Main Site Documentation

Smoke


#1

Hi. I loaded a program into my Gadgeteer rover, and it generated a lot of smoke. Could you help me figure out what I did wrong?

:smiley:

But seriously, I blew up part of my rover yesterday, in dramatic fashion.

The highly interesting thing is that even though several gadgeteer cables themselves all burnt out their 1st wire, the modules that were connected to those cables all seem to have survived…

The only module that seems to have been damaged is the USB Client power module. The cable between my Hub Ap5 and one power controller melted and blackened and left the pin 1 (or 10) wire completely exposed after generating a tone of smoke… but both the hub module and the motor control module seem fine. I’m really surprised. I would have expected the modules themselves to be damaged.

I’m not entirely sure what went wrong - I think there was a short between the two power wires of one of the motor controllers, at the terminal block. I’m not sure how this ended up damaging the power module, and not the modules and main board in between. Its a mystery!

But I had to reorder some power modules, and it gave me an excuse to order the fez cream, and some new relay modules too.


#2

Not really that big of a surprise. Anytime I’ve ever shorted something, the first thing to go is either the voltage regulator or one of the diodes around it in the power module. Don’t throw out the module. You can likely just replace the VR and/or any bulging diodes and it’ll be good to go again. Extras are definitely a necessity, though, when doing this type of tinkering. Glad to hear nothing else was damaged, though!


#3

For this very reason I use a bench power supply with current limiting to power up any device I am working with during development. Only once the development is done and all is working do I switch to using a different power supply.

A good dual output bench supply is not cheap but neither is blown up modules etc. It’s well worth the costs to me in instances like this.


#4

Many under estimate the importance of current limiting power supply.


#5

@ Gus - Hey if you want to stick a brainpad in my order, for free beta testing by my son, I wouldnt object. :smiley:

I couldnt afford both the Fez Cream AND the Brainpad… and my son lost out on this conflict (I am a bad father, I know)

Maybe if you have any cosmetically challenged/unsellable ones laying around :smiley:


#6

Any tips on a good value bench supply? My ATX based supply recently stopped working and I’ve been thinking of doing an “upgrade”.


#7

If you can find the TTi PL330QMD on eBay I would recommend it. I have one that is over 12 years old and still in perfect working order.

The great thing with these is that you can set the current without unplugging your device as there is an OUTPUT ON/OFF switch as well as a main power switch. They show the current limit value with the output switch in the off position.

The replacements for this discontinued model are expensive.

Most of the other bench supplies only have an ON/OFF so you need to have an external method to power on and off your connected device. I use a push button ON/OFF switch for this type of supply as then I can set the current limit beforehand but don’t have the luxury of showing it.


#8

[quote=“ianlee74. Don’t throw out the module. You can likely just replace the VR and/or any bulging diodes and it’ll be good to go again. [/quote”]

Would that be the small IC labeled ZLDO 17-33 at IC7?

And if so, is this a suitable replacement:
http://www.aliexpress.com/item/50-pcs-x-AMS1117-3-3V-1A-Voltage-Regulator-AMS1117-3-3-LDO-SOT-223-AMS1117/32309885333.html

or this

http://www.ti.com/product/tlv1117-33?CMP=AFC-conv_SF_SEP


#9

@ mtylerjr - this appears to be the part that GHI is using. I would replace it with the same (and pick up a few extras while you’re ordering).

http://www.digikey.com/product-detail/en/LM1117MPX-3.3%2FNOPB/LM1117MPX-3.3%2FNOPBCT-ND/1010516


#10

GHI really needs to start selling vials of the magic smoke, it’s a pain to have to buy a whole new module just because the included magic smoke escaped. :stuck_out_tongue:


#11

Lets also be clear here - there’s actually not a problem here, GHI modules are rock solid.

I can count the failed devices I’ve had on less than one hand, in fact on one finger of one hand, and that one failure was because of my power supply (a 12v car battery charger, that I managed to short out while it was powering a small motor, that sacrificed a Cerberus)


#12

Oh… yeah. I want to stress that too.

This was user error (my fault) wiring up stuff, and directly connecting my massive 11.7v Lipo battery to the motor controllers, and not wiring it very well, causing a short.

I fully expected to have destroyed several modules, including the motor controller and Hub AP5 module that was attached, and possibly my Raptor… but all survived, and seem to have suffered no ill effects, even using the same sockets that were used.

The only casualty besides the power module were some cables - thats where the smoke came from… the power pin on the cables burnt off all the coating due to the short in my wiring.

I even thought about salvaging the burnt cables, cutting them in half, in case I needed some breakout wires for a socket and didnt need that particular pin, but then I realized I was just hoarding parts for the sake of hoarding… “Maybe this will come in handy some day” - a habit I really need to break. I need to get away from “Oh, you are throwing that VCR away? Well… let me open it up, and save all the tiny screws, big capacitors, socket connectors and led display modules I can get out of it before you do”… it’s an illness :slight_smile:


#13

Damn, I seem to suffer from this same illness as you. It must be contagious! :slight_smile:

I would bet that close to 100% of the folks in this forum suffer from this very same illness.


#14

You would win that bet in my case. I was throwing out an old MIDI/Audio interface, and felt the need for some relaxation, so I pulled the PCB out of the case and used my hot air station to pull out the pots, connectors, and LEDs. Never know when I might need some MIDI or audio jacks, and you can never have too many pots. :slight_smile:


#15

“Don’t throw that out! It has a perfectly good switch in it!” has become a running punchline around me.

It’s a proud tradition. My dad still uses a shoe-repair anvil that my grandfather made at the foundry where he worked, made out of a piece of old iron railway. He has the tools my grandfather used, repaired, used, and repaired again. Tearing apart hardware is the last bastion of the repair, recycle, reuse ethos, and given the toxicity of some of that stuff, better that it sit in my little boxes waiting for a new assignment or for the next maker-faire flea market, than in some landfill.


#16

@ mcalsyn - Yeah, I can identify with that. I still have my late father’s Simpson meter. I don’t think it works any more, but it’s such a classic piece of equipment, I don’t know that I can let it go. And I noticed the neighbors had a bike out for the trash, and was very tempted to grab it just for the sake of what I could possibly build from the parts. If I had more time, I probably would’ve succumbed to the temptation.


#17

Okay… I see that I am not unique in this quality :slight_smile:

We really need a community swap-section, where we all list our piles of old random bits and boards and see if anyone wants to swap something else for them.


#18

I like this idea and I bet my wife will to if I told her I would be getting rid of a lot of the stuff I have hoarded. I’d of course neglect to inform her that it would be a swap and more junk would replace it. :whistle:


#19

I have a bunch of random stuff, but no money - we need to consider the idea of a swap section again :smiley: