Acer aspire 7520 no video

[primoz1]

Hi. I got this laptop, and turn on OK: work fine on external monitor, but on primary lcd just show logo and no light after 1-2 sec picture disappears.

see video on this LINK

I do reball the MCP67MV-A2 chip, and no changes. Maybe inverter is broken too, so I ask here, how can I test this inverter ?

Thank you.

[primoz1]

Re: Acer aspire 7520 no video -fixed-

I fix this issue. LCD screen bulb is bad, I change panel and now work OK. In occasion I will ordered a new lamp with eBay and save old panel.

[ratdude747]

Re: Acer aspire 7520 no video

for future reference, A tip for troubleshooting:

use a flashlight and shine it on the screen if and when it goes blank... if you have a backlight or inverter issue, you will be able to see what is supposed to be displayed. if you get nothing, it isn't the backlights or the inverter.

[primoz1]

Re: Acer aspire 7520 no video

Thanks for this info.

Now I got new problem, I install windows 7 and xp pro, and audio non work, in win 7 is no device, in win xp the device is there but sound no. Maybe must reball MCP67MV-A2 again. Is possible to this chip cause this error ?

Thankyou.

[tschanuka]

Re: Acer aspire 7520 no video

primoz1:

If not a driver issue (onboard HD-Audio sometimes not recognized correctly trough Win and incompatible drivers are installed), then mcp67 could be the problem, yes.
The chip manages the function of the audio codec chip.

Btw: Reballing this chip will not last long in most cases. Better to change for new (hard to find original at the moment).

[primoz1]

Re: Acer aspire 7520 no video

I lift this chip again, but after detail motherboard incpection, I found 5 missing pads on motherboard under MCP67MV-A2 chip, probably the first time I was not so precise and I missed this 5 pads.

So I search defective motherboard, but on eBay is too expensive even defective. 29$ for board and 18.47 usd for shippibg cost is way from reality for defected board.

[tschanuka]

Re: Acer aspire 7520 no video

Missing Pads could be repaired, but it´s a not an easy job to do.

Some pads under the chip are not used (empty, no signal). You could post a detailed picture with cleaned pads so we could check that and tell you if or which pad(s) of the 5 are needed.

[primoz1]

Re: Acer aspire 7520 no video

Hi.
Unfortunately, the motherboard has returned to the owner. And I did not make any picture of missing pads.

But, I am still interested how it can be corrected this pads ?

Thankyou.

[RJARRRPCGP]

Re: Acer aspire 7520 no video

the device is there but sound no.

I seen this problem before, with Vista and maybe 7, with RealTek audio, IIRC, because of a bad sound driver version.
Apparently bugged to hell and with another sound driver software build I got, which was downloaded, it was fine.

It looks like the driver that Vista comes with (maybe 7, too) is broken. Windows, IIRC, reports zero problems, but I hear nothing!

[tschanuka]

Re: Acer aspire 7520 no video

@primoz1:

I try to explain in theory how i did it in the past:
Missing pads will be replaced by a thing wire (0,1mm fly line).
You search for next possible contact (or make one by scratching the pcb) of the data line (by schematic, sight or multimeter in diode mode) and solder one side to this contact and the other end of the wire will replace the missing pad. That end can be bend in circle or something. Depends on the size of pads and thickness of the wire. The wire could also be fixed with some epoxid or kapton tape.
There are other techniques and even professional bga pad repair kits but I don´t know how good they are and above method worked for me.
You could rip off pads of a dead board and try to fix some to find you own best way to do it.

But I highly recommend to optimize your bga replacing method. Maybe it is just a small thing like wrong flux, wrong temperature or time of the bga profile, wrong solder iron/tip ...or maybe a bad station and so on. There should be not only profiles (or manual changes) for lead and lead-free but also for different type of boards, sizes of bga chips and epoxid.
If you really work on optimizing your techniques and tools there will be very rarely something like pads ripped of.