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820-01814 No PP1V8_SLPS2R

prodigy83

prodigy83

Member
My refernce only: TT9752

I get no PP1V8_SLPS2R, so cannot do DFU.
I have replaced U7000, still same results, 5V on the meter.
PBUS line coming from U7000 is 1v.
5v is present on R7020 pin 1.
PPVBAT_G3H_CHGR_REG also has only 1v.
What am I missing here? No liquid damage at all. The board is very clean.
 
2informaticos

2informaticos

Administrator
Staff member
Remove F7000/1 and check C7050 voltage.
If still low, post U7000 basic voltages; P_IN, AUX_DET, SMC_RST_IN, VDDA/P, EN_MVR, CBC_ON, A/BMON.
 
prodigy83

prodigy83

Member
2informaticos said:
C7050 voltage
Click to expand...
C7050 fluctuates from 1.5v to .900.
P_IN 5.12
AUX_DET 0
SMC_RST_IN also appears to be CHGR_RST_IN? I get 0v. TP_CHGR_SMC_RST_L I also get 0v but the board is not hooked up to a trackpad.
VDDA 5.06
VDDP 5.06
EN_MVR 0
CBC_ON Don't know how I am going to test this one without removing U7000 or U7800.
AMON .037
BMON 0
 
2informaticos

2informaticos

Administrator
Staff member
"AUX_DET 0"
Fix it!

Check first diode mode to ground there.
If good, then check R7015.
If short, or low value, then should have bad U7000.
 
prodigy83

prodigy83

Member
I have replaced U7000 3 times total now with a brand new one but I keep getting the same result.
r7015 pin 1 has 5.1v, pin 2 has 1.266v. I get no shorts anywhere (actually just found one). Diode mode on both pins is OL.
PPVBAT_G3H_CHGR_REG Now seems to have a short. Thermal cam shows U3900 getting hot. I was getting a short here before too, but it went away. My ground cable broke off from the board pretty easily, so I may have had a bad connection when testing. Any hope from this point?
 
2informaticos

2informaticos

Administrator
Staff member
"pin 2 has 1.266v"
The reason of checking that was
"AUX_DET 0"
You can save time posting accurate information.

PPVBAT_G3H_CHGR_REG is same as PPBUS_G3H; it is not battery power rail.
Allow 10-15s before checking diode mode, or ohm scale, on any power rail.

"C7050 fluctuates from 1.5v to .900"
Did you've checked that with both F7000/1 removed?
 
prodigy83

prodigy83

Member
2informaticos said:
"pin 2 has 1.266v"
The reason of checking that was
"AUX_DET 0"
You can save time posting accurate information.
Click to expand...
Sorry about that. I forgot to mention I replaced R7015, and R7021, they looked like they had eyes in the center.
I also replaced C7023, C7080.
When testing everything again I stuck back on the 2 fuses F7000/1.
I did also remove R7060 at one point to further verify things. I did stick it back on but below I will list what it is when off.
Just removed F7000/1. PPVBAT_G3H_CHGR_REG still fluctuates. With these 2 fuses still removed, and now R7060 removed, pin 2 where R7060 was at, starts out at 1.3v but voltage drops slowly after watching it for about 30 seconds.
R7063 has 0v.
C7064 both sides have 0v.
C7020 both sides have 0v.
 
2informaticos

2informaticos

Administrator
Staff member
Put back R7060; you can't work there without it.

Post exact ohm resistance over C7020/23.
Keep F7000/1 removed, until get correct C7050 voltage.
 
prodigy83

prodigy83

Member
My mistake, I have never had to do that before, I am ignorant on this way of measuring. Which pin would I place these on, or does that matter? As I look closely, it appears there may be a broken trace going from pin 2 of C7020 to the U7000 chip. Going to lift U7000 and check it out.
 
prodigy83

prodigy83

Member
Trace appears fine, my tweezers I think may have pulled up a small area of the board but continuity is all there, and everything seems level. I stuck another new U7000 chip down. Placed the 2 fuses back in place, but still no more than 5.14v from the meter. What next?
 
2informaticos

2informaticos

Administrator
Staff member
So, what's the exact ohm resistance measured between C7020 pins?
As per schematic, you should get 2 ohm.
Test the same for C7023.

Keep F7000/1 removed; until get correct C7050 voltage.
 
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