820-00164 SMC_RESET_L issue.

[JohnB8812]

Now my PPBUS is 16 volts and SMC reset L is 0 lmao. I can fix the 16 volts problem, but I have no idea on this SMC_RESET issue.

 

[JohnB8812]

Replaced all fets and ISL and still 16 volts lol I'm calling this a rabbit hole. I do wonder what your input is tho on what could be causing the RESET_L issue my guess is there is an internal short near the ISL causing the PPBUS voltage to go crazy and causing the SMC_RESET_L signal to get screwed up. That's my best guess.

 

[dukefawks]

Resistance to GND on SMC_RESET?

 

[JohnB8812]

Resistance to ground is high many kilohms to ground

 

[dukefawks]

ISL and FETs should always be replaced together. Bad ISL can pull down SMC_RESET as it is on that line.

 

[JohnB8812]

They were all replaced at the same time I had the SMC Reset Issue before PPBUS went high

 

[dukefawks]

Remove R7100 to isolate SMC_RESET from the ISL

 

[JohnB8812]

Without R7100, I still get 0 volts on SMC_RESET_L exact same resistance measurements. Would this not have to be internal to the board at this point? Especially since I’ve replace the SMC, U5110, ISL etc? JTAG was removed too so it’s not an issue

 

[dukefawks]

What is resistance to GND on SMC_RESET?

 

[JohnB8812]

Currently getting around 2Kohms

 

[JohnB8812]

If I inject voltage, my power supply doesn’t ramp up at all and nothing gets warm

 

[dukefawks]

2K is too low as there is only a 100K pull up. Only thing to do is to remove everything that is on the SMC_RESET line till the 2K goes away.

 

[JohnB8812]

Ok will try and see what happens

 

[JohnB8812]

I pulled everything and resistance is still 2.9 kohms ?

 

[dukefawks]

J6100 also? If so then it is indeed in the board and RIP.

 

[JohnB8812]

J6100 has been gone. This board came in pretty nasty so it doesn’t totally surprise me

 

[shanenin]

I know this is an old thread, but I am trying to make sense of it. is pin 8 input or output, created by the SMC or u5110? Based on the comment, connect pin 1 to 8 implies pin 8 is output on u5110, Is that correct? If that is the case, would the SMC be pulling it down to .89 volts?

 

[2informaticos]

Please open new thread...

 

[cryptopher]

Im starting to loose my head over this... Removed SMC and now I get 1.6v on SMC Reset again

 

[JohnB8812]

Open a new thread please