Hi all,

PC100 mobo with onboard sound and graphics (not sure of exact model)
Cyrix 333Mhz CPU
64mb SDRAM
MSP3880 modem
USB card

Hope someone can help with this. Just replaced the RAM in the above machine which was faulty, had the machine running fine with some other RAM which I had borrowed from another PC. Left it for a couple of days while I bought some more RAM for it, replaced RAM and switched it on and found the following;

Power light comes on
CPU fan runs (it's plugged into power supply rather than mobo)
CD light comes on
Nothing displayed on the monitor
No beeps
No FDD light

I've tried with some known good RAM and with no RAM with the same result,
it makes a few of the usual boot up noises (but not all) and then just sits there. I've not unpluged anything at all apart from the RAM. Where do I start? Any help appreciated!


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Cody Morgan

Whenever you are inside a machine and then have a no-boot situation afteryou reassemble it, the first thing to check and double check is that you haven't accidentally knocked anything loose.

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mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

Checked and double checked. Also I've tried another power supply to the mobo and got the same result, is there much else to try before concluding the mobo's dead? Is there anything else that could produce these symptoms?

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Cody Morgan

A defective CPU can cause the same symptoms.

G'day Cody,
How's things?

Is it possible that the memory is too slow for the system?

This might be another cause, for the symptoms you've described.

I'm not really sure, I hope it helps though.

Cheers,

Dazzler.

Pull the CMOS batt and leave it out for about half-n-hour, then reinstall batt and power up-may simply be a memory configuration error. This will clear the BIOS setings, placig them back to default, and allow it to verify/redetect the memory.



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iisbob

Computer-Show me the Enterprise; no bloody A, no bloody B, and no bloody C-just the original...Mr Scott { from a STNG episode }

Thanks for all the suggestions! I'll try taking the battery out as soon as I finish this and I do have another CPU that I can try. As regards the RAM, I could only buy PC133. I tested it with a piece of PC100 which was fine and then got the PC133, it was the first time I tried booting up with that in it that this happened - would that be coincidental? I have tried it with PC100 since but no joy, I didn't think that the RAM speed would cause a problem tho.

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Cody Morgan

Update .... tried leaving battery out for a while with no luck. Found that a friend has a machine with the same CPU in so switched them and found that the CPU is fine so I guess I conclude that the mobo is dead.
For future reference, does anyone have an opinion about whether trying to run it with PC133 RAM could have caused the mobo to fail? Could the mobo having problems have damaged the original RAM (which is definately faulty) or vice versa?

Thanks for the help!

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Cody Morgan

this may sound stupid but make sure that ur mobo is compatible with pc133, if ur previous pc100 ram works fine then that might be the problem.

if u want to check then look in your mobo manual and it shouled tell u

1. PC 133 is backward compatible, it should work fine on a PC 100 machine. That's exactly what one of the memory chips in my machine is...PC 133 in a PC 100 machine.

2. Did you make sure and turn off the machine completely or unplug it while changing RAM? If not you could have easily fried the motherboard, it still has power going to it when the main power switch (on back) is on, or when still plugged in if it has no main switch.

3. Did you also make sure to ground yourself while swapping parts? ESD or Electrostatic Discharge can fry components easily. It's more commonly known as static electricity. It takes 2000 volts for you to feel it, such as when you touch a door knob after walking across carpet, while it takes less than 100 volts to damage computer components.

Balrog: If you wish to answer questions, please do not use "net shorthand". Type the entire word, "u" is not a word, nor is "ur". We try for profesionality here, and often you will be dealing with people who have a limited understanding of English. Try to make it as clear and concise as possible.

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If your nose runs and your feet smell...
You're built upside down!
Note: Please post your questions on the forums, not in my email.

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Yes, the machine was unplugged when I replaced RAM and I had touched a central heating radiator in an attempt to discharge myself of any static.
I've never been too confident about what I need to do about discharging static. I know that the radiator or any other bare metal, earthed object, will discharge a build up of static but for how long and how long do I need to touch it for, does the static entirely discharge intananeously or should I give it a minute, how quickly can it build up again? Is an anti-static wrist band just a way of having a permanent connection to an earthed object or does it do something more? I've seen professionals connect these to the case of the machine they are working on but if it is unplugged from the mains at the time wouldn't that mean that it wasn't earthed and therefore not really doing anything?

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Cody Morgan

[This message has been edited by CM (edited 04-25-2002).]

Sneak up behind your kid brother and *almost* touch his
ear. That'll get rid of static electricity and your
brother for awile!

http://www.PCGuide.com/ubb/biggrin.gif

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....How long is a minute... depends on which side of the Bathroom door you're on. ......
..........

CM,
I've never seen a wrist band yet but can still somewhat clarify your static electricity question. I assume it's a band with a lead that clips to the frame for a grounded connection. VERY home-make-able. Unless I start working on valuable data, I will just continue the habit of touching the case often especially when I just walked up to it.

When the computer is sitting there unplugged, it is 'static' as in it can retain a charge other than it's surroundings unless it is connected to something that conducts electricity that is also connected to what will come in contact with it. The best way for you to neutralize yourself is to touch something conducting to 'earth' whether via a radiator (heating system) or plumbing which even the electric companies connect to near the service entrance. BTW it's nearly an instantaneous discharge therefore no need to sit and wait for the full effect. But this does not guarrantee you are of the same static charge as the PC you want to work on and you should make sure you touch the case for a second even if you rub your feet while sitting above carpet.

Hope this helps. I know it doesn't fit in a peanut shell but that's it in a nutshell nonetheless.

FTT

Hello CM

This problem seems to be very common. I've sent this info to quite a number of people now.
I will Email you info on the Boot sequence.

I'm using diagnostic flow charts.

1. The PC is not dead because you have lights etc.
2. It appears POST did not run and there were no audible beeps. This is, therefore, a POST problem.
3. I will assume that the power supply voltages are correct.[test if possible and if incorrect and the power input to the unit is ok (cable ok)then the PSU is faulty]
4. Disconnect all peripherals and system adapter cards except the keyboard and monitor.[After switching off and disconnecting from the power source naturally]
5. Boot the PC and if POST still does not run you have a faulty system board [This is only if your power supply is good](So says the chart but I wonder about the video card).
6. If it does run; re-connect the floppy and run advanced diagnostics if you can and test the system board. If the system board fails the tests then it is faulty. If it passes the tests then:
7. Switch off, re-connect one peripheral or adapter card and reboot. If post does not run then this last item is faulty. If it does boot test this last item with the diagnostics software. If it fails the test it is faulty.
8. Repeat step 7 until all items are reconnected and tested then re-test the whole system.
If it still does not function send me an Email.

I feel like the novice, but what is POST?
I have a similar problem after upgrading to PC133 memory and had to reset every time I booted up, although today it seems to have taken care of itself and booted up normally. Can it take a few tries for the system to recognize the memory properly?