Question about Computers & Internet

2 Answers

Power light goes out but power remains thru the m-board fan runs

But no power thru usb ports or video monitor; reset pmu switch; replaced battery; red light on mother board remains on; fan speeds up and slows down heat coming off prossesor; if i hold down power button for 5 to 10 sec power shuts off hit power button again power comes on but light goes off tried all combonations on key board to trigger a restart but i dont think the key board is registering no lights come on the key board ;unplug the monitor from the computer and it says cable unpluged plug it back in and and the monitor goes back to sleep ....//////please help??????

Posted by on

  • Luke Kim
    Luke Kim May 11, 2010

    now this is with a desktop not a laptop right?

    and the key combo for a reset is Command + Option + Power Button. Thats the equiv.. to a Ctrl + Alt + Del on a windows system.

    But does you mac turn on and load to the desktop? or does it just start up and hum, and nothing on screen and all peripherals don't respond as well?

    If that is what you are getting then the power supply needs to be replaced. I've had that same issue once with my PowerMac G4 Dual Proc.

    (ya i know you can start up and the fan hums and all but thats the fan for the power supply not the fan for the board. if you have a older mac the cost for a new power-supply shouldn't be that much. And you can probably order it and replace it yourself.
    a good cheap place i've found so far is here:
    http://stn2.headgap.com/resale/FMPro?-db...

×

2 Answers

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

My mac G5's screen goes dark when i'm on the web and the fan sounds like it is trying to turn on but stops as the screen goes dark. When I click and pick up the mouse to get the screen back on I notice the mouse light is off, than it flashes on as does the screen......this happens frequently. its it the mouse, light board or power board?? help

Posted on Jan 30, 2010

  • Level 1:

    An expert who has achieved level 1.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that hasĀ over 10 points.

    Mayor:

    An expert whose answer gotĀ voted for 2 times.

  • Contributor
  • 21 Answers

You need to replace the power supply. The fan sound is the fan for the power supply and not the computer. for cheap parts or used goto headgap's. They know what you need and probably even help you replace it yourself.

Posted on Jul 07, 2009

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Lights come on and stay on, screen stays black and no bios


Hi.

First try resetting the laptop by removing battery with computer off and power not connected. Ensure that there is no disk inside the laptop and no connected USB device.

Test the laptop using an external display. There should be a video port at the back or at one side of the laptop. You may need to use a function key or to restart the laptop with the external monitor connected to switch to the external monitor.

If the laptop has picture in the external monitor, then the problem is either the back-light inverter or the LCD display. The inverter is the board that supplies power to the display and it is often located at the base of the display. Inverter is tested disassembling the computer and reading DC in from main board to inverter and AC high voltage out from inverter to back light.

If there is no picture on the external monitor, then the main board is probably faulty. The main board is tested disassembling the laptop and starting with no disks or internal devices connected (apart CPU fan, adapter and display) and replacing the memory sticks with known good ones. If the computer has two memory sticks, it can be tested removing them one at the time.

Testing must be done by a technician.

Regards.

Ginko

Apr 30, 2011 | Computers & Internet

1 Answer

MY MAC G5 IS NOT BOOTING . WHEN I PUSH THE POWER ON SWITCH THERE IS A BEEP TYPE SOUND AFTER FEW SECONDS AND THEN SPEEDY FANS NOISE IS HEARD.AND INSIDE I SEE RED LIGHT GLOWING


p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Times; color: #1a1a18} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Helvetica; color: #1a1a18} span.s1 {color: #0066a4} span.Apple-tab-span {white-space:pre}

Power-on LED illuminates when power button is pressed, fans spin, and boot tone chimes, but there is no video


1. Reseat video card. (Make sure video card is fully inserted in connector and end of card is secured by the connector latch.)

2. Reset PRAM (restart computer while holding down Command-Option-P-R keys until second boot tone chimes)

3. Replace video card

4. Reset logic board. Refer to "Resetting the PMU on the Logic Board" in this chapter.

5. Replace logic board



p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; color: #1a1a18} p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Helvetica; color: #1a1a18} span.s1 {color: #0066a4} span.Apple-tab-span {white-space:pre}

Resetting the PMU on the Logic Board

The PMU (Power Management Unit) is a microcontroller chip that controls all power functions for this computer. The PMU is a computer within a computer. Its function is to:

tell the computer to turn on, turn off, sleep, wake, idle, etc.

manage system resets from various commands.

maintain parameter RAM (PRAM).

manage the real-time clock.


Important: Be very careful when handling the logic board. The PMU is very sensitive and touching the circuitry on the logic board can cause the PMU to crash. If the PMU crashes and is not reset, the battery life goes from about five years to about two days.


1. Disconnect the power cord and check the battery in the battery holder. The battery should read 3.3 to 3.7 volts. If the battery is bad, replace it, wait ten seconds, and then proceed to step 2. If the battery is good, go directly to step 2.


2. Press the PMU reset button once and then proceed to step 3. Do not press the PMU reset button a second time because it could crash the PMU chip.


3. Wait ten seconds before connecting the power cord and powering on the computer. If the computer does not power on, there is something else wrong with it; refer to the "Startup Failures" section of "Symptom Charts" in this chapter.

Note: The above procedure resets the computer's PRAM. After resetting the PMU, be sure to reset the time, date, and other system parameter settings.

Dec 11, 2010 | Apple Power Mac G5 Desktop

1 Answer

I hooked hdmi to tv. i went thru ps3 settings for video n audio n swithch audio to the red n white output. now i have sound thru surround sound but my video is flickering n i cant c so i can undo it


Make sure the Component AV Cable is connected to the AV Multi Out port on the back of the PLAYSTATION 3 system. Connect the other end of the Component AV Cable into the video and audio RCA jacks of the TV or display monitor.

2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive On/Off button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light to --> green light --> then back to red light) This will ensure that you have held down the ON/OFF button long enough to reset the Video Output Settings.


3. Turn on the PLAYSTATION 3 system and once the system finishes powering up, the Video Output Settings will automatically be reset to the standard resolution (or detect the current display output settings of your TV/monitor).

Jul 01, 2010 | Sony Playstation 3 (PS3) Console

1 Answer

The PS3 switches on, lights up, drive and disc drive working but No Signal on TV. Saw HDMI cable solution previously posted. Does that work for SCART also?


yes just change hdmi for the word scart
  1. Make sure the HDMI cable is connected to the HDMI OUT port on the back of the PLAYSTATION 3 system. Connect the other end of the HDMI cable into the HDMI Input port of the TV or display monitor.
  2. While the PLAYSTATION 3 system is in standby mode (red light on the front of the system), hold down the touch-sensitive power button on the front of the system until the system goes into standby mode again . (So the light cycle would go from: red light --> green light --> then back to red light). This will ensure that you have held down the power button long enough to reset the Video Output Settings.
  3. Turn on the PLAYSTATION 3 system and once the system finishes powering up, the Video Output Settings will automatically reset to the standard resolution (or detect the current display output settings of your TV/monitor).


Jun 30, 2010 | Sony Playstation 3 (PS3) Console

1 Answer

IBook G4 battery charging, but won't power on


Stupid question but did you remember to reconnect the start up switch to the logic board? Also check to make sure you did not break the connector loose from the logic board.

Jun 09, 2009 | Computers & Internet

1 Answer

Machine shuts down, might start again in a day or so


This may solve your issue:

The PMU is a microcontroller chip that controls power functions for the computer. The PMU is a computer within a computer, as it has its own memory, software, firmware, input/output, a CPU, and more. Its function is to:
  • Tell the computer to turn on, turn off, sleep, wake, idle, etc.
  • Manage system resets from various commands.
  • Maintain parameter RAM (PRAM).
  • Manage the real-time clock.
Over time, the settings in the Power Manager may become unusable, which can result in operational anomalies with the computer. Examples include not turning on, not waking from sleep, or not seeing devices plugged into the USB and FireWire ports, among others.
Resetting the PMU is not intended for resolution of a stall or situation in which the computer is unresponsive. A PMU reset should not be necessary except as a last resort in cases where a hardware failure of the power management system is suspected. Performing a PMU reset returns the computer hardware, including NVRAM, to default settings and forces the computer to shut down.


http://support.apple.com/kb/HT1939

Click on this link or copy and paste the complete link into your browser.
If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe

May 16, 2009 | Apple iBook G4 Mac Notebook

1 Answer

G4 Aluminum Powerbook 15in 1.5ghz will not power up :(


Have you solved your problem.
Since you are taking it apart look at the folowing:

PMU reset:

The PMU is a microcontroller chip that controls power functions for the computer. The PMU is a computer within a computer, as it has its own memory, software, firmware, input/output, a CPU, and more. Its function is to:
§ Tell the computer to turn on, turn off, sleep, wake, idle, etc.
§ Manage system resets from various commands.
§ Maintain parameter RAM (PRAM).
§ Manage the real-time clock.
Over time, the settings in the Power Manager may become unusable, which can result in operational anomalies with the computer. Examples include not turning on, not waking from sleep, or not seeing devices plugged into the USB and FireWire ports, among others.
Resetting the PMU is not intended for resolution of a stall or situation in which the computer is unresponsive. A PMU reset should not be necessary except as a last resort in cases where a hardware failure of the power management system is suspected. Performing a PMU reset returns the computer hardware, including NVRAM, to default settings and forces the computer to shut down.
http://support.apple.com/kb/HT1939
Click on this link or copy and paste the complete link into your browser.
If I could be of further assistance, let me know. If this helps or solves the issue, please rate it.
Thanks, Joe



Apr 01, 2009 | Apple PowerBook G4 Mac Notebook

2 Answers

My ibook g4 doesn't start up


Is the power adapter the correct voltage?
Does the battery show that it's charging?
If the answers to these are both 'Yes' then remove the battery and try to start up again. If this works, reinstall the battery and everything should be fine.
Another possibility is that you may need to reset the PMU.
If none of these work, you may need to replace the Power Board/Power switch/Logic Board.

Jan 03, 2009 | Apple iBook G4 Mac Notebook

2 Answers

Powermac g4 will not turn


this is a common problem with G4 Quicksilver. Your power-supply is defect and has to be replaced. I have 4 G4s in my lab with the same symptom: a short flash of the power-button light, sometimes it turns on, but mostly the machine is dead.
Richard

May 07, 2008 | Apple Power Supply 344 Watt PowerMac G4...

2 Answers

When turning on my macbook pro


Please clean-up the RAM modules wiping it with a dry cloth and re-insert it back into its slot .

May 06, 2008 | Apple MacBook Pro Laptop Computer with...

Not finding what you are looking for?
Computers & Internet Logo

Related Topics:

582 people viewed this question

Ask a Question

Usually answered in minutes!

Top Computers & Internet Experts

Doctor PC
Doctor PC

Level 3 Expert

7733 Answers

kakima

Level 3 Expert

102366 Answers

David Payne
David Payne

Level 3 Expert

14161 Answers

Are you a Computer and Internet Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...