Charging but no boot - HOT 8316 IC

You don’t want to be checking values but rather checking continuity to/from destinations, diode mode is useless at the best of times but it’s particularly problematic in USB verification scenarios as you can get tricked. Resistance to ground is better but you can still caught out, so best to check continuity to/from actual destinations (and keep an eye on the resistance in ohms on your meter while doing so to ensure the continuous path is indeed actually low from one point to the next :slight_smile:

In regards to thermal cams, waste of money tbh outside of ovious failures. almost 50C would be quite easy to spot without a thermal cam, and i’d imagine it would show up with some basic rail checks in a few seconds, in your case possibly your SYS rail / Battery rail, in which case you’d check their resistance relative to ground, my guess is they are likely low, hence the heat (assuming this is indeed outside of normal operating temps / not charging the battery )

Sorry im learning. Sorry to op too. Didnt mean to be on his thread with my own issues but how can you tell if an ic is bad without no obvious shorts? I see a lot of people blindly replacing the m92 and p13usb. The only thing i see that make sense is getting the power draw at certain points.


Also i meant measurements from this break out board for i can compare to check the usb. Im definitely going to do more testing before doing anything

By measuring key rails / lines which have something in common with the IC in question, this could be voltage (to see if the rails being pulled down) or by (idealy) checking resistance to ground on said rail/s / lines. Dead shorts are not always the primary mode of failure, sometimes something could fail and drag a rail down to 120ohm (for example) in which case (where ordinarily it might measure 10k for example), provided you have a rough idea of what to expect or a known good donor to compare against (or check the forum) then you can identify the problem and resolve the issue.

In extremely limited cases and with very in depth knowledge of the target board, this can *sometimes be useful, but if your relying on others measurments and lack those things, then it’s pretty useless. Measurements your end up with will be marginally different to others (because of equipment difference etc), the measurments often and do show the same approx value for various fault conditions, likely the one you don’t know about and a whole heap of other issues. Best to avoid this approach for now as a beginner :slight_smile:

Yeah a lot of youtubers do this, infuriating isn’t it

you mean destinations? I can’t give you measurements for what I reccommended as it would just be me saying <1 ohm over and over :stuck_out_tongue_winking_eye:

For to/from destination continuity map, just have a search online, plenty of people have posted images, or if you have a known good donor, just buzz them out yourself in continuity for verification :+1:

Don’t apologise, we are all learning, and others might find this useful too :+1:

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Alright, I’ve got a breakout board delivering tomorrow and I’ll get that checked asap. As far as these key rails go, do you have a previous post or page that shows what to check and expect for the Lite? This one is quite the puzzle.


Got this online from a good switch for the breakout board also compared it to mines and everything looks fine. If you need it, not going be exact but should be in the range

Thanks you been a lot of help. I made a post if you have a chance can you please check it out whenever. Think i found something

Just join this forum. Trying to figure it out they wont let me include links

:+1: I’d also be taking a look at retracing your steps a little to just incase you got unlucky with the M92 IC, youd typically get an error code but sometimes you can get no boot also due to bad install / fake IC. If you have a donor with a known good IC, it might be worth borowing it’s IC to rule this out.

In regards to “primary rails” , this info I’ve posted in the switch category a fair bit so you should be able to find them and where theyre located (largely the same between revisions), most are around the main max PMIC, then 3V3PDR and SYS.

In you case though, given the symptoms your not only looking for deviations in regards to rails getting pulled low or short, but given the low current draw you might also be looking for open lines/ rails .

Pretty meaningless tbh as you can have normally open lines (as far as your meter is concerned in a given polarity) that are actually truly open as a rresult of a fault which you won’t detect and also vice versa. Then you can have parallel components on a given line and (as an example) one of the two could fail or the line to one could open, you’d still get a “good” reading on your meter but be blissfully unaware of the actual fault… in both cases, that’s before we even get into the resolution issues with diode mode.

As I said, it’s best to check continuity to actual destinations so you don’t get tripped up… You can continue doing it the simon says way and testing diode mode on things and instantly pulling out a thermal cam if you lke but just be aware you’ll be limiting yourself to the most basic of faults (and even then… ) and be classing 80% of all repairs as unfixable… bit like that scam artist youtuber with the funny accent Nor… ahem :stuck_out_tongue: You can only learn by doing which is why I’m trying to motivate you to figure this out :slight_smile:

Alright, I had some spare time today and did some resistance and diode measurements comparing against this youtube video (v=1fwaANg7464). I took a few screenshots of areas that had, what I felt were, notable differences and put the video’s measurement in green and mine in red.







I’m going to look for some rail measurement posts now and keep beeping away over here.

Lmao thats where i get some of this stuff. The funny accent youtubers. Your spot on man. They’re like im just going to change the m92 or ps13 cause of my experience without even doing any real testing. Im like huh

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Just so you know, watching that video had to be the most mind numbing and infurating thing I’ve watched :stuck_out_tongue: do yourself a fav and ignore it :slight_smile:

video title should be “Lets test things on every multimeter setting possible”, then let’s test every single testpad one at a time, at a time, on lines and “things” I very clearly don’t understand the purpose of :upside_down_face: christ, I’d be there all day just measuring a single board :wink:

Just stick to resistance and keep your black probe on ground. Once you find the locations on the forum just overlay them in an image and I’ll take a look

:rofl: oh my mind was definitely numbed alright

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Alright, my friend, I finally got the breakout board and took the readings in diode mode (red on ground, black on board test points). Compared to another “known good” post of these readings here in the forum it looks good to me, but I’d love a second opinion.

Ah, issues with trying to edit previous post. Sorry for the spam. Here’s what I was trying to add:

I still need to get those test readings around PMIC, 3V3PDR, and SYS. Hoping to get that today.

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Alright, I’m not 100% sure this is the area you’re talking about, especially because I didn’t see anything at 3V, but here’s what I read around the M92 and BQ chips. There was an audible electrical buzz while I was reading the capacitor with the arrow pointed to it. Not sure if that matters, just noted it.

If your not getting 3.3V following prompt to boot (either USB or power button) then suggest either USB/M92 or USB support circuitry issues or issues with the ENXX IC which generates 3V3PDR.

In regard to the USB, you wanna be checking continuity to actual destinations as I mentioned earlier on as opposed to diode mode, as outside of a quick and dirty rough check it doesn’t truly confirm any potential USB / open line situation.

Ah, that was helpful to point me to where to look for 3V. Here’s what I found at MAX77620H and ENXX:


All measurements are with USB and battery connected.

Sorry about that! I’ll look for a pinout/destination pic and re-test in continuity.

All continuity points are verified. USB port is good.

to relevant IC’s and not just back of th USB connector pins right?

So your getting 3V3 present at the EN IC (as you’d expect) but earlier you weren’t getting it at the M92 IC, it’s fairly important that you ensure you’ve definately prompted the console to boot if your going to be checking voltages like your doing :slight_smile: So I’d double check that

Yes, that’s correct. I followed a pinout photo that had each corresponding test point on the main board.

Where should I be seeing 3V at the M92? Where I got the 0V reading?

Is there an easy way to try to power on the board without plugging the side board in? I thought I saw somewhere there were some pads that could be jumped that would close the same as the power switch.