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Showing posts from 2010

Gateway MD2641U - USB and Shutdown Problems

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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, C3

More updates coming

Having been busy has kept me from updating regularly. Now it's just a time management thing. So further updates will be forthcoming. This weekend is a long weekend in the U.S. hopefully I can post more repairs. Compliments with an ad, is still SPAM I would like to ask readers not to post Spam links unrelated. But if you have a post on how to fix something feel free to post. I don't think many readers do not want Generic Viagra, Retirement Home in Costa Rica or discount batteries in France.  So don't be a Blog Troll posting advertising.  That is annoying, and I'm sure you would not like me to make an issue of that. Because it will make me require membership, and confirmation emails before you can post. That effectively reduces communication and answers that many people are looking for.

Acer 5516 - Dead, No Power, No Lights

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Finally a breather before the storm came. (Load of work) This jack was damaged by drop and or push. The lead broke/shattered as if it was hit while running. Copper can shatter too, you know. This should be clear enough LarryS.

Acer 5515 Works off Battery, Charges, but will not run off AC

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This unit arrived working from a charged battery, but will not power on from AC.  My first thought was bad leg on the DC Jack, Easy job! Finally Upon opening the case and removing the keyboard I saw the beginning of the failure. Burnt MOSFET under the keyboard directly behind the battery connector. So took the rest of the panels off to see how bad it was. Out of a scale of 1-10 with 10 being the most difficult I rate this as a 7.5 because it was more annoying than difficult. The copper under the MOSFET was actually welded to the legs of the FET, heating solder would not break the weld. Click to see larger image The visual shows almost the worse case scenario for a shorted MOSFET. Burnt and totally unreadable numbers.  Seeing the circuit I surmised that it was an identical pair of chips but I had to verify against another motherboard to be sure.  Also there was a scorch mark under the keyboard, but it didn't affect the keyboard or any keys.

Compaq 6735b - Dead No Lights

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This was a strange cookie.  This unit showed no sign of life and was a weird design for power in button.  I have to admit this was a 'lucky' repair. While diagnosing where was the DC power, I discovered that a power MOSFET was open, No Power anywhere, no lights, no charge and stone cold dead. On the bottom of the board it was a mosfet FDS6676 that was open.  When I replaced it with a substitute I was able to follow the DC circuit, but it dropped off at the power button. So testing that area I noticed that when I put the meter positive on point on the board the light behind the pwr button would flash briefly. Recalling a similar experience where I had to modify another CPQ 6735 when they first came out/released. I thought I would try my luck again.  1: With the meter set to VOLTAGE and holding the meter's positive lead on this point, the unit would come on. My first guess was 47k Ohm. This worked but the laptop would not turn off, or would come on when it wanted

DV6000/DV9000 Lines in LCD and External monitor -unreadable

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A fairly common problem with this series is lines in the LCD and external monitor. Sometimes it will exhibit scrambled characters on the screen. Similar issue.  This is because the video memory has fail or lost connection and the addresses cannot be read properly by the system. The rest of the system may work but video is not proper and screen unreadable. Lines and streaks on POST screen Should show BIOS info and CPU info            This shows the step by step on how to correct this problem. There are other videos on YouTube dealing with the 'no-video' issue. Some are dangerous, others are goofy. I will be getting back to that production.  Not wanting to knock anyone for trying, but be careful, some of these guys are not techs or engineers and have no clue of consequences. 

Laptop Rebooting- DV6000, F700

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While working on a DV6000 today I decided I should also address other problems with these models while working on the DVD production.  As it seems this problem is also quite common, Rebooting, looping, restarting.  Never getting to the Windows startup screen. OK there are several causes of this scenario with the ribbon cable being shorted or defective.  The ends of the ribbon cable can lift away from the surface when inserted and shorting the lead from the adjacent wire.  Some times it will short and cause the wire to burn. Other times it will cause the REBOOT/LOOP issue.   Also verify that the Coin Sized CMOS battery has 2.5v- 3v, if not or voltage is low, all kinds of problems may present themselves.  Correct operating voltage is needed to read the CMOS data, or the data may be corrupt or deleted. How to test/bypass these? 1: Disconnect the PWR connector cable, and turn the system on with the remote control (if you have one).  Make sure the battery is good in the remote

Format Change and Redirection??

Considering going to FORUM Format, this way dialog and content can be better grouped and followed.  This will stay up and be mostly for posts, but the forum will be best served for post and pictures that need to be answered.  The Blog only allows pictures at the beginning, and questions afterwards cannot post pictures.  Keep in mind this is intended for Technicians, and experienced individuals.  There is no way that I can train via the internet on how to do something. (At least not in the current format) Since I see that there are lot of others that have been left behind, and some schools are not finishing the job.  I will try to outline and classify better on the new Domain.  You will have to subscribe so that I can at least keep track of my mail, questions and answers. One thing I do ask, is Try to STAY on blog, direct questions to my email address misses hundreds of others that may want to ask the same thing, or are asking the same thing.  With so much time answering and 't

Writers Block? Nahhh

Due to activity and being summer I had held off posting some items that had come across my desk.  So shortly expect a flurry of activity. A recent email asked several questions that I think I can answer before hitting the grind again. Do I do my own reballing? No, the method I use corrects the solder balls. The biggest defect of BGA and RoHS solder is tempetature and contraction of metal. Down on the atomic level, the valance bonds of the multiple elements used (in solder) break and you get a weak composition. Excessive heat causes metal to retract to themselves. So instead of getting a bond, you get contact.  Example: In the DV series, the breakdown is as follows.  After a period of time and use, the vents on the heatsink will become blocked.  This is from typical use and the placement of the Air In slots on bottom. They draw in fibers from pants, shirts, sheets, bedding, pet and human dander and carpet. Often larger than the vents exit. As more and more collects the vents beco

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IBM Thinkpads No video, No P.O.S.T. Models T40, T41, T42

Advanced Notice:  I will be detailing the method on how to fix Thinkpads - No video No POST issue. This is a quite common problem with the T-Series. 1: The system lights up but nothing shows up on the LCD 2: Nothing shows up on an external monitor 3: Hard Drive does not initialize. What makes my method so much better? You do not have to totally disassemble the whole laptop  (a major time killer). Only need to remove keyboard, and wrist rest. You will not misplace screws and use the wrong screw holes! Following directions it will work the first time! So if you don't have the readily available items here is a brief list to get them ahead of time. Heat gun , similar to those used to heat shrink insulation on wires.    At least 500 watts I got mine at Harbor Freight  and used on LOW Radio Shack Paste Flux $6.99 (mentioned in another section of this blog) Two pieces of thick aluminum foil 4" x 4" (10cmx10cm) .     This it to make a heat mask so the plasti

What is causing the DV Series to fail prematurely?

I have seen dozens of 'solutions' and fixes for the DV series and none really address the root causes. Others damage or ruin motherboard. Below are some of the weirdest solutions I have seen: 1: Placing a penny between GPU and Heatsink. 2: Using a copper shim (only slightly larger in area than penny) 3: Excessive thermal compound 4: Wrong type of compound. 5: Placing a tea candle (in aluminum holder) on GPU 6: Putting Motherboard in oven 7: Pressing down on GPU real hard 8: Reflowing without flux?! Outline what each does and why it still fails later. 1: This will increase the pressure on the GPU when held down with 5 screws, a temporary solution, but does not remedy. Provides no greater heat dispersal and only transfers heat through penny. Metal fatique may damage the 5th retainer screw and not support the GPU. 2: Copper shim does the same as above. 3: Spreads heat over a larger area but does little to cool. 4: Does nothing 5: Can accidently cause more damag

DV9000 Overheating

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A DV9208 arrived with overheating problems. Luckily it was caught before it started generating additional issues with the GPU. Symptoms: Unit would overheat, cause shutdown/off without notice. WIFI would turn off Cause: Heat sink vents 75% blocked, so insufficient cooling was the culprit. Repair: Disassemble unit, disassemble heat sink, clear vents. Problem #2 was a little more different. Because the Southbridge would also overheat, causing loss of contact on solderballs. Solution: Clearing the lint from heatsink will remedy issue with overheating/shutdown. Since no drive arrived with unit a substitute drive was used to run system for several hours, then turned off, and test again.  I do this about 4 tests so that nothing happens when it gets back to the customer. Aluminum heat transfer pad for CPU replaced with copper pad.  The pad from HP is only ok, but many times the CPU gets so hot that the Aluminum breaks down and sticks to the CPU. Not providing a good thermal 

Back from vacation

Since I was out and about, all the time reading news, features and other tidbits from technologists, I decided I would make some observations. Hype vs USE iPad and the real world. Sad to say this unit does not live up to the hype. It is small lightweight and does view the web, but the bad points exceed the good for PC users to jump on the bandwagon GUNG-Ho. 1: The lack of USB on the unit requires additional costs. 2: Using 3G is out of the question unless you pay more. If you have a 4G service such as Clear.Net you cannot even use it. Why? Because it is an x86 install and USB dongle. 3: The entertainment use is out of the question . It cannot view YouTube Videos (which uses Flash Video format -FLV) You cannot use NetFlix (which uses MS Silverlight), and No HULU (again FLV). So that means you cannot do much. Not even view ABC/NBC/CNN/CBS News sources . Such as the tornado pictures from Oklahoma.  Corrections: It seems that some sites are changing their whole direction and hav

Important parts on DV6000 and DV9000 series

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These are important parts if you are looking for shorts or opens on the DV series. This image shows the location of the FDS6679. A common cause of shorts in the DV series. When the power supply is plugged into the laptop and it shorts out/turns off it's usually caused by this MOSFET being shorted.  Plainly stated. You plug the adapter into the DC Jack and the Blue Ring fails to light up, and the Power Supply shuts off. Giving no power to the tip. To reset adapter, unplug from AC (mains) and wait 15-30 sec. Then plug in again. The adapter is not damaged, since this is how it is protected. These parts do not determine charge time or per centage. The FDS6679 only closes to complete Positive circuit.  The AO4407 only closes when the battery is plugged in. As a test- Check the voltage of the Drain side (pins 5-8) with AC adapter and no battery - you should see 0 volts.  When you contect the battery you should have 10-14v depending on DV6000 or DV9000 series. IF the AO4407 is open

My Review of 2 oz. Non-Spill Rosin Soldering Paste Flux

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Originally submitted at RadioShack This electronic-quality rosin soldering flux is mixed with petroleum jelly and ideal for electrical and electronic soldering applications. 2 oz. Non-Spill Rosin Soldering Paste Flux Actually the best available By TheLaptopDoctor from Charlotte, NC on 2/19/2010   5 out of 5 Pros: Good heat control, High quality, Deoxidizing Cons: No liquid version Best Uses: Large Projects, Minor Projects Describe Yourself: Professional It does the job exceptionally well. As a NASA/MILSPEC/AF soldering pro this is currently the best product available retail. Though wishing they had a liquid version available with needle dropper. I heat mine before using a dropper to have it in a liquid state for better flow control. When it has to be exact Tags: results using product ( legalese )

HP DV1000 - Dim LCD

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This was a challenging dog of a repair , but after too many hours I had to give it up. Items checked, replaced or repaired. LCD cable - replaced LCD connector - replace and repaired Invertor - checked backlight - checked LCD - checked Lid Switch - checked The LCD was first checked with a known complete lid from another DV1000, the unit still showed same result. So backing up checked the LCD connector first. noticed connector had internal damage -replaced (same problem) noticed motherboard pin 29 was also blown off motherboard - repaired (same problem) lid switch check for open/close continuity - passed backlight - passed The conclusion is that that motherboard damage was greater than initially reported or known. Previous tech had made some minor mistakes, but nothing serious.