Thanks for sharing this diode mode values! Did you made them your self or is there an place for all the files? Is there an way to support and help with this?
Just some news from my side, I ordered some chips and an emmc to go further in the repair (if I can).
I finally received my chips and a new nand module.
I’m now facing the following issue:
- without any Nand connected, I can boot in RCM mode (TegraRCM recognized the device).
- with a Nand (the faulty one or the new one) connected, I cannot boot in RCM mode.
Any clue ?
EMMC is on the 3V3 rail and 1v8 rail, the issues your describing indicate a short on the emmc itself on one or both these rails, when connected to the mainboard it is preventing it from clearing a boot step.(because of the short)
Measure resistance to ground on the disconnected EMMC on these corresponding rails using the connector pinout above (checking opossing side on EMMC module) and comparing to a known good.
You might find the EMMC might require reballing or failing that dumping on PC with EMMC > low voltage adapter (SD/MMC) and the data transferred onto a good EMMC module
Hi, thanks for your help.
I do not see any pinout on your message, are you referring to an existing one ?
Also, I have 2 different emmc. One from origin, another bought to try to fix the issue. Could the rail voltage issue could be linked to something on the main board itself ?
Yeah, the one posted earlier by Calvin, mirror it to the opposing EMMC module connector and check the corresponding pins.
If the other is a known good then yeah it’s possible the issue is on the mainboard itself, after verifying resistance readings on the EMMC module and comparing to a known good I’d then set about verifying resistance readings on the relevant rails on the mainboard also.
Happy new year to everyone around 
I finally took the time to measure voltage and the stuff in diode mode.
I do have the good voltage values at indicated pin.
Regarding value in diode mode, at about 10% I mostly have the same reading.
Anything else I good check on the mainboard and the two emmc I have?
Happy new year!
Instead of diode mode check resistance instead… diode mode can be misleading
sorry, I mislead your resistance measurement request : I was measuring in diode mode on the mainboard connector itself.
do you mean I should work on the unplugged emmc, flip it and measure resistance between each pin of the connector and what (the big pad covered by glue, after some glue removal) ?
just a quick addition:
when the emmc is plugged and the battery is connected to the mainboard, I can see the 1.8V on the rails of the emmc (middle probe points), but no 3.3V where I should.
Hi,
When i say measure resistance, i mean on the EMMC module disconnected on the relevant rails, which in this case is 3V3 and 1v8 relative to ground. Don’t worry about the other pins for now.
The same on the mainboard, battery disconnected, and resistance on the 3V3 rail and 1V8 Rail (pins).
If 3v3 (voltage) isn’t present then that spells problems, if it’s not present when EMMC is connected then we need to determine if it’s the EMMC putting a fault on the board or if it’s an existing problem on the board itself and when the EMMC module is connected it loads it down to much triggering the fault etc.
If you can take the resistance readings on both the board and EMMC module while disconnected then we can find the cause
Thanks for the explanations.
I have between 0.06 and 0.07 ohm on all 3.3V and 1.8V pins, on both the mainboard connector and the emmc. Does it seems correct ?
Sorry I’m a bit confused, just to confirm.
Your getting those readings measuring on the disconnected EMMC module itself?
And your getting those readings measuring on the mainboard itself while the EMMC is disconnected?
Can you also confirm if your using a manual ranging or auto ranging meter?
Hi, yes.
I’m using the multimeter (brymen 867) in ohmmeter mode, using auto ranging or manual range.
Both for the mainboard and for the emmc measured while battery, power and emmc are disconnected.
What kind of values should I be reading ? I’m assuming I’m just getting nonsense.
Thanks,
Yeah the readings aren’t making sense to me.
A reading of 0.07 ohm on the 1V8 Rail indicates a dead short but not only that, it tells me it would be drawing >25A current 
If this was actually the resistance, I can’t imagine it maintaning it’s voltage of 1.8V at those levels, and instead I’d guess it’d possibly trigger short circuit protection and you’d actually measure 0V with battery/power connected.
Can you confirm the voltage reading on the 1V8 Rail on the mainboard with the EMMC disconnected?
And do you have a spare meter you can verify with? though I’d be suprised, I hear Brymen meters are excellent in terms of there reliability and protection etc
Seems I was stupid enough to measure incorrect pads (the 4 to-ground-soldering-part of the connector)…
Here are the readings made on the mainboard taken out from the chassis:
3.3V rails : unable to read whatsoever, the measurement keep fluctuacting (goiing from Mohm and decreasing continuously) : origin of the emmc issue ?
1.8V rails : 21.2 Kohm
On the EMMC itself:
3.3V rails : 15 Mohm
1.8V rails : 445 Kohm
From memory charging megs on 3V3 is normal depending on probe polarity.
Unfortunately, i don’t have a good feeling about your 1V8 rail…I’ve seen this before.
Check this out if you want a good/bad read 
> tronicsfixforum (dot) com/t/fix-the-lifted-off-solder-pad/4031/65
If you reverse your probes (change polarity, red on ground black on 1V8) on the 1V8 Rail and post your resistance readings.
Unfortunately it would seem something has happened since the beginning of this thread, originally you were able to boot hekate with the EMMC installed and now you can’t, coupled with the readings on 1V8 i have a bad feeling damage may have been inflicted on the SOC by probe slip/bridge
You might be right indeed.
The fuse (down the USB port) had blown and was replaced since the origin of the thread.
I have 4,87 Kohm when reversing polarity during measurement on the 1.8V rail.
Reading on the side A (as suggested) are fluctuating for component 5 and 6.
Could a blown MT92 cause this behavior ?
That’s interesting, do you have any idea what caused it to blow? Any signs of rework on the USB (melted/charred plastic, solder etc)
Visual inspection of the USB internal contacts and external pins all look good?
possibly, it’s directly connected to the 1V8 rail (as are a lot of other IC’s) a fault condition here or a bridge on that specific pad could in theory trugger the fault.
Did you replace the M92 IC or reflow it at any stage?
Yeah I’m getting Déjà vu here, it’s not looking good.
The 3V3 rail (or pin/pad 6 on M92) measure as follows on my board/s
My pin 6 black on ground 16.6k and reversed is approx 150k
So it would appear If your getting fluctuating/charging resistance readings here (both polarities) it might also indicate a problem on your 3V3 rails - if it’s high megs both ways then something has likely gone open circuit on this rail
I haven’t change the MT92 yet as the console was originally booting in hetake without issue.
Originally, the issue with the console was that it would never boot (from one day to the next).
I could perform basic checks with the help of Calvin and soon was able to boot using hetake.
But I could never boot on the stock rom (the nand) or the emuEMMC created (it reboots).
I assumed the issue was linked to the EMMC and I ordered an already used EMMC from ali.