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  Hp dv7-1245dx memory problems 
 
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Laptop Willie Mar 31, 2011, 07:05pm EDT Reply - Quote - Report Abuse
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>> Re: Hp dv7-1245dx memory problems
john albrich said:

Would I be correct in assuming you've already examined under magnification the connector pins for shorts, cold joints, and improperly flowed joints (e.g. convex v. concave)? However, I'd also make sure to examine the memory interface/controller chip connections as well.

And of course inspecting for missing/wrong-value noise suppression components (resistors/capacitors) on the signal lines. I've seen production runs where the wrong parts were fed into the belt feeders and line diagnostics did not sufficiently deeply test the boards. The part error was found only when a line tech noticed the mis-loaded feeder after hundreds of boards had been populated.

Also, have you electrically tested for internal shorts across the connectors?

One might also consider applying a sharp point tool to each solder connection and deforming the solder a bit (e.g. putting a small "crater" in the connection). This has the potential effect of mechanically deforming any poorly flowed or cold-joint solder connection, and can result in temporarily "fixing" a problem...much like the guitar-pick "fix". Of course over time the "fix" will likely fail again due to on-going temperature and mechanical fluctuations. But...the point is it can reveal visually hidden poor connections and one can then focus on that aspect.

If HP had a manufacturing quality problem, it could have existed for some time before field reports came in and they addressed the problem. That could have led to a relatively long production run of marginal/failed units. Thousands of boards could be marginal and in the field.

John, I'm a fan of yours. You seem to always add quality input to these posts. I do examine using 10x and 15x powers. Just haven't found anything yet.

I am sure that HP had problems with the whole Entertainment line of laptops. All the DV series. As the the lines between the connectors I have checked those. I'm not sure which is the controller chip you refer to. Is there a way I can determine which chip this is.
I too have worked in the manufacturing side repairing the failed boards from production. But, we had layouts and schematics for the boards.

Laptop Willie
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john albrich Mar 31, 2011, 08:11pm EDT Reply - Quote - Report Abuse
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>> Re: Hp dv7-1245dx memory problems

Unfortunately it can vary depending on the age of the computer and the CPU series involved. Some CPUs include the actual memory controller on the CPU die but still have external memory interface support chips between the CPU and DRAM. E.G. to level shift signal voltages, how they architect sharing the memory bus, etc. A recent example would be Intel's SandyBridge where Northbridge is integrated into the CPU module. In older Intel systems the Northbridge chipsets may be ID'd in drawings as the "Memory Controller Hub" or the "Integrated Memory Controller".

If the motherboard uses an external Northbridge chipset I'd definitely check at least the primary module. It's usually not too difficult to ID the main Northbridge module as it's one of the larger modules and often has a heatsink...however it's not always heatsinked. It's likely too difficult to identify additional memory-specific support hardware without a schematic.

http://www.maxim-ic.com/solutions/desktop_computers_motherboar...iagram.mvp
http://www.vaughns-1-pagers.com/computer/pc-block-diagram.htm
http://en.wikipedia.org/wiki/File:Motherboard_diagram.svg

Laptop Willie Mar 31, 2011, 08:49pm EDT Reply - Quote - Report Abuse
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>> Re: Hp dv7-1245dx memory problems
John, do the diagrams hold true for the dual core CPUs?

Laptop Willie
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Laptop Willie Apr 03, 2011, 07:00pm EDT Reply - Quote - Report Abuse
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>> Re: Hp dv7-1245dx memory problems
After all the head scratching and swearing at this thing, turns out the CPU failed. Thanks to all of you for your suggestions and help. :)

kieranosaurusrex, you are my hero. It would have been going earlier had I ordered the correct CPU. :)

John, thanks for the help with the diagrams. I do understand them. It has just been like 20 years since I've looked at them.:)

This is the first time I've ever had a CPU work half-a** before. I've had them fail completely or work well. Over 20 years in this business and I'm still learning. :/

Anyway Thanks Guys.

Laptop Willie
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