820-01598

Mac Tech

Member
Hi everyone.

I have this plaque, liquid drop. Coffee.

The machine has 20V and consumption of 500ma.

I have ALL_SYS_PWRGD
I have CPU voltages

I am missing PPVCCEDRAM_S0_CPU.

This voltage comes out of U7710, the activation PVCCEDRAMS0_EN_FILT_BUF
I'm missing, it comes from U7712.

U7712 would like to know how this circuit works?

I understand through the PDF that it is activated by PVCCEDRAMS0_EN_R, it comes from R7758 and it comes out of U7711.

U7711 has PP3v3_S5, has ALL_SYS_PWRGD_R, but does not have PM_OPC_ZVM_L.

How should I interpret this problem?

I already restored the system, it gave me error 9.

Error 9, disconnect coils from the CPU and restore without problem. I understand that I have the problem in DDR or CPU.
 

2informaticos

Administrator
Staff member
Not sure when this voltage should appear.
Check it on good working board.

It doesn't even appear on power on sequence.
Probably comes on later, depending of the CPU requirments.

What is the CPU core voltage (L7210) after 10-15s?
 

Mac Tech

Member
when removing U7711 the DDR voltage appears 1V.

Check another board 820-01987-a and that voltage "signal" CPU_ZVM_L does not appear at any time.

Change U7711 without positive results.

I have a 820-00850 with the same problem.
 

2informaticos

Administrator
Staff member
"that voltage "signal" CPU_ZVM_L does not appear at any time"
Not really true!
The voltage doesn't appear, but the signal yes.
Keep in mind, the ending "_L" means signal active low; CPU_ZVM_L is active with 0V.
If working board gives same level, then your problem is not there.

"What is the CPU core voltage (L7210) after 10-15s?"
???
 

2informaticos

Administrator
Staff member
Heating up is not sign of boot.
CPU doesn't run in fact.
When CPU starts to work, you should note dynamic changes on its core voltage, according with its activity.
 

Mac Tech

Member
machine 820-00850 that had almost the same problem, I solved it with apple configuration 2. Restore.
 

Mac Tech

Member
yes of course, I restored but I had to disconnect the power of the cpu.

Because connected it gave me error 9
 
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