Guess there's a reason this power supply was so cheap...

Started by Scruffie, March 25, 2014, 01:17:04 PM

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Scruffie

Just working on a 12V 5840 overdrive, all set up fine on the breadboard and working happily... the input jack wire came loose though and I was just putting it back when *BANG*

Here's the power supply in the wall...



and here's the rest of it about a metre away from the wall...



Supposedly it was meant to deliver 1A, so it shouldn't have been struggling to power anything and nothing was even close enough to short, sufficed to say it made me jump a little  :D

gjcamann


Jdansti

That was one if those audible fuses. It's a feature. ;)
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Scruffie

Quote from: Jdansti on March 25, 2014, 03:03:12 PM
That was one if those audible fuses. It's a feature. ;)
:icon_mrgreen: of course! How foolish of me, also one of those 'nearly smacked in the face with the power supply' to let you really know it needs attention.

I guess I did get a 1N4007 out of it... that blew clean out the circuit board without a mark.

Jdansti

It might be worth a little forensics to make sure you don't damage another supply.   I wonder if it was only the diode that blew, and when it did, it mechanically took out the fuse.  Was the diode on the primary side of the transformer or after the regulator? 
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R.G. Keene: EXPECT there to be errors, and defeat them...

Scruffie

Not sure I want to investigate an SMPS power supply that just exploded... seems a tad dangerous.

Think i'll just avoid £3 supplies and get a decent transformer based one, i'm now powering the heaters from my 300mA 12V supply and the plates from another one and it's fine, no warm transformer, nothing going bang.

Jdansti

You definitely don't want to plug it in again! :icon_eek: Your probably OK if the replacement supply is working fine.
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R.G. Keene: EXPECT there to be errors, and defeat them...

Scruffie

Quote from: Jdansti on March 25, 2014, 04:39:18 PM
You definitely don't want to plug it in again! :icon_eek: Your probably OK if the replacement supply is working fine.
There's not a lot to plug in! Haha, a plug with 2 wires hanging out does not a power supply make.

It is although i'm a little nervous of it happening again anyway lol, looking in to something a bit more 'permanent' preferably with an explosion protection circuit.

duck_arse

are they dobs of ex-molten metal on the white mains switch? nice.
don't make me draw another line.

GibsonGM

Look on the bright side - you've got  a really cool LED out of the deal, lightly used and ready to put in a pedal!!    ;o)
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Scruffie

Quote from: duck_arse on March 26, 2014, 11:36:31 AM
are they dobs of ex-molten metal on the white mains switch? nice.
Plastic but still!

Quote from: GibsonGM on March 26, 2014, 04:54:47 PM
Look on the bright side - you've got  a really cool LED out of the deal, lightly used and ready to put in a pedal!!    ;o)
:icon_lol: yayyy, I wonder if it survived.

duck_arse

it's taken me until today to realise, what you have there is a "burst box".

I'm surprised jd missed it.
don't make me draw another line.

petey twofinger

got an "energizer" battery charger with a wall wart marked 16v 6 a yesterday for 1.99 at good will , it honestly looked brand new . plugged it in , the meter read 13.3 , i go "huh" smoke starts SCREACHING out the thing .... it may be called magic smoke , but the aroma is far from enchanting ... best part , they take returns with reciept . i cut the cable ( keeping that for my trouble ) just to be safe :)
im learning , we'll thats what i keep telling myself

duck_arse

don't make me draw another line.

Jdansti

Quote from: duck_arse on March 28, 2014, 11:10:56 AM
it's taken me until today to realise, what you have there is a "burst box".

I'm surprised jd missed it.

Dang!  ;D
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boogietone

An oxymoron - clean transistor boost.