Quick question on fuses!

[christo]

I picked up a philips 42 inch plasma tv the other day, doesn't turn on just on and off. So I unscrewed the back and bam, there's 6 caps bulged and leaking.
Got my new caps today and replaced them, no go still turned on and off.

Checked the fuses on the board and here's the funny thing and my question.

I found a fuse fully blown in half, this guy put a 20a fuse in the t8ah/250v
and the t8ah/250v the t1a250 v spot.

Would this cause the capacitors to blow?

I guess my question is can you put these higher voltage fuses in lower fuses spots? I plan on getting the correct sizes for all of them, but the fuses that were in the board are still doing ok and reading 0.

[selldoor]

Re: Quick question on fuses!

It is unlikely using the wrong fuse would cause the caps to deteriorate it may be that the caps caused the original fuses to blow along with damage to other components.

[christo]

Re: Quick question on fuses!

It is unlikely using the wrong fuse would cause the caps to deteriorate it may be that the caps caused the original fuses to blow along with damage to other components.

If that's the case ill have to do a little bit more tinkering after i get the fuses replaced as the tv still doesn't want to turn on, just goes to on than off.

[MagicSmoke]

Re: Quick question on fuses!

The amp rating is what matters on a fuse not so much the voltage. 20amp fuse in a 8amp spot will cause all kinds of mayhem.

EDIT... unplug X & Y boards to see if PSU will stay on.

[christo]

Re: Quick question on fuses!

The amp rating is what matters on a fuse not so much the voltage. 20amp fuse in a 8amp spot will cause all kinds of mayhem.

EDIT... unplug X & Y boards to see if PSU will stay on.

I already did this still no go unfortunately, well i did one on at a time I'll report back with both unplugged.


EDIT..... I'm not going to try until i find the right fuse for 1a/250v don't wanna go over amps if that's what caused this from happening in the first place.

[drussell]

Re: Quick question on fuses!

I'm not going to try until i find the right fuse for 1a/250v don't wanna go over amps if that's what caused this from happening in the first place.

Get a few of them as it is quite likely that it is going to blow when you put a new, proper 1A fuse in...



Just a thought.

[christo]

Re: Quick question on fuses!

Get a few of them as it is quite likely that it is going to blow when you put a new, proper 1A fuse in...



Just a thought.

they come in packs of 3s down at electronics store so i should be good, to busy to go get them atm!

[christo]

Re: Quick question on fuses!

anyone know if a 4ah/250v would cause any harm ?

[drussell]

Re: Quick question on fuses!

anyone know if a 4ah/250v would cause any harm ?

If it is supposed to be a 1A fuse, using one that is 400% of the rating means you might as well use a direct short; it's not going to protect anything at all!

Use the correct fuse. They specified a 1A fuse for a reason, so it would blow at the right time and try to protect things.

Of course, since someone else already put a monster fuse in there you're probably looking at a whole mess of damage already to something that might well have been easily fixable. It's hard to tell, depends on what the problem is...

Check everything for obvious shorts and then try the correct fuse.

[christo]

Re: Quick question on fuses!

If it is supposed to be a 1A fuse, using one that is 400% of the rating means you might as well use a direct short; it's not going to protect anything at all!

Use the correct fuse. They specified a 1A fuse for a reason, so it would blow at the right time and try to protect things.

Of course, since someone else already put a monster fuse in there you're probably looking at a whole mess of damage already to something that might well have been easily fixable. It's hard to tell, depends on what the problem is...

Check everything for obvious shorts and then try the correct fuse.

okay thanks.

[selldoor]

Re: Quick question on fuses!

Google Dim Lamp tester - make one up? could save you fuses and components.

[drussell]

Re: Quick question on fuses!

Google Dim Lamp tester - make one up? could save you fuses and components.

A very good point!

A dim bulb tester is worth every penny of the $5 or so costs for the pieces at the hardware store or you may have stashed in a junk box when you're troubleshooting anything that may have shorts.

[christo]

Re: Quick question on fuses!

Google Dim Lamp tester - make one up? could save you fuses and components.

What would the tester be used on? I googled it but only found a video on how to make one.

Where would I start to try and find shorts?

Is there a possibility of a short because of this fuse situation?

What are the chances I get lucky and it's just the fuses causing issues.

btw I ran to the electronic store and they were all out of stock on the fuses I need :/

[drussell]

Re: Quick question on fuses!

What would the tester be used on? I googled it but only found a video on how to make one.

You plug the TV you're working on into it and if there are any shorts or excessive current draw for any reason the lightbulb lights up, absorbing most of the energy instead of blowing up components or fuses in the TV. What you are doing is running the TV THROUGH the lightbulb, using it as an indicator and load current limiter.

Where would I start to try and find shorts?

You'll need at least a basic digital multimeter. If you don't have one and, spending a few extra bucks on a half decent meter with a reasonable feature set pays off. You might be able to borrow a decent one if you know someone who has that type of equipment.

Is there a possibility of a short because of this fuse situation?

There is almost certainly some type of short or almost shorted defective component. That would be the most likely cause of a fuse blowing in the first place. The tragic part is someone went ahead and bypassed the fuse action by using a hugely oversized fuse in there so instead of just blowing again on the original fault, it may well have taken out a whole bunch of other stuff in the process.

What are the chances I get lucky and it's just the fuses causing issues.

btw I ran to the electronic store and they were all out of stock on the fuses I need :/

Virtually zero and
Drats! Murphy at it again....

[christo]

Re: Quick question on fuses!

You plug the TV you're working on into it and if there are any shorts or excessive current draw for any reason the lightbulb lights up, absorbing most of the energy instead of blowing up components or fuses in the TV. What you are doing is running the TV THROUGH the lightbulb, using it as an indicator and load current limiter.



You'll need at least a basic digital multimeter. If you don't have one and, spending a few extra bucks on a half decent meter with a reasonable feature set pays off. You might be able to borrow a decent one if you know someone who has that type of equipment.



There is almost certainly some type of short or almost shorted defective component. That would be the most likely cause of a fuse blowing in the first place. The tragic part is someone went ahead and bypassed the fuse action by using a hugely oversized fuse in there so instead of just blowing again on the original fault, it may well have taken out a whole bunch of other stuff in the process.



Virtually zero and
Drats! Murphy at it again....

UPDATE

,threw the new fuse in, and I am now getting a 6 red blinking light signal meaning a 5v fault.

I found a thread with the same issue and am hoping it is the 7u25 mosfet.
https://www.badcaps.net/forum/showthread.php?t=34995

Now hopefully i can locate this sucker and get some results, any help on locating it would be appreciated.

[selldoor]

Re: Quick question on fuses!

It looks like this
http://www.digikey.ca/product-detail...3TR-ND/2622319

[christo]

Re: Quick question on fuses!

It looks like this
http://www.digikey.ca/product-detail...3TR-ND/2622319

Is this the exact model? I'm just wondering as I'm pretty sure this is the problem and will need to order it.

It's underneath the board and has some black goo on the pins, look's in rough shape ha.

[christo]

Re: Quick question on fuses!

Pulled it mosfet off which I assume is the right one since it had black goo on the prongs, don't think there is anyway of me repairing it now because a bit of the board came with the mosfet.

[selldoor]

Re: Quick question on fuses!

You are too impulsive - why dont you ask before you do something?
You should have tested it BEFORE you tried to remove it.
Depending on the result of the test then you might have been asked to remove it.
YOU should have compared the part number of the component on your board
before destroying it.

I mentioned before about pictures - if you post a good clear picture of the damage
zone we may be able to suggest how to repair it - if repairable