Help! can power supplies just... Die??

[Coley]

ok, this has happened to me with two different adapters and is really starting to concern me.

they have both been the multi-adapter universal-voltage kind from radioshack/ wal mart, and plugged into a daisey chain

at first they work fine. then all of a sudden, one day i'll come to play and it doesnt power anything up.

is it possible that these things jus die??? am i doing something wrong??

they cost like $15 a piece so i can't just keep buying them.. and i need them to work!

any ideas what's going wrong? or is there a chance they still work, but just went out temporarily??

BTW, if it helps any- they've been plugged into power strips that my amp and computer are plugged into as well. I've gone around the house the adapter in  other various outlets and it still doesnt work

[Peter Snowberg]

and plugged into a daisey chain

Do you now how much current you are pulling out? That adapter may be listing a current rating based on its lowest voltage setting. You might just be burning it out with overcurrent.

If you are using 9VDC, I would get a nice, healthy 9 volt DC adapter. They'll be cheaper and will probably last a lot longer. A 1 amp adapter is pretty common and it will power a LOT of effects.

Good luck!

-Peter

[Mike Burgundy]

they can "just" die, anything can (old age/production weakness/fluke).
It is common sense to make sure there is absolutely no reason whatsoever for the adapter to die (it doesn't happen often).
Losing two in a row suggests there IS a reason: drawing too much current comes to mind.

[gez]

Paying a little extra for something that allows you to change a fuse will probably save you money in the long run.  My Boss adapter allows for this and I'm very grateful for it!  I know that this isn't your problem, but it's worth considering anyway (seeing as you're going to have to buy a new one) as It's so easy to accidentally short the supply when breadboarding, I do it a few times a year on average.  

gez

[RDV]

they have both been the multi-adapter universal-voltage kind from radioshack/ wal mart, and plugged into a daisey chain

at first they work fine. then all of a sudden, one day i'll come to play and it doesnt power anything up.

is it possible that these things jus die??? am i doing something wrong??

I have always had to break those open after a while and cut a couple of inches off the wire and re-attach, they break where the wire goes in. They're cheaply made. I've never had to do this with a Boss adaptor.

Regards

RDV

[Coley]

hi, can you explain that again?? there's a way for me to fix it?

[Mike Burgundy]

*if* it's a break in one of the connecting wires, yes. You'll have to open up the adapter and do some measurements to see what exactly has failed.
Start here:
-primary side of transformer conducts?
-secondary conducts?
-primary to secondary does not conduct/open connection?
-visibly burnt/broken/bloated parts?
plug it in. Watch it - lethal voltage present.
-AC input present (lethal, watch it!!) at primary side of the transformer?
-AC ouptput voltage present at secondary side?
-DC present after rectifier?
-DC present at output?

Most probable faults are broken wires/blown diodes/blown transformers/blown caps. In that order, more or less. If anything is blown, it usually is for a reason, remember that!

[Coley]

thanks. but since its not too much money to replace it, i think it's well worth it just to buy a new better one, and not play around with high currents, being that i have little knowlege about all that.

so... what could i be doing wrong? the adapters i was using were around 700 ma total and 1000 ma total. would that be the problem?

say i'm going to be running about 2-5 effects total with this... what kind of (relatively inexpensive) adapter should i buy that will work well and not break? the boss psa? one of those 1-spot adapters?

thanks,
coley

[Mike Burgundy]

it really depends on the effects you are running. 5 distortions should probably be fine, 5 digital delays will probably fry that adapter.
Try to find out what the required current for each pedal is. If you have that, you can make sure you're not simply frying the poor adapter.
Next, see if there are any weak spots or high-risk areas in the connecting cables - can/does it get stuck anywhere in a flightcase, any weird corners opr twists, etc.
If you just keep replacing adapters, but DO have a problem, you're going to need one heck of a lot of adapters.
On the other hand, you will have made a new friend. Who happens to sell adapters

[Coley]

ok well i was running:

Morley Wah
Danelectro PB J delay


i THINK that was all...

and with a 9v 1000ma adapter




do you think the 1000ma was too large for just the two pedals?

[Mike Burgundy]

I don't (although I don't own those pedals nor have manuals or datasheets on them - do a search). Might be a different p[roblem as stated: mechanical, perhaps one of the pedals has a bit of a short - not enough to kill the lot instantly, but still drawing considerable current.
Have a look. A 1 Amp 9V should be ok, I think (check that!)

Actually, I just realised the question was the wrong way 'round. Rephrase: I don't think 1A is too small for those two pedals.

[Andy]

I'll buy your adapters from you.  I might could fix them.  What would you take for them?  email me if interested.

[SoundTech]

do you think the 1000ma was too large for just the two pedals?

No.  See, the adapter had 1000mA, or 1A, of current available to the pedals.  That doesn't mean it was forcing 1000mA on the pedals.  The pedals will draw what current they need.  So, you want to have as much or more current available at the adapter as the pedals need.

[RickL]

Remember that the outside of the barrel of these adaptors is at the positive voltage (assuming they are negative tip like most pedals require). If anything at ground touches the barrel (i.e. the metal barrel of a patch cord or the outside of a metal 90 degree patch cord) it will short the positive supply to ground and probably burn out the secondary of the transformer in the adaptor.

A burned secondary has already been mentioned as a posibility, I just suggest this as a reason why it might happen for "no reason". How many adaptors did I fry before I figured this out you may ask?  :oops:

[Paul Perry (Frostwave)]

yes, it is always a good idea to plug all the fx boxes in, BEFORE turning on the power. Because, then you can't accidentally short any plugs out!
And, as an earlier poster suggested, if your meter shows open circuit on the mains input, either a fuse or the primary is gone, and it's all over (it isn't legal at least in Australia to have a replacable fuse in a plugpack!)

[Mike Burgundy]

It's not legal to have a fuse in a plugpack? I wonder why?
Come to thing of it, it's not done her eeither though I don't know if it's regulated by law..
What could be the reasoning behind this?

[gez]

I don't think it's mandatory to have fuses in mains adaptors here in the UK either.  So long as there's no danger of a customer being fried then a manufacturer doesn't have to fit one.  The reason they don't, I suppose, is that it's cheaper.

Before I knew anything about electronics (do I now?) I tried to mod a LPB to run off the mains using a metal jack.  After frying one transformer I wondered if it was anything to do with the mod I'd just done or whether it was just coincidence, so I plugged in another.  Three fried transformers later I decided to go to my library and learn a bit about electronics...

[Paul Perry (Frostwave)]

What I said was, you can't have a REPLACABLE fuse in a plugpack here. You have to have one, so that if you short the output, the extra current blows the fuse & the house doesn't burn down. And, you can't then replace it wiht 8 gauge copper wire... damn!

[gez]

I meant replaceable fuse too - sorry for any confusion!