Name that resistor! From a Rosewill DR-8500BTX

[udfxrookie]

As much as people state these things are crap, which they may be, this one has lasted me about three years now.
However today I was working on the PC and instantly it just shut down. After troubleshooting it was determined the power supply.

Upon inspecting the inside there are no burnt smells,no bulging capacitors and the inline fuse isn't blown... however this resistor looked burnt out and the black shielding was burnt away.

Here's the culprit:


Can anyone tell me the size I need to get to replace this?

Called Rosewill and they stated that another company makes these and they simply slap their label on it, but have NO clue how they work or how to troubleshoot... that's always what I love to hear when purchasing from a company.

[budm]

Re: Name that resistor! From a Rosewill DR-8500BTX

All I say is that it is MOX Flame proof type resistor, I cannot see the color bands clearly.
You have to measure the body size to estimate the Wattage base on the dimension spec.
What resistance are you getting and how it is connected in the circuit, that will help determine the function of this resistor.

[keeney123]

Re: Name that resistor! From a Rosewill DR-8500BTX

I think you would be safe with a 5 watt. It might be smaller? If you have enough room I think a 5 watt would work. Can you tell what the colors are left to right? Have you measured with a DVM?

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

Size wise measures 15/16 of an inch....just shy of 1"

The bands look: Gold, grey, black, yellow...just not 100%

Here is a picture from where it came from (notice the black circle bottom right)


and here's the ohms I get from it:

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

Only visible markings on the black casing are:
E2273 (looks like another 3 and then the rest is cracked off)

[budm]

Re: Name that resistor! From a Rosewill DR-8500BTX

The black casing is just the black shrink tubing.
Can we see the straight shot picture of the bottom side of the board, the resistor may be OK since it did not go open circuit but the color bands may have changed due to heat.
Yellow/Grey/Black would be 49 Ohms which is odd value instead of typical 47 Ohms.
May be it is Yellow/Violet/Black = 47 Ohms?
It is in the Primary side of the circuit.

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

I understand the shrink wrapping but wasn't sure if the markings indicated the resistor under it.
All the other caps and resistors look great, this is the only one that had the shrink wrapping cooked to the point it was falling off AND the resistor coating with the color bands are also flaking off.

Here's the bottom of the board: (black circle top right)


Another shot: (black circle bottom left)

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

If these colors are close Gold, grey, black, yellow (or yellow/grey/black/gold)

4-8-1-5 = 48K Ohms +/- 5%
correct?
Would that be normal on a PSU?
(https://itll.colorado.edu/index.php/...esistor_chart/)

[keeney123]

Re: Name that resistor! From a Rosewill DR-8500BTX

Only visible markings on the black casing are:
E2273 (looks like another 3 and then the rest is cracked off)

What was the black shield pressed up against? I am thinking the black shielding was protecting a component from the heat of the resistor.

[budm]

Re: Name that resistor! From a Rosewill DR-8500BTX

It looks like that resistor has one end connected to the brown ceramic disc capacitor to form RC Snubber circuit for that Diode?
Th brown ceramic cap tested OK and does not show any leakage resistance? The Diode tested OK?

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

The brown ceramic cap shows nothing when testing resistance (.0L), the diode tested ok.

@keeney, the resistor was pushed against the blue cap circled in the first pic, shows a bit of darkness from the resistors casing touching it but looks fine.

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

Little brown cap is 222k 1kv (shows an r next to the 1kv but no clue what that is)

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

So I need a 48K Ohms +/- 5% resistor and a 222k 1kv capacitor? =)

[Th3_uN1Qu3]

Re: Name that resistor! From a Rosewill DR-8500BTX

That circuit is not your problem, the primary switchers will work without it, just with lower efficiency and higher risk of blown parts at power surges. Most likely the primary switching transistors have failed in a way that did not blow the fuse (open). Do you have 5vsb (standby voltage) at the purple wire in the ATX connector? Measure between that and any of the black wires.

[udfxrookie]

Re: Name that resistor! From a Rosewill DR-8500BTX

There is a purple wire, when hooked up through the multimeter to one of the black it starts reading and bounces all over the place.
What should it be reading?

[keeney123]

Re: Name that resistor! From a Rosewill DR-8500BTX

If these colors are close Gold, grey, black, yellow (or yellow/grey/black/gold)

4-8-1-5 = 48K Ohms +/- 5%
correct?
Would that be normal on a PSU?
(https://itll.colorado.edu/index.php/electronics_center/resistor_chart
/)

The colored one separated from the other three colors is your percentage of tolerance. If it is gold then it would be +/-5% of the of the other colors value. If it is brown it would be +/-1%. The first two are the value and the third is the multiplier. The first color is not gold perhaps as BudM suggested it is yellow. The second value is not gray because that would not be a standard size. I would agree with BudM's violet as the color could have faded. The third one is black which is a zero multiplier. Which would make the value 47 Ohms. Your meter is measuring 49.3 Ohms.The meter has a tolerance that will be in your manual. Then the last thing we need to figure out is the tolerance of the resistor. BudM says it is a part of a snubber circuit I would think the tolerance would be 5%. So if you take a 47 Ohm resistor and take 10% that is 4.7 Ohms divided by 2 will give 5%. So that would be 2.35 Ohm of tolerance. That would then make the resistor 47 ohms + or - 2.35 Ohms To me the 49.2 Ohm resistor is good unless something happens to it under power, which I would not suspect right now.

[keeney123]

Re: Name that resistor! From a Rosewill DR-8500BTX

Seems Th3_uN1Qu3 is familiar with this circuit so I would follow his instructions.