VOGONS


First post, by 90skidJohnny

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Ive finally got my PB450 Motherboard (Packard bell Legend 10CD) to accept a 3.3v CPU by adding some capacitors and a voltage regulator. (Board has jumper settings for 3.3v but until you add the missing parts, will only accept 5v)

Anywho, finally power this guy on and.... black screen. No beeps. So i thought i may have put a cap in backwards (a mistake ive made before. Dont judge. These SMD's are tiny)
With the computer still running I was using my multimeter to check voltages and BEEP! Packard Bell Bios and all that good stuff pops on screen. Originally I thought I must have shorted something with one of the meters probes causing it to boot, but no.. It just takes forever for it to show the boot screen.

Forever being 17 seconds to be exact. While not extremely long, i dont remember it ever taking that long for a computer to Post. Im in the process of restoring this pc (Bought as is Ebay) with no cpu (hence the 3.3v mod) Currently All I have is memory connected to the board, and no matter how little or how much i put in, still takes 17 seconds to Post.

Also, i know the system battery is dead, i havent replaced yet, but could that be causing the long post times?

Any ideas or thoughts. lemme know. I dont mind the wait, but if its being caused by a bigger issue, id like to fix it.

Reply 2 of 12, by 90skidJohnny

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Warlord wrote on 2020-07-31, 02:58:

system battery could be the culprit. lucky for u its posts with a dead one. most boards dont even post.

Yah I was kinda wondering if it would post. Im actually waiting on a new coin cell holder to come in before i change it out.

Im hoping that is it. Im not the Greatest at soldering SMD stuff. I really need a nice microscope 🤣 So was just wondering if it was something ive done, but really, i dont see how. It was essentially just adding 2 unpopulated capacitors and a Voltage reg that also was unpopulated.

now im just thinking about running some wires real quick to a new battery to see if its any different.

Thank you for your input tho!

Reply 4 of 12, by Anonymous Coward

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I have the same problem on one of my EISA 486 boards. I've never been able to find out what causes it. It's not the battery (I swapped it).

"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 5 of 12, by amadeus777999

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That's a bit odd - 3 to 5 seconds is normally the maximum interval I came across.
The system battery being empty did not alter the boot up time on the old boards I tested(very few power on at all with an empty one).

Reply 7 of 12, by 90skidJohnny

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jakethompson1 wrote on 2020-07-31, 03:47:

Any way you managed to turn off turbo?

I dont believe so. This system doesnt really have like a turbo button, so it doesnt really have specifically a turbo header. It does have jumpers for CPU speed / multipliers tho. I "believe" i have that set correctly. Will double check.

One thing I noticed is im using a AMDX486-120 CPU. Technically it doesn't list this as a supported CPU in some manual i found online (Does have the 100Mhz version supported) so i have the mobo jumpers set to that.

One thing i do notice, is when the bios does display CPU, it says "386/486 100mhz" So .. its going down to 100mhz i assume due to the jumpers. I wonder if somehow that is causing the issue with the slow post

Reply 8 of 12, by waterbeesje

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This may cause the delay... The motherboard may be re-checking over and over which CPU is used, but fail to identify it.

Mentioning 100MHz down not mean the CPU is running at this speed. The bios simply may not be programmed to correctly report the speed. No Intel dx4 was intended to run at more than 100MHz as far as I know, so that may be what is reported.
For example, my Aptiva 2137 supports the K6-2 CPU, but when jumpered to 400MHz (66x6) it reports only 300MHz. A simple check with some benchmark software reports 400MHz as expected.

Have you checked what the board does with a SX/DX/DX2? Will it boot faster?

Stuck at 10MHz...

Reply 9 of 12, by jakethompson1

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waterbeesje wrote on 2020-07-31, 17:57:
This may cause the delay... The motherboard may be re-checking over and over which CPU is used, but fail to identify it. […]
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This may cause the delay... The motherboard may be re-checking over and over which CPU is used, but fail to identify it.

Mentioning 100MHz down not mean the CPU is running at this speed. The bios simply may not be programmed to correctly report the speed. No Intel dx4 was intended to run at more than 100MHz as far as I know, so that may be what is reported.
For example, my Aptiva 2137 supports the K6-2 CPU, but when jumpered to 400MHz (66x6) it reports only 300MHz. A simple check with some benchmark software reports 400MHz as expected.

Have you checked what the board does with a SX/DX/DX2? Will it boot faster?

That's a good point.

OP do you know if your Am486DX4 is "Standard" or "Enhanced"?
Take a look at the flowchart on page 10 of this https://en.wikichip.org/w/images/e/e1/AMD_BIO … %2C_1995%29.pdf
That's only for AMD, you can imagine there's a bigger flowchart inside your BIOS.
If your CPU doesn't support the CPUID instruction, then basically the BIOS has to benchmark it to figure out what kind of CPU it is.

Reply 10 of 12, by 90skidJohnny

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waterbeesje wrote on 2020-07-31, 17:57:
This may cause the delay... The motherboard may be re-checking over and over which CPU is used, but fail to identify it. […]
Show full quote

This may cause the delay... The motherboard may be re-checking over and over which CPU is used, but fail to identify it.

Mentioning 100MHz down not mean the CPU is running at this speed. The bios simply may not be programmed to correctly report the speed. No Intel dx4 was intended to run at more than 100MHz as far as I know, so that may be what is reported.
For example, my Aptiva 2137 supports the K6-2 CPU, but when jumpered to 400MHz (66x6) it reports only 300MHz. A simple check with some benchmark software reports 400MHz as expected.

Have you checked what the board does with a SX/DX/DX2? Will it boot faster?

Gotcha. That would make sense. Unfortunately this is the only CPU i have on hand at the moment , so cant really test what other processors support.
I am still trying to rig up a CPU fan (No cpu fan header on the board, so buiding something to attach to one of the Power connectors to feed 12v, so I have not ran it long enough to install an OS, etc, to run benchmarks.

That being said, you don't think this would cause any harm to the cpu tho right?

Reply 11 of 12, by 90skidJohnny

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That's a good point. […]
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That's a good point.

OP do you know if your Am486DX4 is "Standard" or "Enhanced"?
Take a look at the flowchart on page 10 of this https://en.wikichip.org/w/images/e/e1/AMD_BIO … %2C_1995%29.pdf
That's only for AMD, you can imagine there's a bigger flowchart inside your BIOS.
If your CPU doesn't support the CPUID instruction, then basically the BIOS has to benchmark it to figure out what kind of CPU it is.

Nothing on the cpu itself states in enhanced or plus. I actually removed all the gunked up thermal paste and heatsink to apply new so I actually have it out now.

Just basically says

AM486DX4-120
120SV88
C 9537APE

But the chart makes sense of why it could be a longer boot with all that for sure!

Reply 12 of 12, by 90skidJohnny

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That's a good point. […]
Show full quote

That's a good point.

OP do you know if your Am486DX4 is "Standard" or "Enhanced"?
Take a look at the flowchart on page 10 of this https://en.wikichip.org/w/images/e/e1/AMD_BIO … %2C_1995%29.pdf
That's only for AMD, you can imagine there's a bigger flowchart inside your BIOS.
If your CPU doesn't support the CPUID instruction, then basically the BIOS has to benchmark it to figure out what kind of CPU it is.

actually is Sv8B, which, according to some research, may make it the advanced version?