A1398 820-3071-A with no image

[2informaticos]

That's good.
Be sure R8930/60 and C8930/65 are good.
Change U8900, if you have good one available.
Apply power and see what happens.

 

[hgoncalves]

Still the same (0.280A of consume in PS)

PPBUS_G3H = 1.6V

R8930/60 and C8930/65 are good.

U8900:
16 = 0.29V
17 = 1,54V
25= 0.29V

 

[2informaticos]

"PPBUS_G3H = 1.6V"
Post again diode mode.
If low again, then change U8900 and the 3 MOSFETs from GPU power supply.

BTW, you can consider to disable GPU by hardware mod.

 

[hgoncalves]

After powering it up, PPBUS_G3H has shorted again (29 ohm and 0.0530 mV on diode mode).

I don't mhave other U8900 (but this is the second one). Can i measure it some how, to see if it is good?

Can you, please, specify witch are the 3 GPU MOSFETs (are they Q8930/31 and 61)?

 

[2informaticos]

Yes, these are.
For some reason, Q8930 got burnt again.

"BTW, you can consider to disable GPU by hardware mod."
You should consider this the best option now...

 

[hgoncalves]

I've seen some pictures of disable GPU by hardware mod, and it seams a prety meess thing to do, and i cant find some good procedures on the net. Do you have any procedure to do it, that i can follow?

 

[2informaticos]

The hardware mod is already posted on the forum...

GPU Bypass for 820-3332?

I've heard of a possible bypass for the GPU on this model, something like the 820-2915 bypass? Does anyone know if this is possible? I've seen mention of a Facebook page but I can't access it and have tried with no luck to join the group.

boards.rossmanngroup.com

 

[hgoncalves]

Hi,
I've made the hardware mod, but now, the fans are always at full rmp.
What shal i do?

 

[2informaticos]

Do you get internal image now?

 

[hgoncalves]

Hi, Yes i do.
I've just made the step 2. It's needed to do all 3 steps?

 

[2informaticos]

You should disable GPU power supply anyway.

Fans run fast from the first moment, or ramp up after 20-30s?
Check the temps with HWMonitor.

 

[hgoncalves]

The fan started to full speed after a few seconds. It was a bad trackpad cable.
after replacement all went ok.
TKS!