Ms7817 (msi h81m-e34)

[bootlegger17]

Hi,

I have a troublesome motherboard. It will not start. PSU I believe is OK, and have swapped for like PSU and system still fails to power up, leading me to believe its a motherboard fault.

No activity from power switch invokes the PSOK/PON line on the ATX.
If I short the ATX green line to GND (for PON), the CPU and PSU fan spin briefly, then stop. There is a constand 5VSB line from the PSU into mboard.

It is very difficult to trace anything on the mboard, but I have found what I think are two suspicious things;

1) the 3.3v lines on the ATX connecter on the mboard all seem to be grounded - the 5V and 12V lines are not - I assume this is incorrect.

2) I have found a SOP-8 chip that seems to have two grounds, one on pin 5 which is correct, and also on pin 7, which is supposed to be the VOut - I assume this is incorrect? This is close to the USB pin outs section.

I dont think the two can be tied together - a vout and 3.3 line in would compete, so is there something common that could link the two which could be grounding them?

Regards
Jason

[bootlegger17]

Re: Ms7817 (msi h81m-e34)

Having read a post of similair nature on about another board on this forum, i have removed the realtek network controller, but the same fault still exists.

[bootlegger17]

Re: Ms7817 (msi h81m-e34)

anybody know where i can maybe get hold of a schematic for this mboard.
I have searched google and found about three references so far, but all go off to foreign (vietnam/thailand/phillipennes) based websites which I can not understand, and I think they are subscription sites that you need to pay for releasing the files.

[piernov]

Re: Ms7817 (msi h81m-e34)

Schematics attached (hope it's the right one).
Can you take a picture of the SOP-8 chip and its surroundings? What is its part number?
What is the actual resistance you measure between this Vout and ground, and between the 3.3V line and ground?

[bootlegger17]

Re: Ms7817 (msi h81m-e34)

thanks for the schematics.
However seeing on the last page the PCB1, that is not my PCB
FYI its this one;https://www.bhphotovideo.com/c/produ...therboard.html

As for the SOP, its by the realtek, and I have removed it, and tested pins and the two are not grounded to each other when off the mboard so I dont believe the realtek or this sop8 were at fault. I cant recall the sop8 ID so would need to have a look at it again, but this doesnt seem important now

[bootlegger17]

Re: Ms7817 (msi h81m-e34)

The sop8 was a uP0104S pgp51w. It was pins 8 and 6 grounded not 7 and 5 as previously mentioned

[brutech]

Re: Ms7817 (msi h81m-e34)

I have a H81M-E33 which is a MS-7871 ver 1.2 which won't start.

Installing a PCI-E post card, no 3.3vsb was present.

The sop8 was a uP0104S pgp51w. It was pins 8 and 6 grounded not 7 and 5 as previously mentioned

If you look at p24 of the schematic you'll see pin 6 and 8 are grounded. You'll also note that it shows that U16 has 9 pins not 8 - pin 6 is listed twice.

On my board, tracing from the 10K resistor then pin 6 should be Vout.

My board is also missing EC22 (see attachment0 and the pads for this are shorted too.

Can't find a datasheet for up0104s.

[brutech]

Re: Ms7817 (msi h81m-e34)

tested pins and the two are not grounded to each other when off the mboard so I dont believe the realtek or this sop8 were at fault.

Missed that first time round.

[brutech]

Re: Ms7817 (msi h81m-e34)

U16 has 9 pins not 8 - pin 6 is listed twice..

Or 9 is the pad on the back

[piernov]

Re: Ms7817 (msi h81m-e34)

If +3VSB is shorted it's usually the Ethernet controller.
Check if it's heating up.
Otherwise, inject voltage, and search for the component that's heating up.

[Jamescl]

Re: Ms7817 (msi h81m-e34)

Thanks

[miloud]

Re: Ms7817 (msi h81m-e34)

Thanks