VOGONS


First post, by LewisRaz

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Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use.

It originally had a 166mhz mmx but I decided to fit a 200mhz instead. I cannot however get it to run at 200mhz!

The problem is that the board considers pins 1-2 closed all of the time, even if a jumper is not present. I have checked the board over physically and it is immaculate. No indication of any problem traces or solder joints that have bridged anything.

Has anyone seen anything similar before? Not a big deal just something that is leaving me somewhat confused.

Reply 1 of 18, by Horun

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Have only seen that happen when there was some BIOS corruption or bad traces.
Can you take a good picture of the board and post it ?
I uploaded the manual in case you do not have it. http://www.vogonsdrivers.com/getfile.php?fileid=1755

Hate posting a reply and have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. 🤣 Second computer a 286 12Mhz with real IDE drive ! After that came 386, 486, Pentium, P.Pro and everything after....

Reply 2 of 18, by LewisRaz

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Thankyou for the manual. I will attempt to get some high quality pictures of the board later today. I have noticed there is still a BIOS hosted on gigabyte website so may give that a try.

I have tested with a multimeter and the pins do not appear to be bridged!

Reply 3 of 18, by Doornkaat

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Hi! Some BIOS are so old they don't support proper frequency detection for all possible CPU speeds.
I'd recommend using system diagnostics software to determine the actual CPU speed first if you haven't done so already.

I have no idea of your insight on that matter, so I'm giving a rather lengthy explaination. Please don't think I'm trying to be condescending if you already knew all/most of this. 😀
If the actual CPU speed as measured by software turns out to be 166MHz instead of 200MHz though, the problem is probably not the board ignoring the jumper settings but most likely an electrical fault.

While the board is responsible for the FSB frequency (JP8 & JP9 on your board) the multiplier is configured through jumpers on the board but recognised/interpreted only by the CPU.
The multiplier jumpers on the board (JP11, pins 1+2/3+4 on your board, pins 1+2 handling BF0, pins 3+4 handling BF1) effectively bridge the BF pins on the CPU to logical ground. This is handled completely analog, not in software. There is no way the board can interpret anything wrong. The board has no 'knowledge' of the CPU internal multiplier. (Except for very few boards that actually use some logic for this. The BIOS on any board can erreneously interpret the actual CPU frequency though.)
There are two BF pins on a Pentium MMX: BF0 and BF1. Normally they're logical high/1, shorting them to ground sets them to logical low/0.
Since shorting them to ground is done by setting a jumper on the board, the set jumper represents logical low/0 while not having a jumper set is logical high/1.
The multiplier settings for the 200MMX are: BF0: 1 / BF1: 0. The multiplier settings for the 166MMX are: BF0: 0 / BF1: 0.
This means (if your CPU frequency is not just erreneously detected as 166 instead of 200 by the BIOS) you most likely have an electrical problem on your board that results in BF0 being connected to ground regardless of jumper setting of JP11, pins 3+4.
You can check this by probing with a multimeter wether JP11 pin 3 and 4 are both connected to ground with no jumper set and no CPU inserted.
-If so there's a short somewhere on the board.
-If not you probably have a faulty CPU.

I hope this helps. 👍

PS: All jumper descriptions based on the CPU speed configuration table found within the manual on http://www.win3x.org/uh19/motherboard/show/2731.

Reply 4 of 18, by LewisRaz

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Many thanks for that write up!

I can confirm that the board is running at the displayed 166mhz. I have tried 2 different CPU so that would point towards BF0 being grounded somewhere!

Gives me something to take a look at! I did consider cutting that trace although thats quite dramatic and not guaranteed to work if the short is before that point.

Reply 5 of 18, by Riikcakirds

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LewisRaz wrote on 2020-12-16, 18:23:
Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use. […]
Show full quote

Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use.

It originally had a 166mhz mmx but I decided to fit a 200mhz instead. I cannot however get it to run at 200mhz!

The problem is that the board considers pins 1-2 closed all of the time, even if a jumper is not present. I have checked the board over physically and it is immaculate. No indication of any problem traces or solder joints that have bridged anything.

Has anyone seen anything similar before? Not a big deal just something that is leaving me somewhat confused.

I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket.
Are you sure the 166mhz cpu you have is an mmx version.
I;ve been wary to try an mmx cpu in case I damaged the board.

Reply 6 of 18, by LewisRaz

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Riikcakirds wrote on 2020-12-17, 16:54:
I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket. Are […]
Show full quote
LewisRaz wrote on 2020-12-16, 18:23:
Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use. […]
Show full quote

Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use.

It originally had a 166mhz mmx but I decided to fit a 200mhz instead. I cannot however get it to run at 200mhz!

The problem is that the board considers pins 1-2 closed all of the time, even if a jumper is not present. I have checked the board over physically and it is immaculate. No indication of any problem traces or solder joints that have bridged anything.

Has anyone seen anything similar before? Not a big deal just something that is leaving me somewhat confused.

I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket.
Are you sure the 166mhz cpu you have is an mmx version.
I;ve been wary to try an mmx cpu in case I damaged the board.

My one definitely supports them! (Just took this pic.)

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Reply 7 of 18, by Riikcakirds

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LewisRaz wrote on 2020-12-17, 17:09:
Riikcakirds wrote on 2020-12-17, 16:54:
I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket. Are […]
Show full quote
LewisRaz wrote on 2020-12-16, 18:23:
Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use. […]
Show full quote

Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use.

It originally had a 166mhz mmx but I decided to fit a 200mhz instead. I cannot however get it to run at 200mhz!

The problem is that the board considers pins 1-2 closed all of the time, even if a jumper is not present. I have checked the board over physically and it is immaculate. No indication of any problem traces or solder joints that have bridged anything.

Has anyone seen anything similar before? Not a big deal just something that is leaving me somewhat confused.

I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket.
Are you sure the 166mhz cpu you have is an mmx version.
I;ve been wary to try an mmx cpu in case I damaged the board.

My one definitely supports them! (Just took this pic.)

Great, do you know if it's running at the higher 3.3v or 2.8v.

Reply 8 of 18, by Doornkaat

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LewisRaz wrote on 2020-12-17, 15:32:

Many thanks for that write up!

I can confirm that the board is running at the displayed 166mhz. I have tried 2 different CPU so that would point towards BF0 being grounded somewhere!

Gives me something to take a look at! I did consider cutting that trace although thats quite dramatic and not guaranteed to work if the short is before that point.

Always happy to help!👍
You can also try insulating the pin on the CPU i.e. with lacquer or - if you're feeling brave - completely removing it. It is not needed for 3x and 1.5x/3.5x multi anyway. If you cut something I'd recommend you cut the pin though. The CPU is easier to replace than the motherboard.😉

Reply 9 of 18, by LewisRaz

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Doornkaat wrote on 2020-12-17, 18:46:
LewisRaz wrote on 2020-12-17, 15:32:

Many thanks for that write up!

I can confirm that the board is running at the displayed 166mhz. I have tried 2 different CPU so that would point towards BF0 being grounded somewhere!

Gives me something to take a look at! I did consider cutting that trace although thats quite dramatic and not guaranteed to work if the short is before that point.

Always happy to help!👍
You can also try insulating the pin on the CPU i.e. with lacquer or - if you're feeling brave - completely removing it. It is not needed for 3x and 1.5x/3.5x multi anyway. If you cut something I'd recommend you cut the pin though. The CPU is easier to replace than the motherboard.😉

After understanding your first post as I did I did wonder if cutting the pin would work.

The cpu was a 99p ebay win iirc and I also have the original 166mmx so it would not be the end of the world if the attempt failed!

Is the pin relatively easy to locate? I will have a look on google soon but asking someone who knows is always nice 😀

Thanks

Reply 12 of 18, by LewisRaz

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Riikcakirds wrote on 2020-12-17, 16:54:
I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket. Are […]
Show full quote
LewisRaz wrote on 2020-12-16, 18:23:
Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use. […]
Show full quote

Hello all. I have a socket 7 motherboard GA-586ATS that I use as my "Main" retro machine, getting almost daily use.

It originally had a 166mhz mmx but I decided to fit a 200mhz instead. I cannot however get it to run at 200mhz!

The problem is that the board considers pins 1-2 closed all of the time, even if a jumper is not present. I have checked the board over physically and it is immaculate. No indication of any problem traces or solder joints that have bridged anything.

Has anyone seen anything similar before? Not a big deal just something that is leaving me somewhat confused.

I have this board, didn't think it supported Pentium MMX cpus's as it's an older 430fx chipset and has no vrm module socket.
Are you sure the 166mhz cpu you have is an mmx version.
I;ve been wary to try an mmx cpu in case I damaged the board.

Hi there it is definitely an MMX. Here are the power settings on motherboard

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Reply 13 of 18, by Doornkaat

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LewisRaz wrote on 2020-12-17, 21:02:

Yes please! Not having much luck on google.

Disclaimer: I think this goes without saying but you're performing all modifications on your own risk and even though I triple checked my picture I do not take responsibility if I made any mistakes.
Ok, with that out of the way 😉 :
You need to remove BF0 for the corresponding signal to always be high regardless of motherboard jumper settings. BF0 is pin Y33 on the socket.
Online you find pinouts looking at socket from above as well as looking at the CPU from the bottom.
In order to avoid confusion over pinouts looking at the socket from above or from the backside of the board or directly at the CPU pins I marked the BF pins on a picture of an actual CPU.
The green dot and arrow mark BF0, BF1 is the blue dot, BF2 is the red dot.
BF2 is not used on Pentium MMX CPUs but K6-2 and up should use them iirc.
The three pins marked white with a black dot are the nearest Vss pins. Bridging any of the BF pins to one of the Vss pins will permanently pull this BF pin's signal low. (Like setting a jumper on the board would.) This way you can select multipliers supported by your CPU on boards that don't offer the necessary jumpers.
All of this is assuming your CPU is functioning correctly and doesn't have any locked multipliers.

Good luck! 😁

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Reply 15 of 18, by LewisRaz

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Doornkaat wrote on 2020-12-18, 12:40:
Disclaimer: I think this goes without saying but you're performing all modifications on your own risk and even though I triple c […]
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LewisRaz wrote on 2020-12-17, 21:02:

Yes please! Not having much luck on google.

Disclaimer: I think this goes without saying but you're performing all modifications on your own risk and even though I triple checked my picture I do not take responsibility if I made any mistakes.
Ok, with that out of the way 😉 :
You need to remove BF0 for the corresponding signal to always be high regardless of motherboard jumper settings. BF0 is pin Y33 on the socket.
Online you find pinouts looking at socket from above as well as looking at the CPU from the bottom.
In order to avoid confusion over pinouts looking at the socket from above or from the backside of the board or directly at the CPU pins I marked the BF pins on a picture of an actual CPU.
The green dot and arrow mark BF0, BF1 is the blue dot, BF2 is the red dot.
BF2 is not used on Pentium MMX CPUs but K6-2 and up should use them iirc.
The three pins marked white with a black dot are the nearest Vss pins. Bridging any of the BF pins to one of the Vss pins will permanently pull this BF pin's signal low. (Like setting a jumper on the board would.) This way you can select multipliers supported by your CPU on boards that don't offer the necessary jumpers.
All of this is assuming your CPU is functioning correctly and doesn't have any locked multipliers.

Good luck! 😁

Many thanks for your write up!

I will attempt removal of the green pin on your diagram and reply with the results! 😀

I also updated the bios last night with the one from gigabytes website dated 1‎998/05/05. The one I had was 1995. It now shows pentium MMX instead of pentium-s which is nice.

Thanks

Reply 17 of 18, by Doornkaat

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Very weird. Again, this is the actual frequency as measured by software?
Could you post a full pic of your board?
Also have you tried overclocking the MMX 166 yet? Maybe your 200MHz CPU is damaged and for some reason BF0 is pulled low internally...
Edit: Nvm the oc question. You already said you tried it.
Edit2: Maybe your 166MHz chip is multiplier locked?