820-2850 no s3 rails

Chuck60

Member
At u7201
Ppbus_g3h=12.56v
Pp5v_s5 =5v
Pp3v3_s5 =3.3v

pp3v3s5_entrip1=800mv
Pp5vs3_entrip2=800mv
5vp3v3_reg_en=3.3v
Pp5vs3_vbst_r=5v
Pp5vs3_LL=0v

I’m seeing that both entrip signals are low so both s5 and s3 should be up. If I’m reading the schematic correctly. I have no short on s3 line. someone has already Been in this area and flux is all over it :/
 
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2informaticos

Administrator
Staff member
We take our time to write correctly here (even capital letters for signal names); why don't you do the same, as first interested?

Post some history fault, sometime helps.

Check R/C7224 and all resistors/traces from 5V_S3 area.
 

Chuck60

Member
Ok I will R/C7224 and all the traces.
History fault
MagSafe has dim green light.
PPBUS_G3H=12.56v
PP5V_S5 =5v
PP3V3_S3=3.3v
PP5_S3=0v
PP3v3_S3=0v
No fan spin. No shorts found on any of the above lines.
 

2informaticos

Administrator
Staff member
"PP3V3_S3=3.3v
------------
PP3v3_S3=0v"
Really?

Post again basic voltages for U7201, (when missing 5V_S3); pins 16, 13, 3, 8, 17, 6, 1.
 

Chuck60

Member
No I’m sorry 😐 PP3v3_S3=0v my mistake.
I will take the the pin voltages when I get home but I definitely don’t have PP3v3_S3
Thank you
 

Chuck60

Member
Oddly I was double checking the voltages and the first time PPBUS_G3H=12.56v A few minutes ago and now I double checked it and it goes to 11.59 and slowly drains.
 

Chuck60

Member
3V42_G3H=3.42v
PPBUS_G3H =11-7 but it doesn’t fluctuate it drains. I put probes on it. It goes to 11v then drians to 6-7v

PPDCIN_G3H= 16.71-16.30v fluctuating
 

2informaticos

Administrator
Staff member
Post basic voltages for ISL 6259, especially when PPBUS_G3H drains; pins 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.
 

Chuck60

Member
ISL6259

1=15.05v
2=16.17v
3=4v
9=0v
12=3.41v
13=3.41v
14=3.2v
15=0v
17=7.62v
19=5.05v
20=5.07v
27=7.74v

Q7085 CHGR_AGATE_DIV= 15v I believe the issue is with my voltage divider shouldn’t it be 6.5v
 
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2informaticos

Administrator
Staff member
There is no resistor divider, untill U7000 close it to ground.

Post R7080/81 and R7085/86 ohm values, measured onboard.
 

Chuck60

Member
I replaced u7000 and I have the same issue
But I noticed the PPDCIN_G3H= 16.71-16.04v fluctuating again I’m thinking there must be a loose connection or bad solder Joint somewhere there also flux around the mage safe and fuse.
 

2informaticos

Administrator
Staff member
Not relevant fluctuation.
Check solders and traces around U7000.

Remove F7040 and see if C7040 voltage is stable then.
Be sure C7025 is good; better to replace.
 
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