pc power supply
- Thread starter inkjunkie
- Start date
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TrailBeast
AKA Mopars4us on Youtube
Most of the newer style power supplies (ATX) wont have full power to the mainboard until the power switch tells the power supply to come on.
When that happens to a customer, I tell them to unplug the computer and push the on button 6-8 times with it unplugged.
Then plug it back in and try to turn it on.
(Sometimes fully draining the capacitors in the PS and then repowering them will make the computer come on again)
If you do that and it comes on again it's def the power supply.
It is a safe bet that it is anyway though.
Look at the capacitors on the motherboard first though, and if any of them are leaking it is probably the mainboard and not the power supply.
They are probably different colors than these, but the stuff on the tops is capacitor guts.
Looked for swelled top on them also.
Most of the time I can fix a motherboard that has this problem and it works fine again.
Same with power supplies (same caps, same fix)
When that happens to a customer, I tell them to unplug the computer and push the on button 6-8 times with it unplugged.
Then plug it back in and try to turn it on.
(Sometimes fully draining the capacitors in the PS and then repowering them will make the computer come on again)
If you do that and it comes on again it's def the power supply.
It is a safe bet that it is anyway though.
Look at the capacitors on the motherboard first though, and if any of them are leaking it is probably the mainboard and not the power supply.
They are probably different colors than these, but the stuff on the tops is capacitor guts.
Looked for swelled top on them also.
Most of the time I can fix a motherboard that has this problem and it works fine again.
Same with power supplies (same caps, same fix)
67Dart273
Well-Known Member
As TB and Red said, this could be a MB or start button problem. If you Google around, "there used to be" a checkout procedure where you could "start" them separate from the MB
Some PS like Dell are proprietary and are "not quite" the same as generic ATX
This one here seems pretty fair
http://marcomiltenburg.com/2011/09/18/how-to-test-an-atx-power-supply/
https://www.google.com/search?num=3....0....0...1c.1.37.serp..1.20.1066.ur_9hEhqH64
Some PS like Dell are proprietary and are "not quite" the same as generic ATX
This one here seems pretty fair
http://marcomiltenburg.com/2011/09/18/how-to-test-an-atx-power-supply/
https://www.google.com/search?num=3....0....0...1c.1.37.serp..1.20.1066.ur_9hEhqH64
TrailBeast
AKA Mopars4us on Youtube
Every point made here is right on the nose guy's.
I was going to keep it simple at first and see how things progressed.
67 Power Wagon
Hemi Pawr or BUST!
got a picture of the actual Power Supply? I may have a replacement if you need one, for a better price then you'll get with a new one!
Let me know PM me!
Let me know PM me!
trapster
Well-Known Member
power supply checkers are cheap check ebay
inkjunkie
Well-Known Member
As TB and Red said, this could be a MB or start button problem. If you Google around, "there used to be" a checkout procedure where you could "start" them separate from the MB
Some PS like Dell are proprietary and are "not quite" the same as generic ATX
This one here seems pretty fair
http://marcomiltenburg.com/2011/09/18/how-to-test-an-atx-power-supply/
https://www.google.com/search?num=3....0....0...1c.1.37.serp..1.20.1066.ur_9hEhqH64
Pulled the plug off of the mb and paper clipped it. All voltages were "normal"...power button on front of box done for?
Viper21700
Well-Known Member
Not necessarily.. On ATX motherboards, its actually not the power switch that turns on the power supply. The computers motherboard's bios actually send a signal to turn the power supply on. If the motherboard is shot it wont turn on. Also- if any of the internal components are shot it will prevent the power supply from turning on. Best way to test is to disconnect power from every component except the motherboard, try to power on. Then find a friend with a good computer, try to swap power supplies (don't even have to remove from case, the cables should be long enough to reach between the computer cases if close together) then test your motherboard off his power supply. That's the cheapest way to test. Usually the way I do it on ship if some dingle berry misplaced my test equipment...
Viper21700
Well-Known Member
Also- if the switch is the problem, find the two pins the power switch plugs into on the motherboard, take a small flat headed insulated screw driver and short them together, which is what the switch is doing in all actuality.
inkjunkie
Well-Known Member
Took the front of it apart to get to the power switch...pulled back the shrink tubing and touched the two power switch wires together with a paper clip....nada...it still no run....
Daves69
Well-Known Member
Can you trace those two wires to where they attach to the board? They are likely next to each other where they connect. You could try to momentarily short those two posts (and only those two) to rule out the switch and it's wiring.
67Dart273
Well-Known Member
The above^^^ These are many times connected to the board with a simple two wire connector. Just pull that off to eliminate the switch, and try shorting those clips
ALSO TRY this:
Find the bios battery, which many times is a "coin" battery. Remove from the board and let it sit awhile. I usually short the bios battery mount connections with a clip lead to discharge. This will reset the bios to "default" and you may have to make changes later
Then see if it will start. If not, pull loose all accessories power. That is, disconnect the monitor, keyboard, everything from the outside except the power plug
Pull loose all drive connectors, hard drive(s), CD/ DVD drives, floppy drive, etc.
See if the PS fans come to life.
Only now can you finally say "it's either the MB or the PS"
Next step is to do the tests posted earlier, "start" the PS as posted earlier
jtolbert
Well-Known Member
Unplug the power cable from the PSU or the wall, or just turn the switch on the PSU off, hit the power button on your machine, turn the PSU back on or plug it back in and hit the power button again. I've seen PSUs get "weird" every so often; this little trick has worked for me several times.
Hold the 'Insert' key while powering the machine on. Sometimes this forces BIOS to default memory timings and such, which can occasionally get a machine to a debuggable stage again.
Clear CMOS via jumper on motherboard. Pulling the BIOS battery is an option, but I've also had to replace battery holders on motherboards cause someone screwed up the tabs in the battery holder. I think new ones are a lot less problematic than old ones, though.
After that, you're going to be unplugging things, removing all but one stick of RAM, removing any expansion cards outside (and maybe including) the video card, and so on. You can plug in another power supply while leaving it sitting outside the case to test with.
Hold the 'Insert' key while powering the machine on. Sometimes this forces BIOS to default memory timings and such, which can occasionally get a machine to a debuggable stage again.
Clear CMOS via jumper on motherboard. Pulling the BIOS battery is an option, but I've also had to replace battery holders on motherboards cause someone screwed up the tabs in the battery holder. I think new ones are a lot less problematic than old ones, though.
After that, you're going to be unplugging things, removing all but one stick of RAM, removing any expansion cards outside (and maybe including) the video card, and so on. You can plug in another power supply while leaving it sitting outside the case to test with.
inkjunkie
Well-Known Member
Wires from the power switch are part of a 12-14 wire plug. Took a piece of mig wire and jumped the power switch wires at the board....nada...pulled the bios battery, let ti sit over night. Still nada....Unplugged everything, plugged it in and tried jumping at the board again...still nada....Checked the "atx" plug as described above.....all had the proper amount of power....
67Dart273
Well-Known Member
Starting to sound like MB. Some MBs wont' fire at all if memory, or CPU is not making proper contact. I have not kept up with CPUs but some of the new ones are VERY VERY easy to eff up. I bought one "was lucky." It was a cheap Dell Hell, and a clip had broke holds the CPU in place. I forget............the fan? housing hand fallen inside. Anyhow, CPU came loose. It was OK, and "I don't know why."
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