P4C800 deluxe memory problem

[jlavi]

I've over 4 years old P4c800 deluxe motherboard which has been
running 24x7 last 4 years. It has 8 OST RLXes as VRM output filter
and about 20 OST RLS here and there.

The machine booted itself and failed POST by saying "bad bios
checksum". I have 4 pieces of Kigston 1GB 400MHZ ECC DDR dimms
and one of them seems to have failed. Normally I would just order
a new DIMM and continue using the board without giving a second
thought.

However, now having reads warnings about OST caps, I consider
recapping the board or having it recapped, even if it seems to
work -- except that one memory DIMMS has now broken. I've had
reasonably well ventilated Antec case and CPU temp has usually
been 30 degress Celsius or slightly abobe and the same for hard
drives. Still, the airflow aroud memory banks may not have been
that good because of the cables and case structure blockking
flow.

Here a some pics of the caps. I don't see real bulding, but many caps
have 4 hang-gliders like vents, which was discussed in
the thread Asus TUSL2-C Ost recapping.

OST RLXes VRM output

Memory bank

Another memory bank cap

Another memory bank cap

One more close to the memory bank

Clock generator

Caps near AGP slot

[bgavin]

Re: P4C800 deluxe memory problem

Recap everything from 470uF and up. Use premium caps. Buy them here from the board owner (Topcat). He has everything you need to do a first-class job.

If you have not recapped before, read the Stickies on soldering tips. Read and Understand. There is a wealth of knowledge here. If you are a product of Sacramento Public Schools, have somebody read to you. There are no Books on Tape for the stickies...

[jlavi]

Re: P4C800 deluxe memory problem

Thanks for the reply. I have previous soldering experience but to
save time I asked a quote from local service, but they did not
bother to aswer. I am located in Finland, so Topcat's service is
not available.

I've tried cleaning holes with needle on a junk board with
employers JBC pro soldering station. This works, but cleaning tin
from the other size needs extra work.

I then bought Weller desoldering iron with my employers expense.
Already with a little testing I can say the device is
fantastic. Removing cap lead and cleaning the hole in a single
heating in 5 seconds, no tin residues and minimal stress on PCB.

I am going to replace 1500 uF 6.4V OST RLXes with the same value
Panasonic FMs and 1000 uF 6.3V OST RLSes with Panasonic FKs or
FMs. I am still waiting for some Panasonic FMs to arrive.

Before removing the caps I am testing with Memtest86 if it was
just one bad memory DIMM. With broken dimm replaced and 4 dimms
inserted the slot 0 (closest to CPU and NB) gives large number of
recoverable ECC errors, about 3000 erros per hour and about 5-10
non recoverable errors per hour. Switching dimms between bank 0
and another bank made no effect, and errors repeated on slot 0,
so sounds like a power problem in slot 0.