I removed the regulator to revive a Photon

I had two Photons that I thought were just trash since I had burnt something and saw smoke and then every time I powered it up, it heated like dangerously bad so I stopped using them, until yesterday that I read about physically removing the regulator and to my surprise it worked (after removing the regulator and connecting the Pins of 3v3 and VIN).

I am a complete noob so I would be appreciated if some few points are made clear to me:

  1. why does this setup (regulator-less Photon) only works when 3v3 and VIN are connected?

  2. nothing bad happens if I connect the two GND pins right?

  3. I have been able to power up them via microUSB (from laptop and wall cellphone charger) and from wall cellphone charger but with a split wire of (+) and (-) where I connect it to Photon (to the 3v3 and VIN since I have connected these pins at all times). This leads to the questions:

3.A) I noticed that my wall cellphone “TURBO” charger but with split wire of (+) and (-), would not work and Photon D7 and main-led will blink blue and White respectively (I had a NeoPixel connected but this is probably unrelated, but don’t want to connect again like this without the NeoPixel to see if that was the problem as I doubt it), but my non “TURBO” charger with same setup works, what is happening here why TURBO charger is bad?

  1. in the case I power from microUSB, do I get 3v or 5v output on my 3V3 and VIN pins (remembering that they are connected)? Or does this depend if I am plugged to the wall or to a Laptop?

  2. are there risks to use this Photon without its integrated regulator, if so, which ones?

thanks, I hope most of the questions are basic enough for the knowledged and I appreciate any time put in answering this, might help to not burn the Photon dead or start a fire in my room o.o

If you really removed the regulator you would not need to connect the Vin pin as it is then isolated from the rest of the board :wink:

See here

And you must not feed more than 3.3V into the 3v3 pin.

1 Like

ok this is really helpful, some bases not to just go blindly connecting stuff around hehe, thanks will keep in mind

so basically I will stop completely trying to power it up using wires to the 3V3 pin unless I can get a 3.3V regulator (which anyone should do I have read, even with an unmodified Photon)… so I will use microUSB from now however, will that be safe for my regulated-less Photon?

How will the Photon will regulate those 5V from microUSB?

When you look at the block diagram you’ll see that V+ USB (coming via the microUSB receptacle) and the Vin pin are both feeding into the regulator which puts out 3.3V for the system.

Consequently, with that regulator gone V+ USB and Vin are not connected to the rest of the board at all.
And hence this …

… is not possible (but safe as it won’t power anything :wink: )

wait but I have 2 different Photons that work via microUSB that I physically removed something, but you tell me that is impossible? weird mm, I will put a screeshot with the component I physically removed (maybe is not the regulator?).

I think I know what’s going on, even if VIN and the microUSB are no longer connected to anything, when I connect the VIN to 3V3 I’m effectively connecting the 5V from my Laptop to the 3V3 pin to power the Photon up (which is bad right? I should put VIN to a 3.3V regulator, then back to the 3V3).

Yup, that is the regulator, but as you can see here with that component gone entirely this should in deed not work

Could it be that you have some solder bridges on some of the pads?

Correct, this is bad and you should definitely not do that.

Having an off-board 3.3V converter and then feed that to 3v3 is the way to go when you cannot replace the original component.

Ok it was a good idea to post this, I now learned a thing or two, and most importantly keeping everything safe.

My final setup once I have the 3.3V regulator will be: microUSB (5V either from Laptop or Wall cellphone charger) to Photon, VIM to 3.3V regulator, 3.3V regulator to 3V3.

Thanks for all the help, will get that component asap. :smile:

1 Like

I have blown a couple of these regulators myself and I got tired of feeding 3.3V.
I looked for the RT8008 and I could not find anyone selling the 3.3V version. I am not sure if the one on amazon is the real thing and I didn’t want 20 of them (https://www.amazon.com/20PCS-RT8008-33GB-BUCK-SOT23-5-RT8008/dp/B01CCPXKSY). Also look for SP6669 by MaxLinear and ST1S12XX by ST. They seem to be drop-in equivalents, but nowhere for sale.

While searching for the 8008, the LM3671 came up. It’s not a drop-in, but it’s the closest one specs-wise.
Here is a close-up of what I did.

If you feel bold enough to attempt this, at your own risk, I can send you rework instructions.

I wouldn’t attempt that weld as I don’t know how to nor have proper tools and for a bunch of reasons, but I find it fine to just have it next to it on a protoboard.

But good stuff, I don’t really know how to read the specs very well, I think what I need is just that is a fixed voltage of 3.3V (I think they use the term “linear regulator” for this?) and also at least 0.5 A (I think I 1 or 1.5 is fine?) but really I am just blindly trusting anything I see and will try to buy, since you are right, not easy to find in stores (the one I went only had 5V regulators), so if you don’t mind, I will carelessly add those bunch of component names to my list and hopefully stumble with one of them.

I won’t connect anything intense to my Photon, actually it will just be a NeoPixel led, and my area is really coding and the projects I will do will not really have anything connected to the Photon, so maybe any 3.3V regulator I find will suffice? Is not that I need to dissipate exceeding heat or anything else (I don’t really know what I’m talking about, but I read about some people burning regulators because they didn’t put transistors? or something, well I’m sure I don’t need to worry about this do I? I am just connecting a shiny led that blinks in multiple colors hehe).

Those components would need soldering as well. The separate 3.3V regulator would be the faster approach. There are many on Amazon that take 5V in and put out 3.3V, but you would have to add wires to the wall charger. This one has a micro USB input, but it’s a bit of an overkill and pricey.

I have a wallcharger with an USB that I split their wires and carefully isolated + merged with Jumper-wires with black tape. But I think I can use the VIM after connecting the microUSB, I have been told those 2 are no longer tied to the Photon at all, but yea I have that covered in how to get a (+) wire of 5V to put into the regulator safely, don’t worry.

1 Like

The RT8008 is not a linear regulator but a step-down buck converter.
But if you were OK with a linear regulator (which just dissipates the access voltage) for a short term workaround you could use your 5V source with a voltage divider.