Switch Screen Artifact and then black screen

I have a damaged switch with an initial charging issue. I have replaced the m92/bq/p13 and fuel gauge. Now it is charging 15V 0.4A ish. I could boot up in hekate and I tried to charge the switch (within hekate). After charging for 5 min or so. I noticed the hekate screen is glitching/ artifacting then the switch would only boot up in black screen (backlight lit). LCD IC is outputting 5V i believe instead of 15V for regular display. I am unsure if I should replace LCD IC or reball CPU or MAX PMIC or reball ram?

Please advice. Than ks

Hey man,

Try loading the Biskeydump payload, if you get a display here and if it has artifacting, then it’s likely a ram/SoC issue or a joint issue between them and the board.

You can then try putting downward pressure on the Ram ICs and see if that resolves the artifacts for confirmation, though sometimes this doesn’t work.

Failing that, I’d check your 8316 IC for you positive and negative 5V rails

Hey Severence,

I have tried biskeydump, and not getting any display this time. I have reballed the SOC and replaced a donor 8316 IC. Is there any method to test RAM IC ?

I have tried to use a thermal camera and found heat spot on the 8316 IC. Is that normal? Would you be able to pinpoint where the positive and negative 5V rail ? I have downloaded the 8316 datasheet but dont know how to read it properly sadly.

I see, the backlight driver will not boost the output voltage until the LCD connected, I presume your stilll getting backlight when connected?

In future, I’d start with reflowing/reballing ram first, given how sensitive the Switch SoC is to heat.

Yeah no worrries. Here’s my diagram detailing the pinout

Check your getting your +/- 5V outputs at the points detailed. Also check that your getting your enables which is a 1.8V high at the two highlighted spots.

Also might be worth measuring your primary rails resistance relative to ground on the surrounding main PMIC output inductors juss to ensure everything checks out here, might be one is short, which I would have advised checking with the So out of circuit if thats the case.

The LCD is connected while testing biskeydump and I am getting the backlight. ( I could dump it with biskeydump within tegrarcmgui tool (2nd page)). Another interesting note is that when I try to mount Memloader of Emmc rawnand, Tegrarcmgui just freezes.

I was a bit too excited with the stencil, preheated and toke out the SOC :sweat:

I am getting +/-5V on the Vout-1 and Vout-2 as well as the 1.8V for enabling ( when injected hekate/ no image / only backlight)

I believe my 1V35 (Blue) is a bit on the low side. Is this the rail connecting all the components? I have recently got a thermal camera for imaging and found that the 1836 IC and main PMIC heat up while hekate is injected. I thought the 1836 IC does not generate any heat.

Haha, completely understand :smiley:

Think we can rule this out then. I guess the LCD connector is all good and there’s no bent pins etc?

What’s the resistance?

This is just a misc SoC rail

I couldn’t say, sorry, I don’t use thermal cams as they just send you down a rabbit hole more often than not, afaict if your getting your enables and the outputs are being generated the IC is most likely fine.

I recently replaced the LCD connector. and when i tested it yesterday, one of the pins shot out from the back of the FPC connector. I will have to order some more to check. Aliexpress has some used LCD Fpc connector label as new. I think I had use a refurbished connector.

I have checked it again, I am getting 1 M Ohm on a fluke 17B+. I have compared with other ones it seem okay now.

I am scared that reball skill is still lacking, might have to do it again.

I see I see. I am not sure where to go from here since most of the PMIC rail looks ok. I will try to check for shorts everywhere. My suspect are Emmc/Ram/SoC/PMIC

This typically happens when the solder joint was bad, and the ribbon snags on it on entry, if the pin is still present you can push it back in and resolder it.

I would reflow Ram just to rule that out, I’m just guessing but I think that was your original probem.

You can rule out the EMMC as Hekate will boot and dispay with or without it.

The PMIC I would be surprised. and that leaves Ram and SoC but I would wait til you’ve resolved your LCD connector issue first before doing anything else :slight_smile:

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Hi guys, I got a docking shows perfect but not dislay on LCD(backlight on) Switch today.
Vout-1 and Vout-2 have -5.4v present. no damage on LCD connector, ruled out lcd as well.
Any idea, or what’s next I should check?

Never mind, I figured it was one of the LCD connector pin got loose solder joint.
Here is my diode measure of lcd cnnt. For anyone in the furture to cross reference

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