CPU exchanged and nothing works...

[pemao]

I have a P-Bell C 115 with a pentium 120 MHz. Now I wanted to exchange it with a fast IBM 6x86 CYRIX. After I exchanged the two CPU's and I reboot my computer nothing happens. Is there a reason why the new CPU is not working?

[MR COMPUTER]

Probably a lot of reasons.Does your mainboard support the Cyrix chip? Voltage,bus speed,cpu type,and clock speed jumpers have to be changed. Does your PB need a bios upgrade for this to work? http://www.sysopt.com/forum/wink.gif

[pemao]

Thanks for the quick reply. Now I have to find a way to find out how to get all this information. My PB did not come with a manual. So I went to there web page and down loaded at the BIOS upgrade because I that that this was the problem. It wasn't.

[800XL]

Many many Packard Bell machines of that age use an Intel motherboard with an AMI bios. That bios will not go with any CPU that is not an Intel, or in quite a few cases the IDT Winchip. Cyrix CPUs will not work without a bios upgrade from someone other than Intel or Packard Bell. The most common bios upgrade that will work in this case would be an MRBios www.mrbios.com (http://www.mrbios.com) . The other issue that could be going on here is one of voltage. There were some straight voltage (same as your Pentium 120Mhz) but the lion's share of them were dual voltage. That means the core of the CPU needs to have 2.8volts while the I/O gets 3.3volts. A straight voltage chip gets 3.3v to both. You could be up against one or both of these problems. Likely you are looking at a bios issue, but even if you resolve it you may have to face the voltage problem. Odds are your motherboard cannot be set to split/dual voltage. Check the top of your Cyrix chip and look for something like 2.8v. That will be a dead giveaway.

You would probably be better served by attempting to overclock your current 120Mhz to at least 133Mhz. That is a very mild overclock, and should work without too much trouble at all. Higher may be possible, but the motherboard could again limit you. Look through your manual for how to set the machine for a 133Mhz CPU, and follow those instructions. If you can provide me with some more info about the motherboard I can probably conjure up the settings you need if your manual does not help. Get it booting again, and look at the info that comes up right when you start the machine. If you see the word Agoura, that is enough to tell me what board you have. Otherwise look for a set of numbers and letters that look like 1.00.08.BY0R or something like that.

[pemao]

Thanks again for all your inside. I guess I have to start thinking about sending my Packard Bell to the Museum of modern art. Old and outdated. The problem is that even though I bought this PC at a regular store it did not come with any manual. When I reboot it it Said : American Megatrents, Inc./Intel 1.00.12 DNOR. CPU 120 Intel Type P54C Auto HTL. I even downloaded an BIOS upgrade provided by Packard Bell on there web page. So how do I overclock? Don't I have to worry then about the heat? I would be thankful for any idea.

[800XL]

[rul]http://www.measham.force9.co.uk/pb/mb/680.htm[/url]

Take a look at this web page. It has jumper settings for your motherboard, as near as I can tell. All you have to do to overclock is change the jumpers to match the setting for a higher speed. I've had very good luck overclocking P120 chips in the past, but you may not want to jump to far past 133, at least at first. 120 to 133 is a very minor change in speed/heat output compared to the gains. I doubt heat will be anything of a problem for that much of a jump. Higher than that may require some extra cooling, depending on what sort of heatsink/fan combo you have now.

[DavidX]

www.measham.force9.co.uk/pb/mb/680.htm (http://www.measham.force9.co.uk/pb/mb/680.htm)

[pemao]

Thanks again for your help. I have successfully been able overclocking my 120 chips to 133 MHz. Now if I wanted to go higher a fan would be needed right? What kind of fan would be the best?

I can now see that my motherboard runs with 3.3V. That's why my Cyrix CPU was not working which runs with 2.8 V.

Thanks 800XL and DavidX

[800XL]

Thanks for fixing my url typo David. 30+ hours with no sleep starts to do strange things to ya.

That motherboard you have will not run anything that I know of besides an original Pentium classic and a Winchip. The Winchip may be an option, but likely you will have problems with the multiplier. As for overclocking your 120Mhz, you can go for higher than 133Mhz with most heatsink fan combos, but watch the heat. If the chip or heatsink is getting to where it borders on 'ouch' hot, then you are probably going to far. I have been able to overclock 133Mhz pentiums to 200Mhz on many occasions, but you can't really tell unless you try. Move up a step at a time, and see how things perform. Check the chip for serious overheating, and if you hit any instability back it down a notch. I can tell you that going from 133Mhz up to 150Mhz is a waste. The drop in bus speed outweighs the gain in Mhz and you will not see much difference. As long as your heatsink and fan seem to be performing ok at 133, go straight for 166 and see how it does. As always, it is unlikely to permanently damage things, but there is no doubt some risk. Be careful and if you see any weirdness, back off some. In my experience, briefly going above what a chip can handle will only cause it to run flaky at that setting. Backing down to previous known good settings brings thing back to correct functioning.

[pemao]

I have not been able to get my CPU to run faster than 133 not even to 150. I guess the
PB does not like any faster speed. I also tried to upgrade my modem and sound card but
it failed as well. PB support told me that I need to use there dual modem. (Modem &
Sound card on one card)

[DavidX]

Try this site:
www.geocities.com/SiliconValley/Lakes/8774/pb640.html (http://www.geocities.com/SiliconValley/Lakes/8774/pb640.html)
All you ever wanted to know about upgrading Packard Bells (including the PB680 mobo). You'd be amazed what some people have managed to get a humble PB640/680 to do. One which started off running with a standard Pentium 133MHz is now running with an AMD K6-III at 400MHz (thanks to PowerLeap adapter and BIOS upgrade)! It may not be really worth it because of other bottlenecks and limitations with a mobo that old (I personally feel that if you need to start looking at solutions like PowerLeap, then it's time to just get a new motherboard or computer) - but it is impressive. Read the Upgrade Stories section and see the success stories of sound, modem, video and other upgrades. There's lots of information that Packard Bell never tells you.

Also, don't forget to click on the "Ray's Packard Bell Web Site" link next to the Copyright at the bottom of that page for yet more links.

[This message has been edited by DavidX (edited 07-03-99).]

[800XL]

I sorta left out the powerleap/evergreen upgrade style of upgrading that board. That will get you up there in the K6-2/3 range, but 400 is tops. 6x is max for a K6-X and 6x66=400. You WILL need a bios upgrade no matter which of these you go for. The Evergreen packages one with the upgrade if you are looking at going that far with this thing.

[DavidX]

edit~

[This message has been edited by DavidX (edited 07-03-99).]

[MrT]

I have the exact same machine. Well I could say it used to be. I did away with the 120 and installed a 200 mmx. Put in a new 4 meg video card,Sound Blaster 64,56k modem, 3.2 gig hard drive, and maxed the ram.
system runs good for what it used to be.
Just courious on why you didn't go with an intel chip?

[shulland]

I'm posting in this area because it looks like you all helped the PB guy in a timely manner with some great advice. I have a question and was wondering if any of you could help? I have a ASUS P2L97 motherboard with a 233 PII (non cleron) and thought I'd add a PII 400. Problem is the MB only goes to 83 MHz (66,75, and 83) on the bus freq. The freq mult. settings are 2, 3.5, 4.0, 4.5, and 5. Can I drop the 400 in and set the bus freq to say 83 and the mult to 4.5,or can I go say 83 and 5? The other option is overclocking the 233? Have you all seen another place I could post this message for help? Thanks Hoakey

[pemao]

Thanks again for all the great ideas. I send an e-mail to PB support and I was told to go
with Pentium w/ a 680. So I guess I will get me a Intel 200 MMX.
Why I went with a Cyrex? Well, my brother had it as a left over. He is using now in his
self build machine a K6 III running on 600 MHz.
I think I have to build me my next computer.