Acer Aspire 3 Q5WV1 ic Chip compatability

[garrymc123]

Hi There

I have this laptop in for repair and ic chip q19 is corroded but the only place I can source it from is china which is obviously not an option just now..is there any other chip that is compatible with this that I can source within the Uk.

Thanks in advance

[SMDFlea]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Just google search the part number "DMN66D0LDW-7" ,they have them at digikey ,mouser,rs-online


https://uk.rs-online.com/web/p/mosfets/7514212/ 25 for £2.30 inc VAT + Free delivery.

.

[garrymc123]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Thanks, smdflea that's them ordered..

[garrymc123]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Hi Guys replaced ic chip and now have 5v back fan spin and display but the screen is red and flickering but can still see the text so I checked the lvds connector and there was some mould or something on the pins I cleaned it the best I could and checked for bridges but none their even checked with a microscope but the screen still red i marked the affected pins in the schematic. i also checked with another compatible screen still the same and changed the connector still the same so checked the screen on another laptop and was fine. so my question is what can I measure to see if I can find a problem I have 19v on the first 3 pins and can you buy the motherboard lvds connector if I need to replace it.

Thanks in advance

[emestee]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

so my question is what can I measure to see if I can find a problem I have 19v on the first 3 pins and can you buy the motherboard lvds connector if I need to replace it.

Thanks in advance

Test the lvds pairs for resistance. You might find one that's not like the others.

[garrymc123]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Thanks, emestee for your reply have you any idea roughly what they should be .

[emestee]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Thanks, emestee for your reply have you any idea roughly what they should be .

Depends on the platform, but the lvds pairs should be similar with each other. Low ohm range would be indicative of a fault. OL would be indicative of physical damage. You're testing for anomalities, not certainties.

[garrymc123]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability (display problem now )

Hi there I have taken measurements from a working laptop same model and I have noticed two differences which are

pin 13 on working laptop its 1.37v on red screen it's 0.9v

but the biggest one I noticed is pin 24 working laptop its 0v red screen laptop its 1.2v all the rest which go to ground are 0v

Any idea where to check guys I have double-checked the connecter and it looks ok no bridges between those pins

any help much appreciated

[emestee]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability (display problem now )

Hi there I have taken measurements from a working laptop same model and I have noticed two differences which are

pin 13 on working laptop its 1.37v on red screen it's 0.9v

You are not taking the measurements correctly. Voltages can and should be measured on power rails and signal lines that are either very slow or are in a steady state. You are however measuring LVDS lines, which are high speed differential signals. The results you get from measuring their voltage against ground are meaningless. The multimeter will show you either some voltage over its sampling period (plus measurement noice), or a steady voltage if the line fails and outputs constant voltage level. You won't be able to tell which is which.

First, the LVDS signals come in pairs. You should be measuring the resistance to ground in each signal to detect shorts to ground, but more importantly, you should be measuring the resistance between each signal in a pair. This is because chips that use differential signalling have buffering components that encode streams of data into pairs. These components are electrically closest to the signal lines. If there is an electrical fault, it is most likely to be there.

If you want to measure electric signal levels in a LVDS line or the presence of data exchange, use an oscilloscope with an X10 probe.

More importantly, be very careful when measuring LVDS signals because the low pitch connectors are very easy to short with your probe and you definitely do not want to accidentally send a power rail into a signal line. Never connect or disconnect laptop keyboard and matrix connectors while the power is on or the battery is attached. You will kill something.

but the biggest one I noticed is pin 24 working laptop its 0v red screen laptop its 1.2v all the rest which go to ground are 0v

Unfortunately, you may be onto something. For this to happen there must be some physical damage to the connector or to the components on either end of the cable. There can not be voltage on pin 24 unless that pin is not actually connected to the ground. The problem is, you can not pull out the cable to test - because if you pull out the cable while the power is off, the matrix controller will not detect the matrix and may not power up LVDS exchange, i.e. absence of voltage will not indicate that there is or isn't a problem. If you pull it out while the power is on, you risk damaging the matrix. However, you can supplement your measurements by opening the matrix panel and testing the same on the other end of the cable.

You should also examine the soldering of the connector under a looking glass or a microscope. If it is one of the connectors whose pins are under its body, there is no way to check it without desoldering the connector, which requires skill. However, it does happen. There can be corrosion or solder bridges hiding under the connector.

[bachir2004]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

have you tried another screen?

[garrymc123]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

Thanks for your advice on this one I didn't want to try and do the tests on the lines in pairs as I've not got the steadiest of hands and probably short out something but appreciate all the information you have given me. I have checked all the pins with a microscope and can't see any bridges unless it's inside the connector was going to check resistors or caps on the line but it goes straight into the pch I have tried the screen in another exact same laptop and it's fine including the cable, so my next step is to replace the connector is there anywhere where I can purchase the connector.

Thanks

[SMDFlea]

Re: Acer Aspire 3 Q5WV1 ic Chip compatability

There`s some for sale on aliexpress, or just buy a spares repair board on ebay.

https://www.aliexpress.com/item/1000001921470.html
https://www.aliexpress.com/item/32517986250.html