12v dc DVD player wired incorrectly ie. polarity reversed to a 12v dc battery pack

I had a working portable DVD player made by toshiba. That is until my wife yanked out the wires to its battery pack, And Just like a woman, she can't tell the difference between red wires and black wires and which goes to what. Im certain my 2 year old daughter wouldn't have had a problem wiring red to red and black to black. Yep leave it to the one I picked to spend the rest of my life with. oh dang!!
Anyways, I am curious to know if my DVD player is completely trashed or whether it can be fixed easily enough or not.
DVD player was wired backwards, and it died, There is no sign of life. What does wiring 12v backwards do to electronics and is this repairable?
Id greatly appreciate any advice on what I might be able to do, besides replacement of course, or giving it to the wife for her christmas present.. hehehe Thanks
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There may have been an intervening diode. If not, which is more likely, it's probably time to go shopping. After trying it with the wires properly placed.

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Michael B wrote:

After checking the diode whether it is burnt open.
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I kinda doubt if it is a diode! The purpose of a diode if fitted as part of the circuit is to prevent the 12 volt electricity going through backwards! Therefore a diode shouldn't (although it's not impossible) burn up. Some equipment omits items like that although a diode cost only a few cents, for economy. You could open it up just to see if their is something obviously burnt up (maybe an internal solidly soldered in fuse?) that could be cheap to fix. Could be the on/off switch if fitted has burnt up? Otherwise prob. not, (unfortunately) worth spending time or money on it. FWIW my neighbour who has bad luck with anything electrical managed to do the same thing with a flashing beacon for his highway tractor trailer. He blew the pi** out of the little printed circuit board inside by hooking it up backwards; and it don't flash no more! Not sure if it's fixable anyway. If you need 'at home' examples of how 'not to hook things up' here's a couple. One would not set up a casserole to cook a roast and then put it in the fridge to cook would you? One wouldn't put on a bra (or most any garments) inside out or backwards, would you? One wouldn't drive down the street or hang a picture on a wall backwards or upside down? Try to bang in a nail with its point outwards; the wrong way. Use salt instead of sugar? Read a book/newspaper backwards, etc.
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terry wrote:

Superheros wear their underwear on the outside.
[8~{} Uncle Monster
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terry wrote:

It can burn up if rever current is too mcuh. I am saying from experience!
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More likely burnt closed, or burnt short.
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Christopher A. Young
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Stormin Mormon (on backup computer) wrote:

The diode can burn up if reverse current is too much, I am saying this from experience. Believe me!
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Tony Hwang wrote:

Not much reverse current will flow through most diodes. There's no indication he exceeded any peak voltage ratings.
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CJT wrote:

Some diode has low PIV! Theory and real world situation is two different thing.
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On Fri, 31 Aug 2007 01:54:47 +0000, Tony Hwang wrote:

i just love how these arguments start.
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Tony Hwang wrote:

What's your point?
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Some DC devices put a diode (backwards) on the power input leads. So that if you wire the device backwards, it acts like a big short. Blows fuse, and protects the electronics. Some circuits call this a "protector diode".
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Stormin Mormon (on backup computer) wrote:

That would, of course, be _forward_ current.
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If a protector diode burns open, the device starts getting (reversed) current again. Not good.
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Many years ago, when I was more involved with CB radio. They used to put a diode inside the case of the CB, right next to where the power wires come in. If you wired it backwards, the diode would draw lots of current, and blow the power supply fuse. It would also typically short the diode.
The fix was to replace, and solder in a new diode. And the rest of the device would be fine. They called it a "protector diode".
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In the good old days, most (if not all) devices using polarized power supplies, had a blocking diode, to prevent failure in case of polarity reversal, regardless how it happend. Such a diode costs almost nothing in mfg. Its job was to prevent reverse current flow, which in most cases kills the electronics.
Today, as if by colusion, most devices are not protected. It's another way to get you to buy a new gadget. Once posted this question to an electronics group to see if it's now a common "design feature" to omit the 1 cent diode and hot flamed for being stupid.
Extreme case of penny pinching - do not buy from the same company. Your DVD is most likely thrashed.
RichK
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wrote in message

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You probably smoked a semiconductor or many. Odds are you can't repair it yourself. To idiot proof dc powered devices a neat trick is to install a bridge rectifier in line with the battery leads that way no matter how the battery is connected the circuitry recieves the correct polarity.
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On Thu, 30 Aug 2007 04:08:02 +0000, cmply wrote:

Shorted polarity protection diode and burnt trace if it wasn't fused. When properly fused, the diode will blow the fuse and not short. Probably fixable in the right hands.
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