Is this voltage too high??

Question

Alright..classic 14" Ibook no backlight problem.
Tested the inverter cable - cable good.
Tested voltages going to inverter board: (Should be 0, +5, +12, and 1.5-3.5, from what I've read). Mine test: (0, +5, +16, +3.5ish)
I replaced the inverter board and still no backlight.
Before I replace the CCFL lamp, I just want other people's opinions whether the 16volts is too high, and maybe that's burning out the inverter board or the lamp?
What do you think? Is 16 ok? Should I order a bulb and try that next or would I be wasting my money?
Thanks in advance.

Answer 1

OK Rob,
Here's the troubleshooting from the 14.1 1.42 Service Manual:
"Display
No display, or dim display, but computer appears to operate correctly (if dim,
display shows startup icon and/or desktop)
1. Remove any connected peripherals.
2. Try known-good power outlet, power adapter and power cord.
3. Press F2 (with the fn key pressed and not pressed) to increase the screen brightness setting.
4. Reboot the computer—hold down the Control and Command keys and press the
Power button, or press and hold the Power button for 5 to 10 seconds to shut down the computer, then press the Power button to restart.
5. Reset the power manager by pressing the key combination Control-Option-Shiftpower.
Warning: Make sure you do not hold down the "fn" key when resetting the
power manager.
Warning: Resetting the power manager means you will also need to reset the
date and time (using the Date & Time control panel)."
6. Reset PRAM (Press the power button, then hold down the Option-Command-P-R
keys until you hear the startup chime at least one additional time after the initial
startup chime).
7. Connect an external display, and check for video on external display.
• If video is fine on external display, troubleshoot LCD panel and verify cable
connections to inverter and LCD.
• If video symptom is same on external display, replace logic board."
That would imply a GPU error
"8. Verify backlight cable and LVDS cable connections are seated properly and that the
cables are not damaged (refer to display assembly replacement instructions)."
I flex the cables near the hinge point to do this check. Especially pushing them into compression (to make any broken connections)
"9. Replace LCD panel.
10. Verify cable connections and check cables around the hinges for damage.
11. Replace logic board."
1 black and 1 grey wire which I believe are the airport antenna, and a black wire for the microphone.
Also from the Manual:
"From the bottom of the bezel brace, note the routing of the black and gray antenna cables."
So those sound like the Bluetooth and Wireless antenna cables.
The LVDS cable is bundled with the mike (black) cable and is fat and gray.
Richard
Message was edited by: spudnuty