Trying to replacing Aspire V3-112P panel with a better one

Hello everyone!


I have an Acer Aspire V3-112P (marketed as "V11 Touch" at the time) that I use for my mobile needs. It's nothing impressive on the hardware side, but sufficient for my needs (remoting to my home and work station).

Recently I got my hands on a 1080p panel with better specs than the laptop's built-in one (N116HSE-EJ1 vs B116XTN01.2) and wanted to swap them around, but of course it wasn't as simple as a drop-in replacement.

With the new panel connected the system boots up but doesn't show anything. The backlight turns on at power on but off during windows boot (I'm assuming when the gfx driver is loaded). With a second monitor connected through HDMI, I can see the panel being correctly detected in the Intel HD Graphics Control Panel (identified as CMN1126), but the only display mode available is "second screen only". When I try to switch it to mirror/extended, it goes back to external monitor only.

The only cause I can think of for this is that the FHD panel requires 2 eDP lanes, but only one is currently wired. Unfortunately, as much as I searched, I wasn't able to find out if it's just the display cable missing the required wires or the mobo doesn't even have the required pins traced to the connector (the motherboard uses the same 30pin connector, but the cable connected to it splits out to the panel, webcam and digitizer, so I don't know if there are enough pins left for the second lane).

So here is my question: Does anyone know where I could find the pinout for the motherboard connector, to see if this upgrade is possible (DMI reports it as Acer R2 Type2 - A01 Board Version) ?

I also thought of trying a different cable, from a different model (this series only comes with 1366x768 panels), as Acer has other 11" laptops with 1080p displays (the Aspire S7-191 even seems to come with the exact FHD panel I have), but I'm a bit wary that pin order might be completely different and at best I'd be investing in a cable that doesn't do anything, but is actually likely to burn the video card and/or panel. Does anyone know if Acer have any consistency in their layouts/pin order across models?


Thanks in advance to any kind soul that can help me in this quest!

 

That is quite common.

That stock panel looks terrible, so a nice improvement. Acer isn't known to distribute schematics, better search the motherboard for the Compal number. Also, make photo of the connector on the mb and lcd end. Might have to pull back the wrapping a bit, that way all the individual wires will be visible and the non-connected pins can be counted. The absolute minimum for 2-lane would be ~15 pins (depending on backlight voltage and bl brightness). Add 4-6 for webcam and 10-15 for digitizer; it'll be a close call. Fortunately, the difference between 1- and 2-lane is only 3 pins (minimum). If ' Switch 11 SW5' lcd cables are split-off type then there isn't much hope, unless your mb has a secondary connector too. If so, then you might be able to sacrifice touch, yet keep the fhd.

That is, indeed, a possibility. However, customisable cables+connectors exist, allowing you to swap the wires to the correct pins.

 

Thank you for the information.

I opened the laptop to get all the required information, but then actually forgot to look at the mobo connector as well, just the display one, which has 14 wires ( http://i.snag.gy/wlSX0.jpg ). The webcam has 5, and the digitizer uses 6, so I guess that would leave enough room for the 2nd lane? I'll have to open it again tomorrow to confirm the wire number on the motherboard side.

As for the MB itself, it turns out to be a Quanta ZHK, not Compal. But unfortunately I haven't had much luck finding schematics for it, with all results on google leading me to sites that demanded I pay for the download. :/

 

If anything, think there'll be more than 5 spare pins on the mb side. Mb people like to join voltage and grounds (to simplify/save room), whereas lcd people take the safer approach and want more connections (to divvy up the load).

And motherboard's quite old then (they've long since ditched Quanta for Compal).

Fortunately, the wires are coloured; easy to match to motherboard connector. It will still be a bit of a gamble and from that image it doesn't match the B116XTN01.0 at all (pdf available). Hunting or buying the N116HSE-EJ1 would be the surest option, but can also pull back more of the black tape surrounding the connector on the lcd's pcb and look on its back if you can access it; the "R" = Resistor and "C" = Capacitor, but the actual data and clock pins will be labelled as well; track and pen these down. At least it'll be possible to verify whether replacement cable xyz has wires located on the pins in use.

For next time ... consider buying a Clevo; they have schematics readily available, much easier. This is a 30-pin/4-lane eDP:

Search for the 'AUX'/'TX'-type labels on the mb's pcb. Also, there'll be a minimum of three free pins side-by-side if 2nd lane exists.

 

I was finally able to find schematics for this motherboard on a Chinese site, and although it's for a different revision (docs say 1A and my laptop has rev. C) I doubt there are any differences between the two in this matter:

So the conclusion would be that it's not possible to do this upgrade for this laptop, since not only are all but one of the 30 pins on the mobo connector used, but the first lane is actually the only one traced from the chip. Oh well...

Thank you for guiding me to a conclusion.

 

That deduction, Sir, is excellent . Shame about the result ...

However ... if you want; solder two wires to TXP_1 and TXN_1 (include tiny capacitors) and hook the other end to the proper pin of the display's connector. Thus bypassing the mb connector altogether, which is, after all, only a convenient 'gathering place'. No need for schematic; pcb of the display will be labelled. Currently, the 1-lane uses an smd-type capacitor, but it's easier to use one with leads (this would work: UK10-104).

Fortunately, the onboard gpu supports 2560x1600, so not only the 2nd, but even the 3th and 4th lane are operational. They only lack somewhere for the signal to go to.

The alternative is another new screen, except a 1-lane this time. Upgrade options are rather limited, though ... 768p panels are a bit ' every-$0.01-saved-is-an-improvement'-type of product. There are two exceptions, but these are 8-bit colour (like your current fhd) and this requires 2-lane (again).

 

I've also thought about wiring the other lanes directly, but as the gfx is on-chip, that's where those pins are as well, on the soldered-to-the-motherboard CPU:

(not *my* mobo, but a better quality picture)

As for getting a different panel, it's not really something I'm considering. Given the current usage pattern, I can live with this one, but it would've made a fun DIY project to replace it with the 1080p one I received.

 

True, but they might still lead somewhere away from the bga, only to be terminated elsewhere. Many boards are re-used in different laptops, only selectively disabling certain bits/functions. This example too, maybe a dedicated audio card or something ... anyway, the solder blobs are powered/connected all the same. Cheaper that way; make a single motherboard and leave out only the relatively expensive components.

Only problem with this type of laptop is that the pcb is hardly labelled, making it quite difficult to find the TXs (you'd look for the capacitors C6* and trace back). Probably wasn't deemed valuable enough to be repaired, only a remove/replace type of service ... kinda sad. Maybe trace back from the lcd connector?

Btw, that thing in the red circle ... noticed these before on very modern/recent systems. Thing is ... looks like it was designed in the 90s, wonder what it does ...

 

That's the ethernet magnetic transformer. My board has this one.

As for the pins actually being traced to somewhere, along with the diagrams I snapshotted above there was also a board view up on that site, but the couple of apps I tried to open it with (kicad and eagle) failed with 'unknown format'. I've yet to try the Allegro viewer, hopefully that will help me get a definitive answer, as it's supposedly for the exact revision in my laptop.

 

Interesting, thanks . Had to look that up:
Why Are Ethernet/RJ45 Sockets Magnetically Coupled?

Good luck with the mod, would be great if you can make that work. That stock panel is really ... ghastly.

 

The final nail in the coffin:



The weird oval thingie I drew surrounds the 2nd lane pins, and there's nothing there (and to its right are the other lanes, also unconnected). So this is really where the story ends, as reballing a BGA to wire out those pins is way over my league, and I'm not really willing to invest $$ in this, to have someone else do it.

As for the empty slots you highlighted above, the one near the RAM connector is where the TPM chip should be, and the other shall forever remain a mistery. It's not there on my board, and I'm not noticing anything similar either.

Thanks again for your help!

 

Too bad . Reball (~$50-75) would be tricky anyway; not much room for a coated wire to wriggle in-between. Would be pretty hard-core, though .

Not one to give up; HDMI control board for 11.6" N116HSE EJ1.

Drawbacks:

1. Size; might fit inside a DTR, but certainly not in an 11.6".
2. Power; needs 12V, thus either a separate adapter or tap directly into the battery. If that actually does 11.1V ... most do, but maybe not these netbook thingies ... the '4A' is too excessive, probably max. only.

Could make it an external monitor, though (or a tiny TV).