resistor wattage help

[multimeter]

hi guys,trying to find the wattage of a resisor,this one is a 0.22 ohm 10% (color bands ,red,red,silver,silver),no schematic so unsure of wattage size,power board is bn44-00158a ,resistor location on board is,rm801,from samsung 23"lcd tv,resistor is coming off the positive from main filter cap,(82uf 450v),cheers

[amazinguk]

Re: resistor wattage help

You can use a wattmeter and measure the wattage as voltage and current is applied to the resistor at a given resistance.

resistors come in different wattage values( 1/8w, 1/4w, 1/2w, 1w etc) You should be able to find the schematic here:


http://elektrotanya.com
write in your model number and it will allow you to downlload. select
--> (per service)

[budm]

Re: resistor wattage help

That is more likely to be the resistor for the Source pin of the MOSFET, typicaly will be 1Watt (you can use 2 watts if you have the room) Flame proof metal oxide resistor. Verify if it is connected to the Source pin of the MOSFET. if itis connected to the + leg of the 82uf/450Vdc cap, then it may be used as fusible resistor for the B+ LINE, then it will be 1/2w or so.
Any pictures of the board and the resistor?

[tom66]

Re: resistor wattage help

You can't measure the watt rating of a resistor; because that's a power dissipation rating, not a circuit characteristic.

You can dissipate 1W in a 1/4W resistor for several minutes without failure of the component; 10W can be done for a ~1-2 seconds and >10W pulse power might be possible for milliseconds.

The best estimate of power dissipation is the size of the component: approximately how big is it?

In the worst case buy several if you're not sure, as resistors cost pennies each!

Budm's advice is good - use this to estimate the power rating. I've also seen 3W source resistors too. Usually if that resistor is burned, something else is too.

[multimeter]

Re: resistor wattage help

my camera is crap,but found the image on google,resistor is just to the right of main filter cap,this supply is pain in the ass,just wont fire and give the main board its 12v,changed pwm,also the usualy problematic f9222l ,output caps,this resistor is showing 0.00 ohms or short, when it should be 0.22 ohm,so not sure !,only thing havent checked yet is the switching buck regulator,but there aint any voltage getting to it anyway,all mosfets,diodes check good,only voltage outputting is the 5v stb,discconecting the main board or others makes no difference,the supply will hiss then click,hiss then click etc,this sound is coming from the pwm (viper 12a),its getting a stable 22v,other checkpoints when measuring voltage,on the diode side of optocouplers ,the voltage is up in down tallying with the noise from the pwm,bloody stumped me this one!,no dry joints either,all high voltage caps checked,and insulation tested up to 1000v,it cant be the main board beacause it should need more than the 5 odd volts that its getting to work properly!,no 12v

[sofTest]

Re: resistor wattage help

If you give us the TV-model, someone might find you the schematics or the service manual.

[Radio Fox]

Re: resistor wattage help

...this resistor is showing 0.00 ohms or short, when it should be 0.22 ohm...

Is that when measured whlle still in-circuit, or did you take it out to measure it?

[budm]

Re: resistor wattage help

What resistance do you read on your meter when you short the test lead together? I doubt that it will show 0.00 Ohm. That resistor looks like for the Source of the MOSFET on the top right of he pictures that drive the large transformer on the mid-rIght of the picture. The resistor is OK, I would worry if it is open.

[multimeter]

Re: resistor wattage help

Is that when measured whlle still in-circuit, or did you take it out to measure it?

one leg out of circuit

[multimeter]

Re: resistor wattage help

What resistance do you read on your meter when you short the test lead together? I doubt that it will show 0.00 Ohm. That resistor looks like for the Source of the MOSFET on the top right of he pictures that drive the large transformer on the mid-rIght of the picture. The resistor is OK, I would worry if it is open.

test leads shorted =0.00 ohm

[budm]

Re: resistor wattage help

Test leads show 0 Ohms, your meter has the ZERO adjustment pot to compensate for the test leads resistance, MY Fluke 87 and 187 show about 0.5 Ohms for the test leads reistance, I have not seen DMM with ZERO adjustement capability, must be some meter you have there. By the way, what is the model number of this TV you are working on so I can try to look up the diagram for it.
See here to find out if it has the same bad cap: http://www.electro-tech-online.com/r...psu-fault.html

[multimeter]

Re: resistor wattage help

Test leads show 0 Ohms, your meter has the ZERO adjustment pot to compensate for the test leads resistance, MY Fluke 87 and 187 show about 0.5 Ohms for the test leads reistance, I have not seen DMM with ZERO adjustement capability, must be some meter you have there. By the way, what is the model number of this TV you are working on so I can try to look up the diagram for it.
See here to find out if it has the same bad cap: http://www.electro-tech-online.com/r...psu-fault.html

il give you my readings ,leads shorted-
200ohm=00.8
2kohm=.001
20kohm=0.00
200kohm=00.0
2mohm=.000
20mohm=0.00
200mohm=01.0
the tvs model number is: samsung LE23R86WD
psu BN44-00158A
something i have noticed,is when the main board is connected the ps-on voltage jumps from 5.3v down to about 1.6v and this happens every 2 seconds,5.3v then low,5.3v then low etc, wether the tv is in standby or not makes no difference,also the touch sensor buttons on tv have no response,the remote works,when pressing the power on button,front tv led light goes off(think that is correct for samsungs).max voltage from psu is a measly .62v on the 12v,24v rails,ive tried powering the supply without main board ,with the ps-on jumperd,no voltages come up ,BUT the standby 5.3v is stable at 5.3v,main board attached ,up and down like a bluebottle with the shits!

[budm]

Re: resistor wattage help

Now I see, when you try to measure low resistance value, you hsould use the lowest scale to get better resolution, in this case, you should use 200 Ohm scale.
The main board is cycling on and off, I am sure that will not be the only signal that is doing that either. The 5VSTBY is always steady?
So far I cannot locate free download of the diagram for this power supply board yet.

[multimeter]

Re: resistor wattage help

Now I see, when you try to measure low resistance value, you hsould use the lowest scale to get better resolution, in this case, you should use 200 Ohm scale.
The main board is cycling on and off, I am sure that will not be the only signal that is doing that either. The 5VSTBY is always steady?
So far I cannot locate free download of the diagram for this power supply board yet.

the 5v stb is steady when the main board is detached,cycling when main board is connected,nearest ldo on the main connector into the main board is reading 5.3v,thats the highest voltage i can find on the mb when probing around,the main board must have to recieve a 12v signal for anything to work surely!,this is where im getting confusion as to if its the psu or mb at fault,normally i can get them to fire up on there own with no boards connected,apart from a dummy load,im really edging toward the main board,maybee its sharing its stb voltage to also tell the rest of the psu to start !??,but that would be a strange assumption beacause it must need more voltage than 5v!

[budm]

Re: resistor wattage help

The 12v and the 24v will not be on until the main board puts out steady PS_ON to keep the 12/24v on. The 5Vstby should be steady when the main board is connected, so what you can do is to load the 5Vstby output with 10 Ohm 5w resistor (this will cause the 5Vstby to suppy 1/2A of current through the resistor and it should be able to handle that OK (Toal power will be about 2.5Watts). There should be label some where on the board that tell you the output voltages and current of the outputs. I cannot see that well in the picture.

[Scenic]

Re: resistor wattage help

So far I cannot locate free download of the diagram for this power supply board yet.

There doesn't seem to be one. I've got most of the Samsung I/P Board PDFs which are floating around the net, but the 00158A isn't in there.
The list jumps straight from the 00147A to the 00191A

http://www.4shared.com/account/dir/e...#dir=138399196

[multimeter]

Re: resistor wattage help

output voltages and the amperage as follows:
24.5v 3.0a
5.3v 4.0a
12v 0.3a
9.2v 0.5a
5.2vsb 0.3a

[budm]

Re: resistor wattage help

@Scenic, I download all the BN-XXXXX that you had posted in the forum which was great, thanks to you, I am sure some one out there has the diagram of this board.
By the way, the link you provided, 4shared, it asked to pay to join/download, they are not free download?

@multimeter, so the 5Vstby can supply 0.3A, so it should be able to handle the 10 Ohms load with no problem.
I am not sure about the 5.3A 4A and the 9.2V 0.5A are switched on the PS_ON signal or it is also always on just like the 5Vstby supply.

[multimeter]

Re: resistor wattage help

@Scenic, I download all the BN-XXXXX that you had posted in the forum which was great, thanks to you, I am sure some one out there has the diagram of this board.

@multimeter, so the 5Vstby can supply 0.3A, so it should be able to handle the 10 Ohms load with no problem.
I am not sure about the 5.3A 4A and the 9.2V 0.5A are switched on the PS_ON signal or it is also always on just like the 5Vstby supply.

no other voltage apart from 5.2v is on,wonder why no schematic available for this supply ?,all others but not this one!i think ive tested nearly every part on this psu ! apart from the power ic,which i dont know how to test,but if that was knackerd then it proberly have taken out the fuses,some transistors etc

[budm]

Re: resistor wattage help

This board looks familiar, please check those resistors, make sure they are not open. If I am correct, they should be 68 Ohms resistors.