View Full Version : Replaced power supply, still no power?
02-18-2001, 06:18 PM
I have an AMD K6 300 that powered up, then shut down and would not power up again, although the LED lights on the front would flicker. The power supply went out once before, so I installed a new power supply. The same problem continues. The heat sink fan moves slightly, the LED lights flicker, and that's all that happens. I'm a novice, but I want to learn how to repair my system and I'd appreciate any suggestions on what to do next, thanks.
02-21-2001, 02:39 AM
If you're having power issues, and you know it's not the power supply, that means the motherboard.
Make sure that it's not getting shorted out. I had a similar problem once and it ended up being one of the screws being too large and grounding out the board.
If that isn't it, then it's time to look at buying a new Motherboard :/
02-21-2001, 05:27 AM
are you using quality components??? you don't have to use top of the line equipment but, reliablity does require some cash.
Seek advice from patience, for ones who wait gets all the booty!
- Damn Right
02-21-2001, 04:46 PM
You didn't by chance try to reflash the bios or something like that did you? Does your motherboard (mobo) use a jumper to set the bios back to it's base or safe values? If you moved it and forgot to put it back to the operating position you will achieve the exact effect you are describing. Also if you didn't move that, try moving the jumper to the 2 pins not being use, hit the power (it won't look like it did anything), then move it back to it's base position. By doing that you are resetting the bios to it's base just in case it got messed up somehow.
Also you could have a silly thing like a floppy drive cable on backwards (pin 40-1, instead of 1-40), but unless you pulled the cable off it is probably in the correct position. It could also be the hard drive jumpered the wrong way (more than 1 master, etc.) the list is longer, but that is a good place to start.
Bad news is if you processor is fried, it will also do that, and probably the motherboard will get the same effect--that being when you hit the power the power supply fan twitches, but the computer does not boot.
Keep us updated--you can write me at home [email protected]
or at work [email protected]
02-21-2001, 07:32 PM
I know this sounds crazy, but check that the power supply is set to the correct voltage... there should be a red lever near where the power cord is. I hate to admit it, but those symptoms sound familiar to me....
I'm assuming your in the US, so it should be set to 110.
02-21-2001, 07:57 PM
I just thought I should mention never to experiment with the voltage swich on the power suply when the pc is powered up.... don't ask me how i know this:-)
02-21-2001, 09:35 PM
I really appreciate all the suggestions, I'm not sure what flashing the bios is so I don't think I did that. What I have done so far is remove the modem card and the sound card, same problem. Removed the video card, same problem. Removed the memory, same problem. I did remove the cables, but I marked them before I moved them so I'm pretty sure they are are all back in their correct places. I have the documentation on the motherboard and it looks like everything is where it is supposed to be. The voltage is set to 110. From the replies here and from what I have been reading in books it seems likely it is either the motherboard or the processor. I don't have another motherboard to test the processor with... what would you suggest I replace first? I'm not really interested in upgrading because I have another computer, I'm planning on donating this on to the place where I work once it is up and running. The processor is marked AMD K6 300AFR, the motherboard is an Epox 82430TX PCIset P55-TX 2. Thanks again for all the help, I do appreciate it!
02-22-2001, 02:43 AM
I take it your computer doesn't post? Meaning when you turn it on, you get a black and white text prompt that counts the ram and gives you system info before the OS starts.
Sounds like your motherboard is the problem, although your CPU could be fried too.
Does anyone here think it could be the system timer?
i had the same prob where i turned on the comp and the lights flashed indicating the hard drive was being accessed, but it wouldnt post and there was no signal to the monitor. i replaced every single component in there and nothing worked. it turned out the mother board was fried. had to replace it. by the way, compaq sucks, there case wouldnt fit a new board, so i had to get a new case too
02-22-2001, 09:08 AM
Thanks again for the help and suggestions, it looks like the next step is to replace the motherboard. Any suggestions on what I should buy to replace it and which vendor I should buy from? The motherboard I have now is an Epox 82430TX PCIset model P55-TX 2. Easy to understand documentation is a necessity because I'm a novice and this will be my first attempt at replacing a motherboard.
02-22-2001, 12:07 PM
Before you go replacing the board try jumping the bios reset jumper. If you have your motherboard manual look it up, or consult the manufacturers web site.
I am not familiar with that board, but I have had TX boards before and they did normally have a jumper to reset the bios to it's base values.
Don't get me wrong, it does sound like your motherboard power regulator is fried, but do the easiest thing first.
The regulator has a transistor on it, with a heatsink. They are normally situated near the cpu socket--there might be two of them. If there is any discoloration on the motherboard or heat sink that is a sure sign of it being toast.
02-22-2001, 09:54 PM
Bandito, thank you. I looked up the reset jumper in the motherboard user's manual and tried jumping it, no change, but when I looked closely I noticed there is a discoloration on the motherboard next to the cpu, so it would seem like the motherboard is the problem.
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