820-3437-B No charge light PP3V42 present

2informaticos

Administrator
Staff member
First, to clarify your confusion.
Amazing to heard you checking between ISL6259 pins out of board!!!
I just hope you will do that ONBOARD next time.
We needed to know the resistance of R7120+21+22 and R7150+51+52 respectively; not internal chip resistance.

Do you get 3V3_S5/SUS voltages now?
The board has any reaction when pulsing power button?
 

posarah

Member
Yes 3V3_S5 and PP3V3_SUS are present. Yes shorting the power debug switch pulls the reset line low and is resetting the SMC.
.
 

2informaticos

Administrator
Staff member
"and is resetting the SMC"
What this means?
You've checked some signal, Isuppose.
Can we know which is???

SMC_ONOFF_L should NOT reset SMC.
You make some confusion there!
 

posarah

Member
I checked both SMC_ONOFF_L and SMC_S5_PWRGD_VIN and both were dropping to 0 when shorting R5115. Is there a particular line I should check? I wanted to check a few other SMC outputs but they were missing, ie 0V. WIFI enable on SMC pin 63 for example.
 

2informaticos

Administrator
Staff member
If charger is connected, S5 voltage MUST be steady.
Did you test the board alone on the desk?

When trigger SMC_ONOFF_L, you should note a drop pulse at PM_PWRBTN_L (at same time).
Be sure SMC_RESET_L is stable (all the time); no reaction at SMC_ONOFF_L allowed.
 

posarah

Member
Yes PP3V3_S5 Is steady 3.33V. Yes board has only been tested on the desk nothing plugged into the board, besides the DC in board obviously. Everything else is either removed from the board, or did not come with the board as this is a ebay "untested" job. PM_PWRBTN_L is 3.41V steady. 0.357V When I short SMC_ONOFF_L. SMC_RESET_L is 3.38V and shorting SMC_ONOFF_L does not change it.
 

posarah

Member
Something on the ISL line most be shorted as the ISL is now getting really hot when it was not earlier. That explains why the original failed, but none of the immediate surrounding components are reading short nor getting hot only the ISL itself.
 

posarah

Member
Looks like I've got another dead ISL. Checked all the components around it and they all seem fine. Checked which pins do not go to components in the area and checked them and there also fine. The only one which is short is ISL pin 24 CHGR_UGATE pin 1 of Q7130. Confirmed on two donor boards that's not suppose to be short. Removed it but the lines still short and there are no other components on that line.
 

posarah

Member
Ok U7100, C7125 and Q7130 have been replaced. Pin 1 on U7100 is now reading 330K ohm. Resistance between pin 17/18 is 3 ohms and resistance between 27/28 is 19.8ohm.
 

posarah

Member
ISL is still getting really hot, and looks like R7105 is blown again. Not as much as before though, now it's only gone up to 70 ohm.Pin 1 on R7105 is reading OL. Replaced D7105 now pin 1 on R7105 was reading but I didn't note it down and now when I go to measure it jumps between .367M and OL. Diode mode just reads OL. Is there any other components on the 3437 or 165 that we can use as a temporary replacement for R7105? I've already stolen that exact resistor off both my 3437 and 165 donors and searching for a 20 ohm 603 resistor for both schematics came up with nothing.
 

2informaticos

Administrator
Staff member
R7105 can only get burnt because of U7100, or C7105; did you change that cap?
You can use 4.7-27 ohm for R7105, without problems.
 

posarah

Member
Thanks I do have some 4.7 ohm so I'll use that for now. Yes C7105 was changed, though it was from a donor board so it may of been damaged though it did not read short nor does it now. Is it worth changing the mosfet Q7155? I was always taught when changing fets you should always change the pair and their controller. Also for Q3005 is it normal for it to have a slight brass colour to it? It's measuring fine but it does have that "i've been extremely hot in the past" look to it. Though both my donor boards have the same tinge to them so it's hard to tell if that's just normal or not.
 

posarah

Member
Ok I reflowed the whole ISL area & I replaced C7105 again. I used r7700 on my 3437 donor as a replacement for R7105. pin 1 R7105 is now reading 60K ohm .445 diode mode. Same on pin 2 of R7105. Removed F7140 C7140 voltage is 0V. The battery is not plugged in though, that should only have voltage if the battery is connected should'nt it? PPDCIN @ C7130 is 16V but at F7140 we have nothing on both sides.
 

2informaticos

Administrator
Staff member
If no voltage at C7140, removing F7140, then the problejm is on U7100 area for sure.
Keep the fuse out and post basic voltages for U7100; pins 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.
Use surrounding components as test points!
 

posarah

Member
I'm awaiting more ISLs, I think the ones I got are dodgy and R7105 has blown again twice with these "new" ISLs. I used a 10 ohm is the power rating important? I used a 1/16 10 ohm as it was the closest I had to the 1/10W 20 ohm. I've buldozed the whole ISL section and replaced everything and now am waiting for new ISLs to arrive. Something keeps blowing R7105, and I'm suspecting it's because the line off pin 1 is reading OL

What should diode mode read on C7116? On one donor and this board I have OL on the test pad, OL on pin 1 and 0.122 on pin 2. On another donor I have the same bar pin 2 which is 0.46. Seems a bit low 0.122.

I blew away C7116 can C3294 be used as a replacement? I don't have anymore 470PF 16V closest I have is 330 like C3294.
 

2informaticos

Administrator
Staff member
1/16W is less power than 1/10W; so 1/10W should be better even to use.

Did you check diode mode on pin 2 of U7100, w/ and w/o C7105?

You can try 330pF instead of 470pF for C7116.
 
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