Re: ASUS N56VM dead
I'm not being lazy, I have the boardview but no circuit!
Looking at the repair guide, there's a power switch marked EMB07P03G, obviously a MOSFET, but where is it on the board? It is shown as having A/D_DOCK_IN, AC_BAT_SYS, and CHG_ACIN_OK# signals, the latter isn't even in the Boardview file, and I can't find any component that has the 1st two signals on it.
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ASUS N56VM dead
I have an Asus N56VM with the N56VM Mianboard V2.3; the computer is dead with no lights on at all.
I have measured 19.3V on A/D_DOCK_IN, but I'm only seeing 0.76V on AC_BAT_SYS. There is no 3V at the power switch, so I'm clearly missing the standby rails. I do not have a schematic, just the repair guide and the board files; can someone tell me where to look for the source of the standby supplies?
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Re: Acer Aspire R3-131T no backlight
My measurements around Q5202 and Q5203:
Q5202 G2 (5) 3.3V, S2 (4) 0.0V, D2 (3) 0.0V
Q5203 B 0.0V, C 3.3V, E 0.0V
With R5257 removed, its pads measure:
5 0.0V, 7 3.3V, 8 3.3V
So eDP_BLCTRL_CPU is really missing (low) and R5257 is OK, so I'm no further forward! Resistance readings on eDP_BLCTRL_CPU indicate that the trace is connected to the CPU, so I suspect something else is amiss; I'm now contemplating setting eDP_BLCTRL_CPU permanently high as you suggest.
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Re: Acer Aspire R3-131T no backlight
Acer R3-131T (Wistron Chopper 1-14299-1) schematic.
[ATTACH]207000[/ATTACH]...
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Re: Acer Aspire R3-131T no backlight
Oh, you mean the schematic, I'll put it up a little later.
OK, so eDP_BLCTRL_CPU_R is being held low by Q5202 because pin 5 is high as a result of Q5203 being off; Q5203 is off because eDP_BLCTRL_CPU_Q is low due to eDP_BLCTRL_CPU being low....
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Re: Acer Aspire R3-131T no backlight
All the resistors check out with the values on the schematic. The voltage readings on eDP_BLCTRL_CPU, Q5203 and Q5202 are all exactly the same with the panel connected. I also checked the Hall sensor with a magnet and confirmed the LID signals do change, going low when the magnet is brought near the sensor. It seems the output from the CPU isn't correct.
Datasheet for the Hall sensor is attached.
[ATTACH]206937[/ATTACH]...
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Re: Acer Aspire R3-131T no backlight
LID_CLOSE1# and LID_CLOSE2# read high with the lid open which appears to be correct if I'm reading the datasheet for the Hall sensor correctly.
eDP_BLCTRL_CPU reads 230k to gnd, so no sign of a problem there (readings taken with the panel disconnected). The FET Q5202 and bipolar Q5203 appear to be functional.
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Re: Acer Aspire R3-131T no backlight
eDP_BLCTRL_CON is low because eDP_BLCTRL_CPU is low, now I am stumped because I can't track the signal back further than R5227 as the next point that the signal surfaces at is below the CPU package.
Update, I managed to locate the trace at the unoccupied R804 pad, eDP_BLCTRL_CPU is low there as well.Last edited by CambridgeMart; 02-09-2020, 09:20 AM.
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Re: Acer Aspire R3-131T no backlight
Thanks, that's what I needed to know....
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Acer Aspire R3-131T no backlight
I'm trying to repair an Acer R3-131T which has display problems. The panhel is working as I can see an image if I hold a bright ligtht up to it, but the backlight is dead. I've checked the signhals on EDP1 and I have +16V on 37-40, +3.2V on eDP_BLEN_CON (pin 34) and +0.5V on eDP_BLCTRL_CON (pin 35).
I don't know what signal levels should be on 34 and 35, so not sure if I should be fault finding the mainboard or the display.
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