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(Created page with "{{stub}} {{Repair Guide |Device= |Affects parts= |Needs equipment= |Type= |Difficulty= }} ==Problem description== Troubleshooting Alienware M18x R2 missing backlight. This machine mounts Compal LA-8321P board. This post applies to other machines, with different motherboard, but using similar backlight control. thumb|Q45 circuit (Figure 1) ==Symptoms== *No backlight on LCD ==Solution== ''Make sure the problem is no backlight and no...") |
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{{Repair Guide | {{Repair Guide | ||
|Device= | |Device=Alienware M18x R2 | ||
|Affects parts= | |Affects parts=Motherboard | ||
|Needs equipment= | |Needs equipment=multimeter, soldering iron, soldering station | ||
|Type= | |Type=Soldering | ||
|Difficulty= | |Difficulty=3. Hard}} | ||
}} | |||
==Problem description== | ==Problem description== | ||
Troubleshooting Alienware M18x R2 missing backlight. This machine mounts Compal LA-8321P board. This post applies to other machines, with different motherboard, but using similar backlight control. | Troubleshooting Alienware M18x R2 missing backlight. This machine mounts Compal LA-8321P board. This post applies to other machines, with different motherboard, but using similar backlight control. | ||
Latest revision as of 18:00, 25 November 2023
| Alienware M18x R2 No backlight repair | |
|---|---|
| Device | Alienware M18x R2 |
| Affects part(s) | Motherboard |
| Needs equipment | multimeter, soldering iron, soldering station |
| Difficulty | ◉◉◉◌ Hard |
| Type | Soldering |
Problem description
Troubleshooting Alienware M18x R2 missing backlight. This machine mounts Compal LA-8321P board. This post applies to other machines, with different motherboard, but using similar backlight control.
Symptoms
- No backlight on LCD
Solution
Make sure the problem is no backlight and not no image!
See Fig. 1.
Very likely we find +INVPWR_B+ is not present. We must assure no short to ground w/ and w/ LCD connected.
Next will check LCD_BKL_EN signal. If present (3V), then check R423 voltage on both pins. Getting 0V at pin 2 assures Q44 works correctly. 19V there suppose bad Q44; need to change it. If we get 0V at pin 2, but 19V at pin 1 (PWR_SRC_ON), 99% Q45 is bad; replace it. Is still possible (very low chance) to have bad C346 (corroded), or R423 (open).