that lock/switch.
LEDs may also have failed and need to be replaced if none of this works.

EXTSMI is used to hook up an SMI switch. You probably won't need it, especially since there's no switch on your case to hook it up to.

Infrared is for an infrared connection. Your case likely doesn't feature that, don't worry about it.

Hope this helps! 🙂👍

Thank you so much, regarding the LED's I took the initiative to try to figure it out ahead as per your explanation and it worked. Thank you so much for your help, I really couldn't have done it without it. They look different now, I think that the lights were incorrectly connected even way before I disassembled it for cleaning it this time, let alone after!

About your suggestion, I never updated a BIOS before, but I know that this board is somewhat obscure, I'm not even sure it is this very model because of the lack of references and I couldn't find any software for it... http://www.motherboard.cz/mb/sg/SG-APP133AB3.htm

As for the CPU I guess I'll wait for the heatsink and cooler to arrive before I find another one, maybe a 800mhz Pentium III, I really hope it gets recognised by the board. I'm kind of unsure now due to the limit, but I really want to believe you. All I wanted was to find the best possible Pentium III processor within the socket 370 line to replace this 600mhz Celeron. I thought it would be a simple switch but I guess my newbieness made it all unravel.

The thing that is really unpractical is that in any case I have to install all of it - heatsink, cooler, thermal paste - with any new CPU as if it was a definitive install, just to even check that it is working. Given the torture I apparently submitted these two CPUs - more our less 5 seconds each time without paste or cooler to check if it booted - I guess I shouldn't take the risk anymore.

Happy to help! 👍
Could you post some pictures of your board, ideally with the name visible on it?

The initial (and only) BIOS release is from August 2000 if the notes I found can be trusted. All Coppermine PIIIs were released by then so it would be strange not to support them but then again this is not a reputable brand as far as I can tell.

If there are any jumpers to set 100MHz FSB you could try underclocking the 866MHz CPU to 650MHz.

Doornkaat wrote on 2020-08-11, 03:25:

Happy to help! 👍 Could you post some pictures of your board, ideally with the name visible on it? […]
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Happy to help! 👍
Could you post some pictures of your board, ideally with the name visible on it?

The initial (and only) BIOS release is from August 2000 if the notes I found can be trusted. All Coppermine PIIIs were released by then so it would be strange not to support them but then again this is not a reputable brand as far as I can tell.

If there are any jumpers to set 100MHz FSB you could try underclocking the 866MHz CPU to 650MHz.

I'll try:

https://pasteboard.co/JlSvwu4.jpg
https://pasteboard.co/JlSvOE8.jpg
https://pasteboard.co/JlSw11t.jpg

I don't think I'll want to keep the 866mhz CPU, I'll always fear that I damaged it due to my testing.

This PC had an authentic zoo inside it when I bought it at a fair, and had a lot of humidity also. When I was disassembling it a few days ago one of the socket clips on the motherboard broke when I unlocked the heatsink/cooler from it. The plastic feels somewhat brittle, and the rest must have been my fault too.

So now I have two options:

I can end up finding a new CPU, a 700mhz Pentium III or higher one if you think it's possible, keep this motherboard, and glueing the heatsink/cooler to the CPU using thermal glue or double sided thermal tape;

Or for just a little more I'll buy a new motherboard/CPU combo and be done with it. I was trying to change just the CPU so I could keep all the W98SE configuration that I had for the past 3 years, but with all the tribulations I don't know anymore. Thankfully this hardware is still kind of cheap nowadays...

That's not how you apply thermal paste to a bare-core CPU (or any CPU for that matter). I hope it was non-conductive paste.

Oetker wrote on 2020-08-11, 14:24:

That's not how you apply thermal paste to a bare-core CPU (or any CPU for that matter). I hope it was non-conductive paste.

Hello, this was already after many mistakes on my part regarding the CPUs that I wrongfully tested. Right now I'm only counting on keeping the motherboard, if that even happens...

How did you clean the motherboard? It might have been damaged during cleaning, for example due to static discharge.
Does the power supply fan still turn on?
If one of the retaining clips for the heatsink broke off, you might still be able to use one that uses the outer (larger) plastic clips. However you might just be better off buying a new board and CPU, these are all pretty common parts, it would still be a shame if you've killed them but that's very difficult to tell without known good parts to test with.

Oetker wrote on 2020-08-11, 14:31:

How did you clean the motherboard? It might have been damaged during cleaning, for example due to static discharge.
Does the power supply fan still turn on?
If one of the retaining clips for the heatsink broke off, you might still be able to use one that uses the outer (larger) plastic clips. However you might just be better off buying a new board and CPU, these are all pretty common parts, it would still be a shame if you've killed them but that's very difficult to tell without known good parts to test with.

As a noobie I cleaned/reassembled the whole case, tested the new 866mhz CPU I got for about 5 seconds without paste or cooling to see if it would boot. Nothing appeared on the screen, so I thought that it was defective or that I fried it. Now I understand that the board might not even support it, it's kind of obscure and I'm not 100% sure what board model/brand it is.

Out of nervousness I quickly did the same with the old Celeron, and nothing. After reassembling everything again and applying the paste you see on the Celeron, it booted, so I shut it off immediately.

Now, with the broken bracket on the board, and two CPUs that I fear I might have degraded with my ignorant quick testing, I'm at a crossroads with this.

I will always have to apply thermal paste to a CPU like this in the future when the new heatsink and cooler arrive, could you please explain what is "bare core" and how do I apply the thermal paste when the time comes? Thank you so much.

andre_6 wrote on 2020-08-11, 14:39:

I will always have to apply thermal paste to a CPU like this in the future when the new heatsink and cooler arrive, could you please explain what is "bare core" and how do I apply the thermal paste when the time comes? Thank you so much.

CPU's such as the Coppermine Pentium 3 you're using have a bare core (the blob in the middle) as opposed to a plastic package or a metal heat spreader. In general, always apply paste like in this image I image searched:
See this image: https://i272.photobucket.com/albums/jj163/ido … edwithNT-H1.jpg

For a CPU such as yours you need to be extra careful, as you don't want to get thermal paste on the components other than the core itself. A bit of paste getting on the green circuit board isn't a big deal, but you don't want to get paste on any vias ( = wire through the cpu board) or resistors, etc.

Oetker wrote on 2020-08-11, 14:48:

CPU's such as the Coppermine Pentium 3 you're using have a bare core (the blob in the middle) as opposed to a plastic package or […]
Show full quote

andre_6 wrote on 2020-08-11, 14:39:

I will always have to apply thermal paste to a CPU like this in the future when the new heatsink and cooler arrive, could you please explain what is "bare core" and how do I apply the thermal paste when the time comes? Thank you so much.

CPU's such as the Coppermine Pentium 3 you're using have a bare core (the blob in the middle) as opposed to a plastic package or a metal heat spreader. In general, always apply paste like in this image I image searched:
See this image: https://i272.photobucket.com/albums/jj163/ido … edwithNT-H1.jpg

For a CPU such as yours you need to be extra careful, as you don't want to get thermal paste on the components other than the core itself. A bit of paste getting on the green circuit board isn't a big deal, but you don't want to get paste on any vias ( = wire through the cpu board) or resistors, etc.

Thank you very much for such a concise and clear explanation!

Looking at your picture, apparently your board has jumpers to select which multiplier to use. Your 600MHz Celeron should run at 66x9, however the jumper info on the board doesn't mention a x9 multiplier. Looking at JP7, it seems to be jumpered for x3. Which is strange because as far as I know there's no socket 370 chips that would use that multiplier. Anyway, if it's really at x9, that would explain why your 866MHz chip won't work, that needs to be jumpered for 133x6.

Edit: those jumpers probably only do anything for unlocked CPU, which you don't have. But you could still try setting it to x6.

Oetker wrote on 2020-08-11, 15:02:

Looking at your picture, apparently your board has jumpers to select which multiplier to use. Your 600MHz Celeron should run at 66x9, however the jumper info on the board doesn't mention a x9 multiplier. Looking at JP7, it seems to be jumpered for x3. Which is strange because as far as I know there's no socket 370 chips that would use that multiplier. Anyway, if it's really at x9, that would explain why your 866MHz chip won't work, that needs to be jumpered for 133x6.

Thank you, with the broken bracket and the fear of having degraded the 866mhz CPU that I bought with my reckless testing, I'm honestly leaning to just getting a new board+CPU combo. Probably shoudln't have got the heatsink and cooler on a rush at the time, but maybe it will be useful if the combo I end up buying is not mounted already.

Thanks for the pics. Sadly there's no explaination of the jumpers printed on the PCB apart from (useless) FSB jumpers.
I couldn't find a manual either and it seems like there's only the original BIOS for this board avaliable. I'm more and more convinced this motherboard actually has trouble supporting the faster contemporary CPUs.

It looks like there's enough of the retention hook left to carefully attach a smaller aluminium heatsink. Don't move the computer around too much after that. 😉 You can also try to superglue a small piece of plastic (not all plastics work well with superglue though) metal or wood to reinforce what's left of the hook.
My suggestion would be to put the celeron back in and mount the heatsink again. Maybe the board is a little janky and if it breaks for good there's not much lost.
Until then: USE IT! 😁 A 700MHz Celeron is good for a plenty of Win98 gaming and for a high performance setup you're probably better off with a better motherboard anyway. This isn't the machine to secure all the bragging rights in 2000 but it's a useful and reasonable contemporary setup.

Doornkaat wrote on 2020-08-11, 15:32:

Thanks for the pics. Sadly there's no explaination of the jumpers printed on the PCB apart from (useless) FSB jumpers. I couldn' […]
Show full quote

Thanks for the pics. Sadly there's no explaination of the jumpers printed on the PCB apart from (useless) FSB jumpers.
I couldn't find a manual either and it seems like there's only the original BIOS for this board avaliable. I'm more and more convinced this motherboard actually has trouble supporting the faster contemporary CPUs.

It looks like there's enough of the retention hook left to carefully attach a smaller aluminium heatsink. Don't move the computer around too much after that. 😉 You can also try to superglue a small piece of plastic (not all plastics work well with superglue though) metal or wood to reinforce what's left of the hook.
My suggestion would be to put the celeron back in and mount the heatsink again. Maybe the board is a little janky and if it breaks for good there's not much lost.
Until then: USE IT! 😁 A 700MHz Celeron is good for a plenty of Win98 gaming and for a high performance setup you're probably better off with a better motherboard anyway. This isn't the machine to secure all the bragging rights in 2000 but it's a useful and reasonable contemporary setup.

Thank you for looking that up, I didn't find anything at the time. That's exactly what I used this PC for, I'm leaning towards switching the board cpu combo and close this PC for good after that as my Pentium III W98SE gaming pc. I will keep the board and Celeron for another PC in the future. Thank you Doornkaat and Oetker for all your help, Vogons never fails in providing help to less knowledgeable guys like me!

There is a method to "grow" back the plastic. The procedure is to apply a thin layer of super glue on top of the plastic you wish to grow, then sprinkle baking powder on it. Remove the excess powder and let it dry, then repeat the process in the direction you want it to grow (somewhat like 3D printing). Eventually it will be big enough that you could trim it down by filing gently. The resulting "grown" plastic is very strong. Of course if you're doing this on the socket you'd want to first tape up the surrounding board & components for protection.

Regarding the poor CPU in the photo (it's the Celeron I guess?), you could still clean up all the thermal paste by first wiping with paper towels, follow by cleaning with alcohol.

I've also found an archive with Supergrace BIOS. The SG-APP133AB3 is listed. Not sure what CPUs the BIOS would support though, as there is no mention of it.

kalohimal wrote on 2020-08-11, 15:55:

There is a method to "grow" back the plastic. The procedure is to apply a thin layer of super glue on top of the plastic you wish to grow, then sprinkle baking powder on it. Remove the excess powder and let it dry, then repeat the process in the direction you want it to grow (somewhat like 3D printing). Eventually it will be big enough that you could trim it down by filing gently. The resulting "grown" plastic is very strong. Of course if you're doing this on the socket you'd want to first tape up the surrounding board & components for protection.

Regarding the poor CPU in the photo (it's the Celeron I guess?), you could still clean up all the thermal paste by first wiping with paper towels, follow by cleaning with alcohol.

I've also found an archive with Supergrace BIOS. The SG-APP133AB3 is listed. Not sure what CPUs the BIOS would support though, as there is no mention of it.

Would have never thought that was possible, thank you!

If you plan to do that, I suggest you practice first on some unwanted plastic, before doing it on the actual socket. And for your PIII 866, I think there is a good chance it might still be ok, since 5s is not too long, and the CPU has thermal protection. Just don't do that again with another CPU, and always attach a heat sink before power on, no matter how tedious it seems to be.