Saturday, February 12, 2011

DV5-1124 Motherboard replaces -1125

Insistent Customers and Laptop Repairs -Arrrrg!!!
What I had to do to get  a laptop back to the customer before factory heat-sink is replaced.


DV5-1124 motherboard without heat-sink
This customer was without their laptop for a couple of weeks [from another shop] waiting on the correct motherboard  to arrive. When the new motherboard arrived, it did not come with video memory management unit (mmu) heat-sink. After running a few minutes, the mmu would overheat and the unit would shutdown to protect the chip. An irate customer could not do without for another 3-5 days waiting on the factory heat-sink. So a minor custom heat sink was made to 'hold-off' the customer until it arrived.


It consists of a copper pad, plastic sheeting (on underside of pad) with a cut out hole. The copper bridge soldered to the pad was to act as a heat bridge to transfer heat to the original heat-sink.  This is not a recommended repair, only a temporary fix.  There were no guarantees presented with this method, and only allowed the customer time to use the important files until the correct part arrived.  There were no temperature measurements taken after the 'fix' only run-tests. 


DV5-1124 motherboard with
temporary heat-sink
Previously the unit would run about 2 minutes before shutting down due to heat. After the 'fix' the unit was stable enough to run without shutting down. So problem solved* until replacement arrived.


With the various model numbers of the DV5 series, it is wise to pay attention to the dash numbers of motherboard replacements. DV5-xxxx - 


In this case: the original board was DV5-1125 and replaced with DV5-1124.  The minor difference in the model number had larger implications. The original used shared video memory and the replacement uses on-board memory. Though more ram memory available is for Windows/applications/programs, an additional part (MMU heat-sink) was needed.  I hate to do mods but had to in this case.


Note: plastic sheeting with cut-out for MMU ceramic was done because the chip has resistors on top, if there was no insulation it would present an opportunity for the copper pad to short the resistors,If laptop grabbed from bottom or picked up in an unusual manner. This would either blow the MMU chip, or cause improper memory addressing, depending on what section is shorted.  MMU heat is transferred across bridge to larger mass of the main heat-sink. Engineering students may need to know thermal dynamics well to understand how heat travels.

Note: High Temperature hot glue was used on corners to hold copper pad to chip after thermal compound was applied to copper pad. The glue is easily removable when cooled, without pulling parts from motherboard.


Note: The 2cm rubber blocks were used to press the copper pad down when reassembled into case.

Shift-click (Shift-Tick) to see larger images without being redirected.


Do Not Copy this method since it is a temporary repair!~

6 comments:

  1. You and I seem to run into similar problems at the same time. This is too funny. I have a DV3 that I ordered a replacement board for and I too didn't pay too much attention to the part number of the board. Like yours, this new DV3 board had an extra chip on it near the GPU that needed to be cooled. Nice mod though! I'll be performing something similar in the next couple days. Whats even funnier is this customer too is dying without her laptop. Isn't dealing with the public fun?

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  2. MattBrad: I know the feeling. That is the primary reason I'm doing the blog. We have so many techs out there that find a solution that others are experiencing yet none of the 'tips' get out. So you have tech's in every corner of the country each having to discover a way around issues.

    Customers not realizing some of the problems only make the job more difficult. After all it's not a waterpump being replaced on a car. It is a COMPUTER device! More sensitive, smaller and more finicky than a car.

    Take it easy on us when you think it is taking too long. If they are especially mean or rude, I'll give it back to them and do DC Jacks to calm my nerves. After all no one can accurately tell what problems we can run into before opening it up.

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  3. Agreed. If I hear "I'm sure its something simple" one more time...

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  4. "I'm sure its something simple", usually its "i cant do without Facebook"

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  5. Hp part numbers are always formatted 000000-001, 0s being numbers the 001 mostly staying the same sometimes changing to 031, it's the only way to ensure compatability, most boards the pArt number is under the memory while others like the dv2000 on a sticker elsewhere on the board

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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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