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LGPA 775 & Mobo Failure Options

By older **** ·
I have a HP M1270N Media Center PC with a Puffer M-UL8E [proprietary ASUS PTGD1-LA] mobo. It ran flawlessly for about 1-2 yrs. Then it started acting up with various black screen Windows Boot "config sys" error messages, and finally failed with no POST/Video/boot at all. Only the PS/fans came on.. After T/S for obvious PwrSupply/Video Card/etc issues, I tried replacing the P4 LGPA-775 3.0GHz processor.It booted right up, as if nothing had happened. I tried rebooting and entering BIOS, to verify settings were still correct. At that point the screen froze, even though everything still appeared to be running. Subsequent boots resulted in no POST/Video/boot at all. Only PS/Fans came on.
I totally opened up the PC so I could closely inspect the Mobo/etc, as I suspected dirt/paper clip/etc. . It was then that I noticed the two electrolytic capacitors next to the two RAM slots [PC3200] had bulging tops and one had a leaky bottom. All other caps on the Mobo appear normal/good. I assume the capacitors are used for RAM refresh, as there is one by each slot [the reason the screen froze, it the RAM was not being refreshed, so all the video buffer has was its last input]. I will have to determine if capacitor replacement [personally or professionally done], is an option at all, somewhere down the line, but that is not germane to my question. I am inquiring if the processors are any good at all [the original and replacement]. Morever, if I install them into a good Mobo as a test will they do any damage to the mobo. I am building a new PC for myself with an Intel D915GEV mobo that uses a 775 processor.I have read a lot of documentation on the web about the 3.3V regulators in the processor/etc, but nothing definitive beyond that. If not, does anyone know another site to inquire at. [Not to **** smoke up your ***. but T/R forum IS the best !!]. I've looked at badcaps.com and capacitorlabs.com, but no luck. In any event, thank you all in advance for your time and consideration to this issue.


Sam [just another "OF"]

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Bad Capacitors

by TheChas In reply to LGPA 775 & Mobo Failure O ...

Most of the round electrolytic capacitors on a motherboard are for power supply regulation and controlling noise on the power supply lines.

2 things happen when a cap fails, the first is that the noise on the circuit increases. The second is that the cap can start to drain off power all by itself and effectively disable nearby hardware.

Failing caps on computer motherboards have been reported since around 2002. There have been several instances traced back to defective capacitors. However, the present working hypothesis is that the high frequencies on modern motherboards cause excessive heating in the capacitors and lead to self destruction of the capacitors.

As to changing capacitors on a motherboard, the question is how good are your electronic soldering skills and tools? If you have less than $200 (US) invested in your desoldering tools, I would not attempt removing the old capacitors.

Computer motherboards have 4 or more internal layers that connect to the top and bottom traces by delicate plated feed-throughs. It takes very little heat or force to fracture the feed-through and destroy the motherboard.

Even though I have performed a lot of electronics soldering professionally, when I have a motherboard with failed capacitors, I just replace and recycle. Basic motherboards are inexpensive enough to not make it worth the effort.

Chas

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