Gigabyte GA-H55M-S2 schematic

[nicolae788]

Hello,

I am looking for a schematic for the GA-H55M-S2/SK 1156 motherboard. Seems like a hard to find one.

The current condition of the board it's as follows:

- had a power MosFET blown , with no other major damages and replaced, checked for shorts in the VRM, everything looks ok.
- for safety reasons replaced also the ISL 63333 CRZ

The board exhibits a power on /Off loop without beeps or any image. The ON state takes about 2 seconds, then Off and then back On and does this forever.

I would like to inspect more closely the Super I/O Power On circuit and a schematic would help a lot. In the meantime i ordered an ITE 8720F super I/O because this was a model that i do not have at all in my inventory and i suspect it as being the culprit for all this, but...no hard facts here.

If someone has the schematic and can share it, this would be great.

Thank you very much for your kindness.

Alex.

[RJARRRPCGP]

Re: Gigabyte GA-H55M-S2 schematic

Someone reported this type of issue because of RAM, IIRC. Possibly not lined up in the slot correctly.

[nicolae788]

Re: Gigabyte GA-H55M-S2 schematic

Hi, thank you for the reply. I forgot to mention an important detail. This behavior it's present also without the following parts installed on the M/B :

- CPU, RAM, CPU +12V 4 pin connector,

It's like bare naked, the M/B . Normally under these circumstances it should fire up and maintain the cooler running, but the loop it's present. I have good +3V and + 5V stand by voltages. The +3V it's present at A14 on the PCI slot and the +5V it's present on the PWR-ON jumper for the front panel button.

With the 24 pin ATX connector and the 4pin +12V CPU connector, both connected to the M/B if i force the PSU ON by shorting the green wire with a ground the PSU keeps running, which means there is no short.

The same thing happens if i install the CPU and RAM...

Might be the SUPER I/O, but a schematic would help somewhat.


Thank you.

[seanc]

Re: Gigabyte GA-H55M-S2 schematic

We had about 15 of these boards do this.
Once sent back to Gigabyte and repaired, they would do it again and again. We have lots of unusable 1156 processors as the boards aren't available new and second hand is rare. The board failure has never fried our CPUs.
I doubt you'll ever fix it properly.

[nicolae788]

Re: Gigabyte GA-H55M-S2 schematic

Hi, thank you very much for your input. It surely doesn't sound very encouraging . However i will try to find out what the problem it's. It should be a bad component used in these series of motherboards and that's why i am searching for a schematic, to try to dig in as much as possible.

Have you observed any part that they might have changed when they were shipped back from Gigabyte?

[seanc]

Re: Gigabyte GA-H55M-S2 schematic

It only ever seemed to be the mosfets around the CPU that got replaced.
Most of the time we could see these had blown before sending them off.

If you replaced all of yours, you might have a working and reliable board. I always wondered if it was bad design or bad batch of defective mosfets.

[nicolae788]

Re: Gigabyte GA-H55M-S2 schematic

Hmmm , interesting... I actually found just one MosFET, not blown, visibly, but was shorted internally. I replaced just that one. Maybe there are others which have a hidden problem. I think it's time to desolder one by one all the MosFET's and check them for inconsistency.

However the need for a schematic remains open, so if anyone has that schematic and can share it i would be very grateful.

Thank you.

[hanybad]

Re: Gigabyte GA-H55M-S2 schematic

Hi All, nicolae788, Unfortunately I agree with seanc , I have a confirmed information regarding this MB model . It has an issue. You will suffer but you will scrap it in the end. Anyway, I will send its diagram to you next Sunday or Monday. Please just tell me which revision is this MB ?

Finally, sorry to ask, but since this is my 1st day here, I do not know how to attach the file or upload it here and I do not know also your mail. Help me to help you.

Hany

[hanybad]

Re: Gigabyte GA-H55M-S2 schematic

Hello All , here is the Diagram you ask.

[linhnguyenvn]

Re: Gigabyte GA-H55M-S2 schematic

Thank

[anhtu157]

Re: Gigabyte GA-H55M-S2 schematic

thank u!

[somebody777]

Re: Gigabyte GA-H55M-S2 schematic

Hello,

I am looking for a schematic for the GA-H55M-S2/SK 1156 motherboard. Seems like a hard to find one.

The current condition of the board it's as follows:

- had a power MosFET blown , with no other major damages and replaced, checked for shorts in the VRM, everything looks ok.
- for safety reasons replaced also the ISL 63333 CRZ

The board exhibits a power on /Off loop without beeps or any image. The ON state takes about 2 seconds, then Off and then back On and does this forever.

I would like to inspect more closely the Super I/O Power On circuit and a schematic would help a lot. In the meantime i ordered an ITE 8720F super I/O because this was a model that i do not have at all in my inventory and i suspect it as being the culprit for all this, but...no hard facts here.

If someone has the schematic and can share it, this would be great.

Thank you very much for your kindness.

Alex.

Probably CPU dead...

[samopjanb]

Re: Gigabyte GA-H55M-S2 schematic

thanks

[beal]

Re: Gigabyte GA-H55M-S2 schematic

thanks

[shaon_kof]

Re: Gigabyte GA-H55M-S2 schematic

Hello All , here is the Diagram you ask.

Thanks bro.

[ufuk4]

Re: Gigabyte GA-H55M-S2 schematic

Does anyone have any information about what the problem is? I have encountered the same thing after I replaced all 6 mosfets so it can't be the mosfets. After the repair it keeps power cycling on-off-on-off keeps on forever.

[victor_quiroga]

Re: Gigabyte GA-H55M-S2 schematic

Gracias

[ymz]

Re: Gigabyte GA-H55M-S2 schematic

thanks

[shaon_kof]

Re: Gigabyte GA-H55M-S2 schematic

Does anyone have any information about what the problem is? I have encountered the same thing after I replaced all 6 mosfets so it can't be the mosfets. After the repair it keeps power cycling on-off-on-off keeps on forever.

Try to measure the input voltage of Vcore(ISL63333CRZ) IC 1st. Does it getting the 12V+ and 5V VCC or not. Also the RAM voltage which is 1.5V. Then let me know.

[marcelo eduardo]

Re: Gigabyte GA-H55M-S2 schematic

Hello All , here is the Diagram you ask.

Thank @hanybad