Question RVL-PSU (2 of 'em) might be borked. Custom Regulators: Stepdown boards vs roll-my-own?

[Morklympious]

So a bit of context, as I'm new here! I'm trying to essentially make my own version of a wii micro / nano / smol

I finally got around to wiring up a USBC power supply to power my regulator board (I luckily had two RVL-PSUs I held out from the store days) but when I wired everything up and checked the voltage, I got 5v of output from this usb-c breakout board, which is fine for me for just testing stuff, I suppose. I knew I needed more than 5v because it seemed like such a low number in my head.




Anyways, I'm running along the pads in the RVL-PSU and I clock 1v, 1.5v, 3.3v, and then I get to 5v. No reading. It just gives me a big ol' 0 on voltage readings.
So I start thinking why that might be. I had the thought that maybe the input voltage isn't high enough and the 5v just isn't drawing power because of it?

So I get some more boards that guarantee I get 20v from my power supply.
I'm using one of these boards to negotiate 20v of power from my usb-c power source onto the RVL-PSU, with (+) mapping to v-in and (-) mapping to GND.
I can verify I'm getting 20 volts, I can also verify I'm still getting the other stepped down voltages listed above. but 5 is still busted.



I would say "okay yeah the board is broken", but I had a SECOND RVL-PSU and the same thing happened. It seems unlikely that'd just happen to two boards like that, but also I'm not unwilling to believe that 5v is just dead, and I know I can still use the board, I think I just may have to get 5v elsewhere.

Which brings me to my next question: Can I just use any stepdown converter board if I don't want to build a regulator myself? It seems like everyone swears by PTH8080 + resistors (and probably for good reason, I don't doubt) but all of those materials seem like they have an inhuman lead time. Is it okay to use a stepdown as long as it supports stepping a voltage down to 1, 1.5, 3.3, and 5? Just curious about the conventional wisdom here.

Thank you!

 

[Wesk]

So I get some more boards that guarantee I get 20v from my power supply.
I'm using one of these boards to negotiate 20v of power from my usb-c power source onto the RVL-PSU, with (+) mapping to v-in and (-) mapping to GND.
I can verify I'm getting 20 volts, I can also verify I'm still getting the other stepped down voltages listed above. but 5 is still busted.

First of all, 20v is out of spec for the RVL PSU.

Specifications: Vin (Min): 5V Vin (Max): 17V

Second, the 5v regulator may be busted. I've had an RVL PSU in the past have multiple dud regulators.

[EDIT]

I can see your issue, you've not bridged the pads for the 5v reg to enable it.

 

[Morklympious]

First of all, 20v is out of spec for the RVL PSU.

Specifications: Vin (Min): 5V Vin (Max): 17V

Second, the 5v regulator may be busted. I've had an RVL PSU in the past have multiple dud regulators.

[EDIT]

I can see your issue, you've not bridged the pads for the 5v reg to enable it.

Okay well, two things in this case:

1) Thank you so much for letting me know about the spec range, I bought these a long time ago when I was really idealistic about getting it all done
2) Thank you for letting me know I had to BRIDGE THAT SMALL THING WITH A BLOB OF SOLDER. I began looking at that piece there with some curiousity like "did... someone scratch the board and now it's shorting here?"

I knew including pictures was the right move. THANK YOU WESK YOU'VE SAVED MY LIFE.

 

[Stitches]

Also if you end up using 5v as the input voltage, you don't need the 5v reg because you already have 5v coming in. It's why the 5v jumper is there

 

[Morklympious]

Also if you end up using 5v as the input voltage, you don't need the 5v reg because you already have 5v coming in. It's why the 5v jumper is there

This... makes a lot of sense. I would just wire from my input board in that case instead of the RVL-PSU, yeah. I had not considered that!
Thanks for that insight! I'm having a cascading sequence of "aha" moments and it's honestly super exciting.