Computer dosent turn on..screen is blank with blinking LED
Hello, i recently was testing a voltage regulator power supply i had built with software running on my computer throught the parallel port. The software tests if the LEDs on my power supply would light up according to the voltages (12v,3v,5v,..) I was moving the board around because some seemed to be lighting while i was doing it. Then a big spark came out of the curcuit board and my computer breifly stoped ( no power, no screen, no nothing) for about 5 seconds. It then came back on how it was originaly. When i tried typing the keyboard didnt work but the mouse did. So i rebooted the computer pressing the reset button. When i try to turn on the computer the power button dosent work only the reset button works. It only comes on when i switch the power switch at the back and the screen turns on but its just black with a blinking light like its on standby.
I tryed to give as much info as possible
Please Help Me!!
Re: Computer dosent turn on..screen is blank with...
Have u tryed unplug all of your plugs at the back like blow on them like i do to get lil partcals of dust out then plug all back in and mite work or maybee ur power cord is screwed a bit and u mite have to get a new one whats happednd to ur comp happend exactly the same with mine and i screwed with myn for ages and it finaly worked so maybee just try all that n then if that dosent work as drliativ hes a good guy and will help
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If it uses a A/C power adapter aka (power brick) that the first thing I would check.. if you have voltmeter you check the voltage to make sure it's at least rated at or above the sticker value, if not try replacing it. If it uses a standard computer power cord and the power supplies is built-in to the monitor it might be bad or the main board has gone bad. Those most common cause in the that order power supply or mainboard.
many LCD Monitors have thermo regulator kill switches built into them to keep the screen from cooking the internal components when they get to hot.Most likely the regulator is bad (oh and by the way I don't think that is their actual name) or what ever is supposed to be keeping the boards inside cool is on the fritz. either way you would need to find out which part is actually broken and replace it, or maybe better ventilate your monitor and put a fan behind it to keep it cool. some monitors will give an error code in the form of a blinking power button (different counts of blinks for different codes) if it is giving you one you might be able to pin point the problem and fix it ;)
Test the monitor on another computer, to eliminate the possibility that the computers graphics chip or card may have failed. Also if possible, test the computer with another monitor.
Assuming that the graphics card, the VGA cable and the power lead to the monitor are all working and in good condition, you are most likely ( as evidenced by the flashing led light), experiencing a protection state.
This means that you either have a situation where the internal chip on the monitor control board is reading the wrong voltage, or the
You need to check on the cable that is connecting your computer and the monitor. Usually you encounter this problem when the monitor is not getting any signal from the computer. Try other VGA cables if you have spare monitor in your area.
Let me know how it goes.
Check the volatage regulator in the mainboard resolder all you found dried unsolder parts inside mainboard. Voltage test the regulator IC if have a voltage flow 2.5 to 5v DC. check ribbon cable connector from mainboard to controller board if properly connected. In the controller board find the small fuse test it for open. Reminder:
When you voltage test in the power board
in the primary section of power supply
use hot ground. Do not use the hot ground
when you voltage testing the secondary
power supply, mainboard and controller
because it will cause of damage
semiconductor. For safety use cold ground
for secondary, mainboard and controller
Self-Test Feature Check (STFC)
Your monitor provides a self-test feature that allows you to check whether your monitor is functioning properly. If your monitor and computer are properly connected but the monitor screen remains dark, run the monitor self-test by performing the following steps:
Turn off both your computer and the monitor.
Unplug the video cable from the back of the computer. To ensure proper Self-Test operation, remove Analog (blue connector) cables from the back of computer.
Turn on the monitor.
The floating 'Dell - self-test Feature Check' dialog box should appear on-screen (against a black background) if the monitor cannot sense a video signal and is working correctly. While in self-test mode, the power LED remains green and the self-test pattern will scroll through the screen continually.
Turn off your monitor and reconnect the video cable; then turn on both your computer and the monitor.
If your monitor screen remains blank after you use the previous procedure, check your video controller and computer system; your monitor is functioning properly.
Sounds like an inverter problem. If the power supply is internal replace the capacitors coming out of the voltage regulators. These are usually 1000mf and/or 470mf. If that doesn't do the trick look up the numbers on the 8-pin chips that drive the secondary transformers on the inverter to see if they are getting the right voltages. Good Luck!
Explicit enough to see that's this a a repair shop job. That also probably means a replacement- cost of which will not be much more than repair prices.
One thing how ever- the power supply[which would appear to be the problem] is this built into the screen [that is does the screen have mains power direct? Or is it powered from an external 'Power Brick'
If it is of the Power Brick type - then a new power supply is the answer - get on of the stabilized universal type with a fistful of connectors and a voltage selector switch.