Rotel RA960BX Heat Damage

[TellMeWhy]

I recently purchased a Rotel RA960BX integrated from the German auction site and it seems to run hot (almost too hot to touch on a 4 ohm load. I've read other reports of this being the norm, but opened it up anyway to have a look.

As you can see, there's obvious heat damage to the plastic casing of the power supply caps and the resistors next to the heat sink. I haven't checked the bias and DC offset yet but I guess that would be a start.

My question is if this cosmetic heat damage may have damaged the components themselves (other than shortening the life of the caps which I realise)? The amp seems to work great, sound is perfect, power is ample for 60w.

Thoughts?

 

[mbz]

My question is if this cosmetic heat damage may have damaged the components themselves

I don't have a good answer for you. I tend to think of these components as behaving like steal, they have an elastic region that when pushed
they are happy to bounce back. Beyond that there is some residual damage/degrees of failure.

Looking at the main caps AND resistors I would suggest checking that everything was 100% in the power supply area. Rectifier, probably replace any
transistors and better filter caps(uf/V/ripple...). If all in order and it still sounds great then i'd rest easy.

 

[SoCal Sam]

Change resistors, not expensive. Change caps for 105d rated. I might be tempted to turn the bias volage down a little to limit heat.

 

[century tek]

Also try not to use 4Ω speakers.