AC Adapter dilemna (for the electronic illiterate)

[stankonia3000]

So I bought a scanline converter off the FS/FT forum, but it did not come with an AC-->DC Adapter. It takes 9V and draws 500mA of current, according to the user's manual.

So I go to the local, respectable electonics store and the lady shows me that all they have in the right "plug size" is 9V at 1A (1000mA) of current. She says the 1000mA is fine because my unit will only draw the necessary 500mA from it.

So I get home, promptly hook up the AC Adapter to the unit and plug it into the wall and....POP...I can tell that something fried immediately by the telltale smell and smoke wasping out from the inside of my scanline converter. So I bust out my Multimeter and see that the AC Adapter is actually outputting 13.4V and 3.4A of current.

I barely know anything about electonics, but does this sound right? Both the packaging and the label on the AC Adapter say 9V, 1A.

 

[dighn]

probalby a cheap adapter that doesn't have a proper voltage regulator so it outputs ~9v at 1a but higher voltage when the current draw is lower

or it's just defective

 

[MisterPresident]

dighn's probably right. I've learned to be very careful when using AC/DC adaptors, as I've had more than one incident with things going pop..... My cousin once plugged my 110v Nintendo into a 220v socket, because he found an adapter for it..... another time my sister tried resetting the cable modem and plugged the router plug into the modem and vice versa.

Also, you may want to contact the manufacturer of whatever it is that went pop to see if they will cover it under warranty, as I've had 2 Philips speaker systems that have fried.... when using the OEM ac/dc adapter! Luckily they were happy to replace it.

 

[RossGr]

Just curious, how did you measure voltage and current? What was drawing 3.4A? Was the 13.4V open circiut? Need more details on your measurements before anything can be said.

 

[FrustratedUser]

Originally posted by: RossGr
Just curious, how did you measure voltage and current? What was drawing 3.4A? Was the 13.4V open circiut? Need more details on your measurements before anything can be said.

I second that.

 

[dmcowen674]

Originally posted by: stankonia3000
So I bought a scanline converter off the FS/FT forum, but it did not come with an AC-->DC Adapter. It takes 9V and draws 500mA of current, according to the user's manual.

So I go to the local, respectable electonics store and the lady shows me that all they have in the right "plug size" is 9V at 1A (1000mA) of current. She says the 1000mA is fine because my unit will only draw the necessary 500mA from it.

So I get home, promptly hook up the AC Adapter to the unit and plug it into the wall and....POP...I can tell that something fried immediately by the telltale smell and smoke wasping out from the inside of my scanline converter. So I bust out my Multimeter and see that the AC Adapter is actually outputting 13.4V and 3.4A of current.

I barely know anything about electonics, but does this sound right? Both the packaging and the label on the AC Adapter say 9V, 1A.

The unit should've been fine with the little extra voltage, most likely the polarity on the plug was backwards. There should be a fuse in your scanline that could be replaced, change the polarity on the adapter plug and you should be good to go.

 

[Linux23]

Originally posted by: FrustratedUser

Originally posted by: RossGr
Just curious, how did you measure voltage and current? What was drawing 3.4A? Was the 13.4V open circiut? Need more details on your measurements before anything can be said.

I second that.

I third that, what this post means? 😛

 

[stankonia3000]

Uh, like I said I don't know enough about electonics: I just plugged the AC adapter into the wall and then used the multimeter to measure - how else can I do it?. I can't reverse the polarity on the AC adapter because it is not one of those "mulit-plug" units; it just has one plug.

 

[dighn]

Originally posted by: dmcowen674

Originally posted by: stankonia3000
So I bought a scanline converter off the FS/FT forum, but it did not come with an AC-->DC Adapter. It takes 9V and draws 500mA of current, according to the user's manual.

So I go to the local, respectable electonics store and the lady shows me that all they have in the right "plug size" is 9V at 1A (1000mA) of current. She says the 1000mA is fine because my unit will only draw the necessary 500mA from it.

So I get home, promptly hook up the AC Adapter to the unit and plug it into the wall and....POP...I can tell that something fried immediately by the telltale smell and smoke wasping out from the inside of my scanline converter. So I bust out my Multimeter and see that the AC Adapter is actually outputting 13.4V and 3.4A of current.

I barely know anything about electonics, but does this sound right? Both the packaging and the label on the AC Adapter say 9V, 1A.

The unit should've been fine with the little extra voltage, most likely the polarity on the plug was backwards. There should be a fuse in your scanline that could be replaced, change the polarity on the adapter plug and you should be good to go.

yeah could be reversed polarity. although i doubt the device would still work after smoke came out... sounds like a poped capacitor and possibly other damage.

does the plug label what is the polarity? usually the inside is postive and outside is negative

 

[stankonia3000]

Well, the outside is + because that is what I put the postive mulitimeter lead on and got a postive Voltage reading...if I reverse; I get a negative reading.

 

[RossGr]

With no load a 9V adatpter could well read 13.4V, you need to have some kind'a load to get a meaningful voltage reading. Like wise for the current, if you simply shorted the contacts together with your ammeter, your reading may well simply be a function of your meter. This is not the recommened way of measuring current.

I go with the reverse polarity crowd, That is probably what happened.

If you've let the smoke out, there ain't no putt'n back in.

Sorry.