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Old 10-02-2019, 07:58 AM   #1
dicky96
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Default Asus P5S800-VM no POST

Hi guys, here is the latest motherboard I'm trying to fix just for the hell of it

ASUS P5S800-VM

It turns on/off with the ATX power switch, but it doesn't boot (POST 00 on my diagnostic card)

I tried another P4 CPU, no difference

I tried with or without DDR. No difference

I have Vcore 1.4V, Vram 2.6V, 3.3V to the BOIS, 5V, 12V etc. I'm using a known good PSU

I reflashed the BIOS - no difference

From looking around with my scope I think i have no system clock. I'm looking at the RTM363-655 which I am sure is the clock generator. The crystal doesn't seem to be oscillating (just some high frequency noise on one pin probably from the PSU). I have 3.3V supply to this chip. Nothing seems to be happening on the outputs.

I couldn't find the exact datasheet. I found this one https://datasheetspdf.com/pdf-file/7...K/RTM363-210/1 for the RTM363-210

Does anyone know if the -210 and -655 version of RTM63 have the same pin out & functions?

Are these clock generator ICs known to fail?

best regards
Richard
Attached Images
File Type: jpg IMG_20191002_134620.jpg (931.6 KB, 11 views)
File Type: jpg IMG_20191002_134626.jpg (1,020.9 KB, 8 views)

Last edited by dicky96; 10-02-2019 at 08:00 AM..
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Old 10-02-2019, 09:51 AM   #2
SMDFlea
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Default Re: Asus P5S800-VM no POST

Here`s some boardviews ,it might help with your repair.
Attached Files
File Type: zip P5S800-VM R1.01.zip (1.61 MB, 4 views)
File Type: zip P5S800-VM R1.03.zip (165.6 KB, 4 views)
File Type: zip P5S800-VM.zip (1.71 MB, 5 views)
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Old 10-02-2019, 10:45 AM   #3
dicky96
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Default Re: Asus P5S800-VM no POST

Thank you. That's much appreciated
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Old 10-03-2019, 04:32 AM   #4
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Default Re: Asus P5S800-VM no POST

Sorry to be a pain, I have openboardview but when I open one of those files i just see a large square with a few capacitors (or similar) on it. How do I get the boardview with all the components?


I had a look at the RTM363-210 datasheet again - link in post #1

Assuming that is basically the same as the RTM363-533 then i have #PD is high 3.3V so according to the datasheet the IC should be active.

#RESET is low but the datasheet says that is an open collector output

According to the datasheet Block Diagram 4, there should be control inputs for #PCI STOP and #CPU STOP but those don't appear to relate to any pins on the IC.

On the Xtal I have 1V on one pin and 1.5V on the other pin but it isn't oscillating.
Clock Outputs such as pin 21 and 22 are low. So it isn't working.

Should I now order an Xtal and RTM363-533, or is there some other possibilities I am missing here?

Also i notice there are some control registers and a serial interface to program the RTM363 output frequencies. But how does that happen unless there is a clock to drive the CPU in the first place, unless it is supposed to oscillate at some frequency like 100MHz by default at power on?

Last edited by dicky96; 10-03-2019 at 04:35 AM..
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Old 10-03-2019, 04:52 PM   #5
SMDFlea
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Default Re: Asus P5S800-VM no POST

BoardViewer will open .asc files .
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File Type: zip BoardViewer.zip (1.10 MB, 2 views)
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Old 10-04-2019, 03:58 AM   #6
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Default Re: Asus P5S800-VM no POST

OpenBoardView works fine with them too. You may need to flip the board pressing the space bar.
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