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| acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd https://vlab.su/viewtopic.php?f=59&t=20604 |
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| mohkam3000 [ 10 апр 2014, 03:34 ] | |
| Заголовок сообщения: | acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd |
Hi! acer aspire 7750 display is ok on external monitor, but dim on led lcd. Main Voltages measured on JLVDS1 connector pins : +INVPWR_B+ : 21V Local_Dim_R : 0.8 to 1.1V INVTPWM : 3.6V +3VS : ok +LCDVDD : 3.6v +5VS : ok But BKOFF# : 0V ??? I guess that BKOFF# should be around 3v to enable backlight. Isn't true ? BKOFF# issued from EC kb930QF to JLVDS1 pin6 is supplied with 3VS through R342 (10k) and grounded through R15 (10k) // C6. BKOFF# resistance to ground measured about 4 ohms ?? Though I desoldered C6, resistance remained the same. Does I have to replace the EC to get BKOFF# high and led backlight enabled? Please advise further. Thank you |
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| vdklv [ 10 апр 2014, 14:28 ] | |
| Заголовок сообщения: | Re: acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd |
measured BKOFF# without LVDS cable? powered on/off? |
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| mohkam3000 [ 10 апр 2014, 14:39 ] | |
| Заголовок сообщения: | Re: acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd |
Wish to correct "Does I have to replace the EC to Get High and BKOFF # LED backlight enabled?" Does I have to replace the EC to Get BKOFF# High and LED backlight enabled? |
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| vdklv [ 10 апр 2014, 16:32 ] | |
| Заголовок сообщения: | Re: acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd |
My question refers to check the LCD cable, because you have not written about resistance to ground measured 4 ohms with cable or not. And about your question:yes |
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| mohkam3000 [ 10 апр 2014, 18:55 ] | |
| Заголовок сообщения: | Re: acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd |
vdklv писал(а): My question refers to check the LCD cable, because you have not written about resistance to ground measured 4 ohms with cable or not. And about your question:yes hi BKOFF# resistance to ground is 4 ohms without cable. cable continuity checked ok. |
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| mohkam3000 [ 26 апр 2014, 01:20 ] | |
| Заголовок сообщения: | Re: acer aspire 7750 (LA-6911P rev:1.0) dim display on lcd [РЕШЕНО] |
This feed back might help other members. Issue solved. Found E/C BKOFF# pin shorted, and R342 supplying BKOFF#pin with 3vs missing. |
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