Want to replace resistors myself, but need an advice

Are you sure it's those resistors that burned? It's not uncommon for them to discolour if used at their limit.

Although the right one discoloured a lot .

What's on top of the IC? Is that glue, grease or damage?

The black component just below the yellow transfo, is that a capacitor? If yes, it may be dead.

Hi mate

Thanks for your prompt response.

I attached additional pictures.

On the top of IC - it is the glue.

I did make the picture of capacitor.

Thanks,

Vlad

Attachments:

I think the resistors had a hard time but they did not burn. A burned power resistor is powder.

The capacitor looks bad. Can you please take a photo of the markings. 5 photos from the top is enough

Hi Vlad,

I agree with Jan that the black capacitor near the transformer looks like it has over heated and is probably damaged. If you have a meter it would not hurt to measure the resistance of the heat damaged resistors before you try to remove them. I have seen where a color band will change from a color to black when heated to an extreme. Based on the physical size of the resistors relative to the other components my guess would be that they are 1/2 Watt. With the damage to the capacitor and the resistors be aware that they may be symptoms of a failure and not the actual failure itself. There is a reddish brown cylinder on the board near the white relay. I would like to know what the markings on it are. I was trying to imagine what would cause resistors and a capacitor to over heat and what comes to mind is the failure of a rectifier. This would allow AC to be applied to the DC side of the circuit and short out the capacitor which in turn would cause a higher current and over heat the resistors. Of course this is speculation based on insufficient information so it is only one idea. In any case I would look at all the components whether they have visible damage or not before reapplying power.

John

A couple more things. When you add pictures use this icon from the tool bar and your pictures will show in the text. Also if you can read the markings on the IC it might tell us more about how the circuit is configured and works.

John

The power rating can usually be deduced from the physical size.

These look to be about 1W. but I'm not sure from the picture exactly how big they are.

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They don't look burned enough to be smelling burnt - you can take a close sniff to see if they still smell burnt.

They actually look closer to 3W ones... I have some 5W ones that seem bulkier than it, but if you go on the safe side maybe just get 5W ones, more pricy but it's better than using a 1/4W.

They also don't look burnt, as you said..

The transformer's plastic looks like it's been a bit melted at one point. Maybe.

hugohu  wrote:

 

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The transformer's plastic looks like it's been a bit melted at one point. Maybe.

A melted transformer looks bad and smells bad. A burned transformer smells burned. This one looks OK. The shrink hasn't discoloured.

There may be a fuse hidden inside the transfo primary windings. A practice some manufacturers do to avoid meltdown of a transfo. That's easily detected with a continuity test.

In that case, don't fix it. The transfo has heated up beyond reasonable temperature and should not be fixed. That's why the fuse isn't replaceable. You can fix it but you should not.

Hmm, my bad.

Sounds like a voice of experience.