Do wall warts go bad eventually? Or is it old caps?

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soundchaser59

Reluctant Commander
What about those ubiquitous 9v wall wart adapters??

Do they go bad? Do they eventually wear out and start adding in hum and buzz? Or is it just a transformer that lasts forever??

Someone suggested that it might be old capacitors in the power supply causing hum in an old fx unit, not bad pots.

So I'm tempted, should I do an experiment and start replacing caps? Or just get a new super clean 9v adapter??
 
soundchaser59 said:
What about those ubiquitous 9v wall wart adapters??

Do they go bad? Do they eventually wear out and start adding in hum and buzz? Or is it just a transformer that lasts forever??

Someone suggested that it might be old capacitors in the power supply causing hum in an old fx unit, not bad pots.

So I'm tempted, should I do an experiment and start replacing caps? Or just get a new super clean 9v adapter??
Click to expand...

Well, bad pots generally don't cause hum, they usually cause crackle.
Bad PS filter caps can definitely cause hum, as can a bad wallwart. I'd start by checking if a new wall wart solves your prob, since that's the easy step.
 
New wall wart made no difference.

I'm waiting for the rainy day when I'm bored silly and I'm wondering if my soldering iron still works...... grab a bag full of caps....make coffee..... etc..etc.... Just might end up with a $10 dollar "refurbished" Midiverb.
 
Did the unit just start making noise ? Have you moved it to a different location like next to a different rack unit. Are you sure the noise is limited to just the fx unit? I ask because sometimes you can get some interference type noise from modules being too close. Before you go potentially making a doorstop I would make sure that all your grounding is in order too if you haven't done this already.
 
wall warts do go bad.... they sedom (cant bring myself to say never)cause humm...hum ALMOST ALWAYS is caused by bad filter caps or ground problems... was pro tech for 20 yrs... thats what my experience has been wall warts when they die usually open(as oposed to short) as a result of too much current drain... (from age or bad filter caps see a conection here?) try to avoid going crazy with the replacement caps 1.5-2x the original capacitance is ok as for voltage anything again 1.5 -2xs as a rule more than that isd a waste also becareful with the tollarences as supply caps can be asmuch as -50/+20 %... (really 1/2 of rated capacitence is not uncommon especially for higher voltage stuff like guitar amps)
 
BTW ... ya may want to replace the voltage regulators while your at it .... in more consumer oriented equip not unusuall if its just a zener diode.... good luck
 
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