B760: much much smoke...no problem found?

[gunnar walgraeve]

B760 much smoke...no problem found?

I was listening for about 15 minutes to several radio stations. Something I do on some day. Suddenly a huge grey smoke came out the B760. Compare it with toasted bread that was burning! As quick as possible I unplugged the B760. It smoke for something like 20 seconds. The smell of the smoke was not chemical, it was more natural like the smell of burning paper or wood.
After a few hours, I opened the B760 and could not find traces of the smoke (it only smells everywhere inside). Even the transformator appeared normally. And inside the four iron RF-boxes, everything was still "fresh".
I plugged again the B760 to the mains...and could enjoy again to listen to the radio !!! No sound degradation, no signal degradation...no other degradations found. I listened for more than 15 minutes...like nothing happened before...
Did someone have the same experience? Could it be situated in the transfo? Because it smelled more like burning paper: could it be that the transformator is still an old type with paper+oil as isolation?
One thing I didn't open was that "dish" (seems to be a filter) from below. But only two small coaxial wires are going in/out. I don't think that the problem came from there.
Off course, my B760 is dust free, so no dust that was burning.

Gunnar W. from Antwerpen - Belgium

[klingklang]

Maybe its just a simple, but well known Problem. In the 70 and 80th ITT build an Y Capacitor wich supresses Noise on the Power Cord. This part is truly dangerous, because sometimes it can burn. It would`nt be a suprise if you have the same Problem, cause all you discribed, even the smell, sounds like it would be an Y-Cap. Look for an Yellow cylindric Cap with three Pins. Remove him, cause you will not see the damage from above. Sometimes its on the Bottom Side. Maybe Revox has used other Manufaktors, but look at the Y-Cap.

[klingklang]

Forget all i told about the Y-Cap. Cause Revox Devices normally don`t use three Wire Plug-Cords.

So yust look for a simple 2-Pin Cap witch supress Power-Line Noise.

[gunnar walgraeve]

At the voltage selector (110V-220V-240V...) there is indeed a big capacity but made from plastic. I will check that one.
I must also tell that I changed many months ago the voltage selector to 240V because we are now running on 230V. But I don't think that could cause the problem.
Isn't it there for reducing the cos¥ (cosinus phi)in stead of reducing the noise?

Greetings
Gunnar W.

[klingklang]

I don`t think so. Because the Power Consumption of this Device is to less.

[gunnar walgraeve]

Indeed, the capacity which supress the power-line noise was broken at the bottom side (=>little explosion). Almost invisible because that capacity is situated in the darkest side of the TUNER.
Thanks to Mr. klingklang and also thanks to REVOX BELGIUM.

Gunnar W.