Solved Fun Voltage Problem

[LambBrainz]

So I've got an OMGWTF trim and a PMS-Lite. When I supply power to the PMS and turn it on, I get no voltage when measuring at the Wii. If I remove the 3.3V line, I get voltage at the wii and everything seems fine.

Things I've tried:
[1] Remove all wires except battery and fan. Did this and every voltage rail was fine
[2] Check resistances at Wii with no wires. Did this and everything was within range
[3] Tried wiring the 3.3V to a different cap. Normally you wire it to that empty pad to the left of the LDO, but you can also do the tantalum one above the GPU. Tried this one and it didn't work either
[4] Attach the 3.3V and remove another volt line. Did this and it still didn't work, so it's definitely seems to be the 3.3V

All of my wires are 22 gauge, I try and keep connections and lines short, as well as cleaning to prevent any flux connections. Anything else I can try?

One other thing that could affect it. There was one powerup where I had my bench power supply on a 2S equivalent setting (7.4V, ~2A). But after going back to 1S (~4.7V, 2A) everything seems fine and nothing seems destroyed

Wiring pics (ignore any grossness with the blue wire. I've tried several different places and this was my latest test

 

[CrazyGadget]

If you had 7.4V going into your B+ line, your PMS is definitely cooked. Hard to tell what exactly since nothing looks particularly smoked, but the PMS is designed to only be capable of a 1S input. Anything higher than that can and will lead to damage to the board (normally the BQ chip fries but it doesn't look fried here). Also, you need to wire batteries to the B+ pad, a bench PSU will not suffice. A single 18650 or 21700 is capable of powering the trim.

 

[LambBrainz]

If you had 7.4V going into your B+ line, your PMS is definitely cooked. Hard to tell what exactly since nothing looks particularly smoked, but the PMS is designed to only be capable of a 1S input. Anything higher than that can and will lead to damage to the board (normally the BQ chip fries but it doesn't look fried here). Also, you need to wire batteries to the B+ pad, a bench PSU will not suffice. A single 18650 or 21700 is capable of powering the trim.

Any guess as to which part is cooked? Cause when I power it on, every rail still has the correct output. I assume there's something that changes when there's an actual load on the other end?

Also curious why a bench supply wouldn't work. I've seen that before but I never really understood why that was the case

 

[LambBrainz]

Alright, got a new PMS Lite, wired it up: nothing

Remove the 3.3V connection, fan spins and the PMS starts putting out power however I'm not getting anything at the Wii.

Would this be a boot issue? Like should I try and resolder the U10 line a couple of times?

 

[Stitches]

Maybe the overvolt necked the Wii

 

[LambBrainz]

Man I hope you're wrong lol

What would be a good test for that? See if the CPU/GPU get warm?

 

[Stitches]

Nah, the chips will warm up when voltage passes through them regardless of whether they're functional or not

 

[LambBrainz]

Weirdly enough, I used an 18650 instead of my bench and it worked just fine. No idea why

I've talked to Gman before and he said that a bench supply *shouldn't* cause any problems (might get some voltage drop over the alligator clips) but otherwise should be fine.

Seems the fix was to use a battery

 

[Stitches]

Weirdly enough, I used an 18650 instead of my bench and it worked just fine. No idea why

I've talked to Gman before and he said that a bench supply *shouldn't* cause any problems (might get some voltage drop over the alligator clips) but otherwise should be fine.

Seems the fix was to use a battery

Ah, yeah that's a known issue. Sometimes the PMS boards just don't like fixed voltage supplies