Have a Hac-20 board that was previously working and just popped one day. Sold it to a friend, they got a week of play time, went to bed and next day could not get it to boot again.
No obvious shorts, charging circuit is working, resistances seem to be right in the normal range, I am seeing a constant .07a draw on the board with just USB power plugged in. ENxx chip is also producing 3.3, audio chip has no obvious shorts and buzzes out to SCL test pad. I get the same current draw with the eMMC removed as well. I am also unable to get windows to even chime when I plug the board into the PC with eMMC removed. On my working HAC-20 board i get a .07 draw and then drops to 0. I checked all the first stage rails on 77620 and I get them all except for LD08
CPU Buck is producing all the rails I would expect, test pad directly under CPU is giving me 1.8v. Even though it tested fine and had no obvious damage, I removed and replaced the fuel gauge with no change. LCD connector did have a broken pin, it was removed with no change. USB port is pristine, no shorts, and diode readings are acceptable. The only thing that stands out to me is that missing 1.05v rail on 77620, but maybe even that is just a red herring? Judging from the behavior of my working board, it feels like 77620 is getting stuck on when it should be shutdown, but from what? Is there anything I can do to further diagnose what could be causing the issue, or am I at the “start replacing things one by 1 until it goes away” phase.
Unfortunately i do not have spare 776020A chips (just some H versions), and same goes for the CPU / GPU bucks used on this revision, would have to order those too (dont even have donors). So if there is anything I can do to help narrow things down that would awesome for my wallet (and sanity). I also don’t want to just randomly reflow chips without better knowledge, but if that’s a next step im more than capable.
Feels like this board is salvageable as it was completely functional before it left my hands. Personally i think their kid dropped it as I swore I noticed some shell damage that wasn’t there before, but thats just a guess.
Anything I can provide I will be happy to do so, thanks for the help!
Ordinarily you will measure USB current draw of approx 0.3 to 0.6A (on a 5V supply and the range is as a result of the monitor used) with or without the EMMC connected, and that’s with the battery hooked up (I’m pretty sure it’s the same without the battery too) anything else suggests a fault. - I don’t really use the Nintendo adapter to test USB current draw as my monitor doesn’t seem to like it so could be wrong but 0.07A on your working board seems low, are you sure you don’t mean 0.7A? (though I suppose this might be normal if battery is full)
Is this a Mariko rev?
What is the resistance to ground here? if it’s fine then is probably just not coming up as a result of some other issue halting boot (I’m guessing 1V3/1V35 is coming up in this case?)
This current measurement is with the battery disconnected (usb-c power only). With a battery connected i get a .48a draw as expected. The only reason I pointed this out was because with the working board, the same current drops to 0 as I guess the 77620 realizes there is no battery and just shuts everything down. With the broken board this .07a draw never drops down to 0 and shuts down.
I don’t think so? Its a HAC-CPU-20 board, running the 77620A and 77621 CPU/GPU bucks. I may be wrong here but i thought mariko updated to 77620H and 77812 CPU buck
If you referring to the TP / Passive attached to LD08:
~13k working board ~14k broken board. I do believe i have both voltage rails showing up around the 77620, if there is anywhere else I should expect to see these and should check I am all ears.
Pin was broken before i handed over the system, so no telling how long it was broken. As for the pin i do believe it is #24 when looking at the entrance. Maybe a picture will help, the broken pin is highlight in yellow.
I see, so yeah this is normal behaviour on a board with the braindead behaviour.
These board markings don’t really mean much and apply more to the board itself as opposed to what’s on it so I try to avoid using them. There are some common normalcies associated with this number but I wouldn’t steak my life on it.
But given the IC’s it seems like it’s a standard Erista board/SoC - the reason I asked is because you mentioned the CPU buck rail was coming up which your the third person to have mentioned this rail being present before high current charge being initiallised … I could have swore the (secondary) CPU doesn’t come up on Erista for a few seconds following prompt / hand in hand with high current charge (drop to zero then back up) This is something that I have to verify… for all I know the software has been updated which changes this behaviour since last I checked…If you have a known good Erista board it might be worth checking this yourself, just monitor the voltage at the inductor as your prompting and pay close eye to the USB current meter, if (secondary) CPU output rail is coming up on your working unit immediately following prompt then I’m remembering wrong or something has changed.(in which caser this is nothing to worry about)
Yeah that’s fine. I can’t say I’ve ever measured the voltage here on a braindead unit so I’m going to take a wild guess that this is the norm given that this (based on other recent posts) is the behaviour exhibited on Mariko rev boards.
And where does that pin go to using your known good with meter in continuity?
No worries but don’t know how much help I’ll be… these braindead states are the worst to troubleshoot… at least remotely.
I figured as much. One of the cases where you actually would prefer a dead short as it would probably be easier to track down.
Good to know, i had a feeling that was the case, but I always strive to provide as much detail as possible just in the off chance it is useful to those more knowledgeable than I.
I do, in fact the known working board I have been comparing to is the same revision and uses all the same IC’s. So I lucked out a bit in this sense. I will say that on the working board, when plugged in with USB power only, these voltages are not present (same with all the rails around 77620 on the working). I can plug in a battery on the working board, prompt boot, and record my results.
good point, I’ll take a quick glance at the board layers too and then buzz it out with my meter.
yeah, trolling through the numerous threads here and on GBA temp, it seems like a wild goose chase. At the least I am just trying to track my testing and results, as well as get pointers and other ideas from others with better knowledge. Hopefully through the process of elimination we can cut through as much noise as possible, if not oh well but at least i tried.
I did put both of the MAX chips on order anyways, never hurts to have spares in the end and if I do need one or the other at least it will be on the way.
that particular pin is tied directly to a capacitor on the backside of the board (would be NW of the 7720 if you had teh USB port facing south). Measured the cap and got a resistance to ground in the megaohms. Buzzer verified I traced the path correctly as I got a solid beep after soldering a lead onto the FPC pad and then probed the cap. I think perhaps next steps I’ll just do some basic readings on the surrounding pads and see if anything interesting pops up.
it is worth pointing out that said broken pin was actually located INSIDE the connector and was smashed up against the back of it. Like a true idiot, i forgot to test to see if said pin bridged anything internally before removing the connector. I got a little excited that I thought I figured it out and just forged ahead before testing.
Also had an idea. I just received an unpatched switch that unfortunately gives the dreaded failed to init eMMC message in hekate. I was thinking about popping the eMMC from my broken board into the unpatched switch, then booting said switch into hekate to verify the eMMC.
Hope here is that I could at least verify or rule out a bad eMMC from the process. I know the biggest danger here is burning fuses, but as the unpatched board can sideload anyhow (and is most likely now donor parts) I don’t see much risk.
Sure you can boot unpatched into Hekate then swap out the emmc and go into the emmc section to see if it read info or not.
FYI.label each one and Don’t mix them up before doing anything.
Yeah. This braindead state can be cause by any number of things which is why unfortunately there is no magic bullet. Hopefully we can start narrowing things down.
Where does that cap go? it would be unusual for a line to be traveling that far simply to terminate at a bypass cap which likely means it’s heading off somewhere else bit hard to tell where your at in that image but off the top of my head I think a few lines in that area relate to the 8316 IC maybe.
So, ive become better at using this tool to trace lines, but I am still no expert. From what I can tell, those caps do seem to be the end of the line? I tried my best to trace my work here in the image. It gets a little hazy in the third image since I guess some of that plane was eaten away, but isn’t just a ground plane anyhow? I did go down another few layers to check, that fat trace is just not connected to anything I can tell. Both caps in this area are tied directly to pins on the LCD connector, the one in question is actually tied to another pin on the frontside using a via, so we have a total of three pins connected to two separate caps on the otherside, but I am just not seeing where they connect to anything else.
Can thank my stream for that otherwise even that photo wouldn’t have been recorded lol. My main reason for streaming to YT is to have a nice record of my work that I can use to help troubleshoot if needed, anything else that may come of it is just a super bonus.
well, some hopeful news at least, I think i can rule the eMMC out. Popped it into an unpatched last night and hekate was able to at the very least read and show me the info on it. I didnt try to dump the partitions or anything, just verified i was not getting a “failed to init” message. I do have one of the logic analyzers that @sherrifbuck linked just the other day if that could be of use here.
Ground plane everywhere, is the pin in question connected to ground?
I’d verify all this yourself by putting your meter in continuity as this layer scans which while highly useful can be deceptive… you can strip back some multi core copper flex cable (more strands better) hook that up to your meter and probe to the other (or solder to the cap of interest) then with your meter in continuity use that multi core flex as a paintbrush to find where it’s connected (assuming it’s exposed on surface level)
Good stuff
You’d have to ask him about all that as I find it’s quicker to troubleshoot hardware wise, then ultimately narrow down from there as for me it’s quicker but you should give it a go
So the pin(s) in question are not directly linked to ground as i get no buzz from the pin to ground. The other side of the cap(s) these pins are connected is, however, connected to ground.
ill give this a go for sure, neat technique.
Yeah, ive been hesitant to use it as I have zero experience using this tool. Just wanted to point out it is something I do have available if it could prove useful. I do have plans on learning at least how to use it well enough to hopefully gain better insight, but as for now Ive put it aside to avoid muddying the waters.
I also did want to point i did watch a retrosix video on him diagnosing 1st stage boot issues (https://www.youtube.com/watch?v=LccZxG5cOTM) and he explicitly pointed out that missing rail i have on 77620 as not being a 100% positive indicator of anything being wrong. Went out to say on some boards it comes up, on some it doesn’t. I’ll definitely keep it in mind for later, but since I am seeing all my other first stage rails on this chip I do believe it is most likely not my issue.
Knowing that I do plan on focusing on the CPU buck next. Since I have confirmed my eMMC is at least readable in hekate, the eMMC should not be the issue. At the very least it is a place to start and focus energy on, i think in another week or so I will have replacements for it as well. Before I go reflowing or replacing anything though, it would be preferable to have some sort of sign indicating this is a next step rather than just crossing my fingers and praying. But hey, if thats what I have to do, its what I’ll do
bit hard to tell where your at in that image but off the top of my head I think a few lines in that area relate to the 8316 IC maybe.
