Is this dc adapter safe to plug into my keyboard instrument

[computer-joe]

I bought a keyboard instrument years ago, and it uses 6 aa batteries, i don't want to keep charging the batteries, so instead i want to plug it in

In the back of the keyboard there is a plug-in for the dv adapter, right below the plug "DC 9v"

So i looked in my old boxes and i found an old adapter from my old router and the adapter says:
Switching Adapter
Input: 100-120v~50/60hz 0.3A
Output: +9V _____ 1A
-- -- --
Level 3


Is it safe to plug this into my keyboard even thought it came with my old router

9v should work with 9v right?



also, another question, what would happen if i plugged in a 5v(lower), or 13v(higher) than what it takes

thanks!

 

[(*steve*)]

The 9V adapter may be ok.

What's does it say near the power socket?

Make very sure the polarity is correct.

 

[computer-joe]

Where exactly do you mean, where is the power socket

you mean the wall? its a normal north american power outlet, there is nothing written on it

 

[computer-joe]

I plugged it in and nothing happend!



i looked in the manual and it says i should use a
AC Adapter AD-5,
9V ______ 7.7W
-- -- --


my router adapter doesnt say W, it has A,
does this mean that the v is correct, but it needs an A

the router adapter is a 1A, and in the manual it says use 7.7w

why does it says a and not w, how many watts is 1amp
im guessing it's not even 1 watts,

thats probably why it doesnt work



i think i have a 12v adapter with 10w, is it safe ? or will it blow up my keyboard and burn down my house

 

[kellys_eye]

9V at 7.7W is approximately 0.8A so your 1A adapter is rated ok for such use.

Check that the power plug (barrel plug) is the correct size - quite often the centre pins are different and if you use a larger barrel on a thinner pin they don't touch and power won't flow.

 

[BobK]

Show us a photo of the power jack on the keyboard, and one of the adapter. Both should have a polarity indicator. It is quite possible that the polarity is backwards, and you might have damaged the keyboard if it was not designed with protection for reverse polarity. Does the keyboard still work on battery power? If so, you are lucky.

Bob

 

[Terry01]

Hey kellys eye and Bob......I predict more burst fuses! Lol

 

[computer-joe]

It is still working, i charged some batteries, and it still powers up, so i didn't fry it


Here are the photos,

 

[BobK]

Yep, the polarity is reversed. And I don't think the plug is right, it looks to me like the inner connector on jack (keyboard) is smaller than the inner connector on the plug (power supply) Do you have a vernier caliper?

To get this to work you need to get the correct plug and rewire it to the adapter.

Do you have a vernier caliper?

Bob

 

[kellys_eye]

so i didn't fry it

...luckily! The smaller centre pin potentially saved the day by failing to make contact!

 

[computer-joe]

so thats what those circle things are for, polarity, i didn't know that and i never payed attention to them before until now

I do not have a vernier caliper,

you mean cut the end of the adapter off, and buy a correct size and then open up the adapter and rewire it?

i don't really want to mess around with electricity,

the adapters are about 5 dollars on ebay, from china


i am glad i didnt fry it, i would of been sad

 

[BobK]

Okay, assuming you can get the correct one.

Bob

 

[kellys_eye]

Centre-negative is a known 'b*tch' in the industry - often only used where the socket is 'switched' and allows for change-over from internal batteries to external DC source - just as you have!

You could do a quick check by snipping the wires to the plug (leave a few inches of cable so you can rewire) then simply reverse the wires, twisting them together, then insulating with tape.

This 'slap-dash' method will allow you to try the plug again - this time with the correct polarity - and some jiggling of the plug may get you a temporary contact for long enough to prove the principle. Thereafter get the right plug and/or a suitable power pack with plug fitted (which won't be as easy as it sounds given that the majority now have centre-pin positive plugs).

You CAN get power packs that allow you to fit a selection of plugs (supplied with them) and also allow for reversal of the plug polarity simply by fitting it arse-about-face in the socket they supply. Usually go under the name 'universal power pack' or somesuch name.....

here's a typical example

http://www.ebay.co.uk/itm/9v-20v-Un...hash=item4d32769375:m:m2p44dmmYTo3FzxR9MPiLhw