Tuesday, October 26, 2010

Gateway MD2641U - USB and Shutdown Problems

Gateway USB ports not read -


This Gateway MD2614U would not recognize the USB ports or devices plugged into the unit. The problem was found to be manufacturer packaging mistake.  Unit made by ACER in Taiwan has a large plastic cover on bottom of motherboard, but the surface mount resistors coils, and capacitors were not wave soldered well, so the bonds were not sticking to mobo, instead to the adhesive on the plastic. About 12-15 SMT parts were stuck to the plastic and had to be manually placed on the motherboard in their correct location for the USB ports to be read.


The original reason this unit arrived was black screen/no video. Similar to the problem with the DV series using nVidia GPU though this was an ATI Chipset, the Southbridge and GPU were reflowed to assure solderballs were connecting under the chip itself.


How did I find out this issue?  Near the USB connectors the resistors were identified by their circuit designation, in this case it was the 300 series. (R353, C323, L341 etc) so checking under the plastic many of the parts were from this circuit. (see closeup as example)


The size of these parts are about 4 sugar crystals in a square pattern.


One part at a time was removed, folding the plastic toward board to see where it came from, then removed and one lead was soldered with needle point iron. After all the parts were placed on the motherboard, flux was added to the area and the other lead was soldered.  After both sides of parts were soldered, the whole area was reflowed with low setting on heat gun.  This was done to center parts on pads and to evenly flow the solder, and to help reflow any additional parts that may had only one pad connecting and  not visible to magnification. Also it is the recommended 
repair process to correct solder defects. (corrected solder
is shown in the lower picture)


Scotch tape was placed over the adhesive to keep additional parts from sticking again-notably the parts in the 200 & 300 series circuits. (The 200 series parts were used for the card reader to left)


To remove the parts from the adhesive, the tweezers were slightly heated to make it easier for the release from the sticky bottom. Be careful not to grip the parts too firm because they will fly from the tweezers and very difficult to find!


Good Luck!


Note: I've gotten another of the same model with different issues, this solution will be posted when opened.

17 comments:

  1. Welcome back. :) I was worried you weren't going to post again. Great find! I don't have the guts to attempt work on such small parts.

    B-TECH Computer Repair

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  2. Yes, welcome back. Good post! I have an eMachine E627-5012 which is very similar, I think, with USB detection problems. User mangled the ports and I replaced them but the laptop won't detect devices plugged into the new ports. I'll look for similar damage.

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  3. thinks good observation a have solution for dead dv5

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  4. Well, the eMachine E627 wasn't as similar as I thought. The black plastic protection sheet was bonded very strongly to the motherboard and I would have had to destroy it to lift it, which I wasn't prepared to do. However, it's a great tip for the future.

    BTW, any idea where to find replacement USB ports? Digi-Key and Mouser don't have any for laptop motherboards, that I can see.

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  5. Larry: Since I cannot fix absolutely everything, I usually wind up with spare parts boards. First I learn who made it, then look on the other boards generally in the same processor class/age range. Like I happened to discover that this particular machine was made by ACER so I looked on those first.

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  6. If you need to pull the plastic back, you could warm up the plastic (with heatgun on low) and ease it back, but make sure parts are under it first so you don't waste any time, and Pull slowly.

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  7. Fixed! The problem was that the connectors I installed were Type A whereas the originals were Type B. The result was that the device pins were inverted, so that pins 1 and 4 are reversed. I learn something new every day!

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  8. Whoops, I misspoke. What I should have said was that the original connector had the pins facing up but the replacement had the pins facing down, not that one was Type A and the other Type B. The end result was specified correctly, i.e., that the device would have the connections reversed. because I used the wrong connector type.

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  9. Where in Charlotte are you located? I am in Spartanburg, SC. I would love to stop by and see your shop one day. I get to Charlotte about every other month,

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  10. Brian, I can't take the credit for figuring it out. It was a friend and colleague who asked if I had the right connector and reminded me that they come in two versions.

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  11. B-Tech: Email me for the address. Since I am heads down most of the day solving logic problems. I dare not to post the address worldwide. I'd hate to have a steady stream of people wanting to see me work. I wouldn't get anything done.

    LarryS: Good find, you have to watch those USB ports, some are upside down, some are over-under some are side by side. Thats why I keep dead boards, you never know when one is gonna come up that you need parts from.

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  12. Mayo,

    I have a question about how the maxim 8734a functions. I've tested the v+ line and it shows 19v which is what is coming out of power adpater. However when I test the linear regulator output, LD05 it is only putting out .7v (as well vcc). Is this chip bad or is there something else needed to get the linear regulator going? I tested OUT5 and it does not test at 5v which is what is required to bootstrap the smps and shutoff the linear regulator. The background on this e1505 motherboard is that the owner's dog chewed on the power cord, and ended up damaging the power brick. Swapping out the power brick didn't fix anything, but when I plug in the battery the battery led flashes orange. Thanks again for your help.

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  13. Also do you know where I can order the max8734? I've looked on ebay but most of their stuff is from Hong Kong. Anybody you know sell this from the USA?

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  14. Ulises: on the e1505, I try to report repairs I find, and not delve into others troubleshooting, since that would be nearly impossible in a blog. And afterall I think the it is quad output supply. So you may have NEG and POS voltages exiting the MAX8734. When trying to save time, you may have better success swapping parts faster than extensive point-point testing.

    Also you may try to get 'samples' directly from MAXIM http://www.maixm-ic.com they are pretty helpful with the devices they make. Though going into the technical specifications via email you may not have much luck since you should be well versed on the functions of the products that you are troubleshooting. Also check with Digikey for componenets.

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  15. Hi there, i have a Gateway MD2614u, it doesn't power up. If i let the battery in the laptop, the battery led will turn red. I tried to remove RAM, BIOS battery and nothing.
    I pressed the power button for 30 seconds or longer without batttery or AC power, the tried to turn on but nothing.
    Any idea? Do you think you can help me? Thanks!

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    Replies
    1. That model is a lemon. Check under the plastic.

      It has so many issues there is no sure way I could identify what are wrong with them. This post was the only one that I fixed out of 3.

      Delete

I cannot repair laptops for you via the internet, I can only answer questions related to posts. This is because I have not had experience on every motherboard that is out there. Bear with me.

If you do need it repaired. Contact me for quote (US/CDN Only)

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