Dim backlight CCFL Ok...
Best method (s) turning lamp current up without letting the white smoke out based on this diagram. not using SMBus Host.
Attached Files
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I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered... -
Design of CCFL Backlight Inverters with Frame & Bar Cores
Summary
Portable devices, such as notebook computers and personal digital assistants are developed rapidly nowadays, which places an increasing demand on display technology. The LCD with cold cathode fluorescent back lighting satisfies the requirements on display performance, size and efficiency.
The backlight inverter plays a crucial role in supplying the power to the lamps of these flat-panel displays.
The frame and bar ferrite cores, described in this brochure, are especially designed...10-07-2024, 04:26 AM -
this tv is throwing me for a loop. do samsung tvs no longer have the backlight self test feature built into the power supply?
i tested the backlight with my LED tester and it lights up both strips. one of them reads 100v and the other reads 63.7v.
unplugged mainboard from power supply but left backlight plugged in, and then plugged psu wall power in. expected to see backlights light up but see nothing.
according to how ive diagnosed in the past, this would almost always be a bad power supply. replacement power supply was cheap like 20$ from ebay. but still i get not even... -
Hello all,
Am trying to figure out this backlight issue with this A1990 Macbook Pro.
Tests performed:
There is no backlight even with a good screen.
Backlight IC is receiving the correct support voltages.
Fuse F8400 ok
Current sense resistor R8400 ok
Backlight IC is receiving 3.3V on enable pin.
Backlight IC receiving voltage from PPBUS_G3H, aprox 12.5V.
Backlight IC receiving 5V from PP5V_G3S
Backlight IC BKLT_SCL and BKLT_SDA both measure 0.545V diode mode to ground
I2C_BKLT_SCL and I2C_BKLT_SDA both measure... -
Hello, got an iPad Pro A2378 12.9 5th gen with no backlight. Got another test unit without screen, tested the screen, still no backlight with the test unit.
Figured out the backlight on the screen was bad, ordred a new backlight from mobilesentrix, *carefully replaced it* without damaging the lcd, oh well.
Final result, issue is still there, the screen has no back lights. So i'm back to square one, with 3 hours less and 100$ out, issue still on the screen.
The panel is still ok, i can see the apple in the middle of the screen when it kicks in, just no backlight.
Anyone...