Help pls from Technicians specially. About Generic Adaptors and Polarity Symbols

[Ninjek]

Question po 

I just can't seem to get my generic adaptors to work with most of my electronic stuff (mostly midi gadgets, module, drum machine, synth).

Every gadget of course, has a symbol that says kung ilang Volts, mA, and yung polarity niya if positive or negative. So i make the necessary changes dun sa generic adaptor. but when i plug it in, wala namang nangyayari. I have a feeling i got the polarity wrong (baliktad siguro pagkabasa ko), but i'm not sure if i should try the opposite polarity kasi sabi sakin masusunog daw yung loob nung gadget.

correct me if this is wrong, it's how i determine polarity of the gadget. it's from wiki



for example, my drum machine says "negative polarity" and "9v" when i base it on this diagram. even if i put the switch on the adaptor on the "-" and "9v" signs, walang nangyayari...

Another possible reason for this is that the drum machine says 300mA and my generic adaptor is 500mA, pero ang alam ko ok lang naman yun eh...

any help would be greatly appreciated

thanks!

[KitC]

Some equipment will not accept unregulated power supplies. I've even seen some electronic gear that will not function unless the adaptors were full wave rectification with filtered outputs.

[3650guy]

...500 mA means that it can supply up to 500mA. it doesnt mean that as soon as you plug it in, 500mA will be immediately supplied to the connected device. it will only give out what is needed by the device circuitry.  it is better to have a higher rating than the device itself. but using a 2amp or 1.5amp on a low current device would be wasting some energy.

most electronic circuitry (not sure about boss pedals) will have a diode in series, after the DC plug to prevent that dreaded "reverse polarity" mishap. because of those universal adaptors whose polarity can be switched. but it is better to double check first before powerring up any DC device.

[Ninjek]

Some equipment will not accept unregulated power supplies. I've even seen some electronic gear that will not function unless the adaptors were full wave rectification with filtered outputs.

oh so it's really possible na i'm not doing anything wrong, talagang hindi lang pwede yung generic adaptor sa zoom drum machine ko? awwww.... 

  thanks sir kit! 

[Ninjek]

...500 mA means that it can supply up to 500mA. it doesnt mean that as soon as you plug it in, 500mA will be immediately supplied to the connected device. it will only give out what is needed by the device circuitry.  it is better to have a higher rating than the device itself. but using a 2amp or 1.5amp on a low current device would be wasting some energy.

most electronic circuitry (not sure about boss pedals) will have a diode in series, after the DC plug to prevent that dreaded "reverse polarity" mishap. because of those universal adaptors whose polarity can be switched. but it is better to double check first before powerring up any DC device.

thanks for the info about the mA, that would surely help in the future as well. actually, dati nung d ko pa masyado gets yung polarity symbols, sinusubukan ko lang iswitch yung polarity symbol ng adaptor hanggang sa gumana na. i don't know if i was just lucky, pero wala pa naman akong nasirang gamit because of that. hindi gumana sa negative, so ginawa kong positive yung polarity, tapos yun gumana na. no damage naman... now that i'm aware of the polarity stuff, nakakatakot nang subuk-subukan 

[peeves24]

oh so it's really possible na i'm not doing anything wrong, talagang hindi lang pwede yung generic adaptor sa zoom drum machine ko? awwww.... 

  thanks sir kit! 

yikes...some digital effects units/drum machines accept AC voltage and not DC!

check mo maigi yung nakalagay sa manual baka 9volts/15volts AC lang ang hanap nung zoom mo. kung ganun, imodify mo yung generic adaptor mo at kalasin lahat ng parts except yung transformer. polarity doesnt matter kung AC nga ang kailangan