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It could be a transistor, or it could be almost anything else.
You need to have some rational method of figuring out likely suspects.
Start with an examination of the board. Many components will show signs of failure (but beware of components which are just being operated close to their limits and may be scorching the board -- especially true of wirewound resistors).
If there are no visible signs, there may still be the smell of the magic smoke that was released -- there may also be marks on the case where the smoke went. This may lead you to a particular area.
If a fuse blows, then the fault is obviously one that causes high current to flow, so start checking components that are capable (if shorted) of causing large currents (e.g. output stage, filter capacitors, some diodes).
Next step is to disconnect the load from the PSU (careful of this as the PSU may require a minimum load) and check if the fault is in the PSU.
Then there's lots more you can do before you start replacing (or suspecting) components at random.
So the first question therefore is, *why* do you think it's this transistor?
You need to have some rational method of figuring out likely suspects.
Start with an examination of the board. Many components will show signs of failure (but beware of components which are just being operated close to their limits and may be scorching the board -- especially true of wirewound resistors).
If there are no visible signs, there may still be the smell of the magic smoke that was released -- there may also be marks on the case where the smoke went. This may lead you to a particular area.
If a fuse blows, then the fault is obviously one that causes high current to flow, so start checking components that are capable (if shorted) of causing large currents (e.g. output stage, filter capacitors, some diodes).
Next step is to disconnect the load from the PSU (careful of this as the PSU may require a minimum load) and check if the fault is in the PSU.
Then there's lots more you can do before you start replacing (or suspecting) components at random.
So the first question therefore is, *why* do you think it's this transistor?
i have found a component that looks like it might have blown up or something but dont know what it is heres the link to the pic its circled.
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=dvdcircuit.jpg&newest=1
if cant see that one here another
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=DSCF0419.jpg&newest=1
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=dvdcircuit.jpg&newest=1
if cant see that one here another
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=DSCF0419.jpg&newest=1
That's a coil, or an inductor if you will, lying on its side. The silkscreen print should say L-something. It doesn't look burnt but there's some kind of deposit around it.
Is the any smell of the deposit? Does it clean easily? Has C614 ever been there btw.?
Apart from that I can't contribute with anything more than steve's already done. You mention fuses & transistors but we can't see them from here, so...
Is the any smell of the deposit? Does it clean easily? Has C614 ever been there btw.?
Apart from that I can't contribute with anything more than steve's already done. You mention fuses & transistors but we can't see them from here, so...
How did it become not working? Knowing this might help in trouble-shooting it.
For instance, portable devices often end up being used in places they probably shouldn't be (like around food and drink). Did something get spilled in it?
Also, portable devices get moved around and sometimes dropped. In this case you would be looking for a hair-line crack on the board.
You said the power-supply is internal, but since these devices often get separated from it's AC adapter, I often see them getting blown up by people using the wrong AC adapter on them (just because the plug fits)
As far as the power supply goes ... how much voltage is it putting out?
You might try disconnecting the optical drive and see if the PS will power the main board without blowing the fuse.
For instance, portable devices often end up being used in places they probably shouldn't be (like around food and drink). Did something get spilled in it?
Also, portable devices get moved around and sometimes dropped. In this case you would be looking for a hair-line crack on the board.
You said the power-supply is internal, but since these devices often get separated from it's AC adapter, I often see them getting blown up by people using the wrong AC adapter on them (just because the plug fits)
As far as the power supply goes ... how much voltage is it putting out?
You might try disconnecting the optical drive and see if the PS will power the main board without blowing the fuse.
The yellow stuff looks like glue to me (perhaps to damp the inductor from vibrating). I can't see leakage from anything flowing that way. If it seems like glue and you can't clean it off the side of the capacitor, then it probably is.
I would suspect that you have removed C614, but if not, it looks like it was once there. I compared it with another set of "unused" holes and they looked very different.
Leakage from capacitors generally exhibits one of three forms:
1) explosive -- it gets splattered everywhere. You're not left wondering.
2) swelling with or without small amounts of localised leakage (day a spot of brown on the top or bottom of the capacitor.
3) leakage. In this case it goes where gravity takes it. I've seen brown streaks running from a capacitor right down a board (that was mounted vertically) and off the edge, and others only a couple of mm long.
Where a board is horizontal (and not upside-down) you will expect leakage to form a pool around or on one side of a capacitor. In this case it is conceivable that it could have gone up the side of the capacitor a little, but not up and over the inductor without spreading more widely over the board.
The colour is generally darker than that too.
Tesla's question regarding the history of the device and the fault is important (and I thought I'd asked, but it may have been in another thread about something else)
I would suspect that you have removed C614, but if not, it looks like it was once there. I compared it with another set of "unused" holes and they looked very different.
Leakage from capacitors generally exhibits one of three forms:
1) explosive -- it gets splattered everywhere. You're not left wondering.
2) swelling with or without small amounts of localised leakage (day a spot of brown on the top or bottom of the capacitor.
3) leakage. In this case it goes where gravity takes it. I've seen brown streaks running from a capacitor right down a board (that was mounted vertically) and off the edge, and others only a couple of mm long.
Where a board is horizontal (and not upside-down) you will expect leakage to form a pool around or on one side of a capacitor. In this case it is conceivable that it could have gone up the side of the capacitor a little, but not up and over the inductor without spreading more widely over the board.
The colour is generally darker than that too.
Tesla's question regarding the history of the device and the fault is important (and I thought I'd asked, but it may have been in another thread about something else)
no this device was only mounted to the back of a cars headrest, we had it for about a year and a half then one day we tryed pluging it up but it wouldnt do anything. thats when i desided to take it apart to see what i could do sence this is what im going to school for. if someone did plug the wrong adapter into the dvd player what does it hurt i dont think anyone ever did?
the power supply has 120v going to the main board, I'll try your idea tomorrow about seeing if the ps will power just the main board without blowing the fuse.
the power supply has 120v going to the main board, I'll try your idea tomorrow about seeing if the ps will power just the main board without blowing the fuse.
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A different adapter could be a different voltage or polarity.
EDIT: It has 120v but you use it in the car?
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Connector voltage polarity ... as in the positive and negative are reversed ... yes, that would be bad. Luckily, (if it's a common round plug) the outside is usually negative and the inside is positive.
No, I'm pretty sure a power adapter (even car ones) can be made to output different voltages. It depends on the circuitry inside the adapter. Often, the adapter's output voltage is written on it ... or where it plugs into the DVD player case.
If you really want to fix this device ... the make/model and some better pictures would go a long way.
From your written description so far ... I find it unlikely that 120 volts are involved. Do you think maybe the 120v is describing the rating on the fuse?
Speaking of the fuse ... are you sure you are replacing it with a fuse of the exact same rating (amps/voltage/Fast-Slow) as the one you originally pulled out?
its a Audiovox PVS69701, i have taken a couple more pics well post the links hope i can find out what wrong?
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff179.jpg
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff180.jpg
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff169.jpg
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff179.jpg
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff180.jpg
http://s743.photobucket.com/albums/xx72/red_sx4/?action=view¤t=jeff169.jpg
I see where it says 125v ... yes, that appears to be part of the fuse rating ... 3A @ 125v ... never install anything bigger. What kind of fuses have you been using as replacements?
On the original power adapter that plugs into the car ... what does the label say on it about the output voltage? When you double check it with a meter, what do you get?
On the original power adapter that plugs into the car ... what does the label say on it about the output voltage? When you double check it with a meter, what do you get?
i had to use a different kind of fuse because the original fuse looked like a resistor and couldnt find one to replace it with so now im using a circle fuse at 3a@125V. the original adapter doesnt have a anything on it but i know it came with the dvd player. on the side of the dvd players case it says car plug 12V, DC in 9V.
can u test a diode in the circuit?
when i tested the adapter i got 12.32V DC
can u test a diode in the circuit?
when i tested the adapter i got 12.32V DC
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To get an accurate check on a diode, you usually have to unsolder at least one leg (so you aren't reading other parts of the circuit).
That's what I thought ... the player runs on 9v DC (not 12v DC). It sounds like the adapter might not be stepping down the voltage properly. See what the cig-lighter socket voltage is. On my Honda, it's 11.8v . Compare the adapter's input voltage to the output voltage. I would think there should be a 25% decrease (if the adapter is working properly).
