Beware cheap breadboard power supplies, incinerated my Teensy 4.0!

C

CRC

Well-known member
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I handn't used this before and thought it would be handy since I had a 12v barrell type supply already nearby. I hooked up the Teensy and plugged it in. The cliche time slowed down thing happened as I watched the Teensy's red LED glow bright then slowly die as a puff of smoke wafted up from underneath the rows of header pins.

I checked the voltage and for whatever reason the regulator failed propagating the full 12 volts right into the 5v rail on my breadboard and into the Teensy.

Just a friendly reminder from my failure to always check voltages first, especially if you haven't used a supply before.

I have plenty of time to reflect on my failure as Teensy 4.0s are unobtainium.

:mad:
 
Wow!, so sorry this happened but like a lot of complete junk from Asian countries being sold on ebay and elsewhere you always have to be careful. In my case the regulator was not even a regulator, it passed the 12 volt straight on through and fried everything on the bread board. I fried the T3.5 this way and ever since I have never ever had a problem. I took a 600 watt ATX power supply and converted it to a board power supply so now I have an unreal power supply for 3.3, 5 and 12 volts with more amps then I will ever need. I have a volt meter on each line to tell me exactly what my 3.3, 5 and 12 volt line are at all the time. Plus you can't get better than a name brand power supply regulation that is completely stable but just in case I have fuses on each line output.

Please do your self a favor and do this you will never regret it especially if you do a lot of projects like I do. Gut the board you have now and solder the lines from the ATX power supply 5 and 3.3 volt lines and never need another power supply the rest of your life lol! You can get the adapter boards on Ebay and Amazon (God I hate Jeff Bozo) but me being me made my own that handles twice the power than those anywhere.

Regards,
Marathonman
 
That is really a crime, doubly so these days - I have some from years back that look similar - seems I used one once and it worked.

@Marathonman: there is a feedback line from the motherboard to enable the power supply output? Was that the case there and if so: what line and what is the trigger? Saw it once and didn't keep track of it. Also do they need a base load of some amount to keep them stable?
 
Marathonman said:
I took a 600 watt ATX power supply and converted it to a board power supply so now I have an unreal power supply for 3.3, 5 and 12 volts with more amps then I will ever need
Click to expand...

Aren't there a couple of gotchas with using ATX PSUs like this though? For example, I think I read somewhere that most ATX supplies require a certain load on the 5V outputs before you can use the 12V ones? And using PWM when e.g. powering LED strips might cause problems for the power supply's decoupling capacitors? (I don't know if these points are true or not, I just recall having read things like this somewhere and as a result have been wary of using ATX PSUs for this sort of thing).
 
Marathonman said:
Wow!, so sorry this happened but like a lot of complete junk from Asian countries being sold on ebay and elsewhere you always have to be careful. In my case the regulator was not even a regulator, it passed the 12 volt straight on through and fried everything on the bread board. I fried the T3.5 this way and ever since I have never ever had a problem. I took a 600 watt ATX power supply and converted it to a board power supply so now I have an unreal power supply for 3.3, 5 and 12 volts with more amps then I will ever need. I have a volt meter on each line to tell me exactly what my 3.3, 5 and 12 volt line are at all the time. Plus you can't get better than a name brand power supply regulation that is completely stable but just in case I have fuses on each line output.

Please do your self a favor and do this you will never regret it especially if you do a lot of projects like I do. Gut the board you have now and solder the lines from the ATX power supply 5 and 3.3 volt lines and never need another power supply the rest of your life lol! You can get the adapter boards on Ebay and Amazon (God I hate Jeff Bozo) but me being me made my own that handles twice the power than those anywhere.

Regards,
Marathonman
Click to expand...

Thanks for the condolances or however that's spelled. I finally had to buckle under and buy one for about 3x the price.

As for the ATX PS, funny you mention that, I happened to have one of the ATX to 12, 5, 3.3 converter boards but haven't yet hooked it all up to make one of those. I was lazy and figured the little board would be more handy on the limited desk area I was working at. Live and learn I suppose. The next priority is to finish that ATX supply. I'm glad you mentioned it. I have some project boxes and some voltage display boards I can use to make a nice bench to supply.
 
Oh man that sucks, especially the scalper price for a replacement.

If you can still cancel that 3X priced order, email me directly and I'll find one we can sell at normal price.
 
@Marathonman: there is a feedback line from the motherboard to enable the power supply output? Was that the case there and if so: what line and what is the trigger? Saw it once and didn't keep track of it. Also do they need a base load of some amount to keep them stable?
Click to expand...

Yes Defrag all you say is needed and can be found on the net just google it. I used a 10 watt power resistor and I have no problem. Just be aware that some new ATX power supplies require the resistor to be on the 12 volt line not the 5 volt line like the older ones did.

CRC;
I was lazy and figured the little board would be more handy
Click to expand...
DUH!, then you got bit on the butt lol! So now that was good motivation to make a real power supply that will last lol!

ATX-Power-Connections.jpeg
ATX-Wiring-Diagram.jpeg

I went a little further and put voltage meters on all three lines to give me constant visual. Zener diodes can be put on the lines for further overvolt protection but is really not needed.

Regards,
Marathonman
 
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A little note: I wouldn't really use this - not for electronics that don't consume much power.
You're better off with a small power supply that has an overcurrent shutdown for normal tinkering. There you can set the estimated current demand beforehand and then have a reliable shutdown if something unplanned happens.

Something like this can also be added later, and also as a kit.

Frank.

p.s. in addition, current meters are useful.
 
And I'd add at least switches to each voltage as a (kind of) "panic / emergency" button for these high currents. You don't imagine how fast a thin wire can burn, in case of a short.
 
Haven't had a single problem with this power supply since I christened it. Besides if your that paranoid use the 5 or 12 volt rail with voltage regulators. I also have one lined up for many lithium cell charging off the 5 or 12 volt line which will be a lot of them like 20 at a time lol!
 
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