Akai Preamp PS-200C wird zu heiß

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beginner16
Neuling

#1 erstellt: 21. Jul 2007, 08:34

Hallo,
schon lange erfreue ich mich an der kombination aus AKAI PS-200C preamp PS-120M endstufe und PS-200T tuner.
jetzt ist mir - hoffentlich noch rechtzeitig - aufgefallen, daß der vorverstärker enorm heiß wird. nach entfernen der oberen verkleidung konnte ich den Trafo mit der aufschrift PS-200C-T40 als übeltäter ausmachen. dieses schwarze teil sitzt direkt hinter dem kältgerätestecker und ich nehme an, daß es ein trafo ist. wenn ich die handfläche drauf lege ist es so heiß, daß man eier braten könnte. ich hbe auch noch die untere verkleidung abgeschraubt und verfolgt, ob hitzespuren auf den platinen zu erkennen sind - fehlanzeige.
trotzdem funktioniert das gerät "noch" einwandfrei, ich weiß aber nicht, wie lange. deswegen traue ich mich nicht mehr, das gerät zu gebrauchen.
ist das am ende normal oder was meinen die fachleute dazu?
bitte geizt nicht mit eurer meinung bzw. tips danke tom

[Beitrag von beginner16 am 18. Jul 2007, 20:25 bearbeitet]

http://www.chip-foto...-AKAI-PS-200C/112707

tri-comp
Stammgast

#2 erstellt: 21. Jul 2007, 09:48

Hi,

YES, you are right, it's an ordinary transformer. Not a fancy modern switching power-supply (...unfortunately, because then I would have some suggestions as to what could be done)

If the transformer is getting hot in this environment, something seems to be constructed in-efficiently. The heat that is generated indicates some considerable amount of power is taken from the transformer. But where could it go?? There are no high-power circuits in a pre-amplifier that consumes a lot of energy. Still, the defective rectifier/bridge rectifier in the power-supply circuit could be the cause, but then it should get HOT ...or SOMETHING should get hot besides the transformer. Throwing away a lot of power leaves heated components usually. Check by touching all components if they are HOT out of the usual :

daß man eier braten könnte

Also, you could check if the amplifier is set to 220V AC and if there is a possibility to switch it to 240V AC. Do it, if it's possible. It will also reduce heating but have no influence on the amplifier performance.

Kind regards,

/tri-comp

beginner16
Neuling

#3 erstellt: 21. Jul 2007, 10:32

tanks for superfast answer.
i switched on the amp 15 min ago, it not getting hot fast but slowly.
but what is gettin really hot are the 4 cooling cubes directly behind the trafo. u can see it on the foto.
hope u understand my horrible explainings. thanks again tom

tri-comp
Stammgast

#4 erstellt: 21. Jul 2007, 10:51

Your answer is easy to understand, but you can write in German if you like. I read it well enough, just writing is a problem

The 4 cubes are just heat-sinks with a transistor mounted on each. They should normally get somewhat hot, but not really to the extend, that you could not touch them for seleral seconds. The transistors on these heat-sinks usually develop bad connections where they are soldered onto the printed circuit board. If they are as hot as you describe, I would check now and absolutely re-solder each one. This isn't to cure your heat-problem, just to prevent future faults. The problem is, they can be hard to get at. If you can remove the bottom-plate it's easy to do the resoldering. If not, the entire board may have to be removed for the soldering.

I'm afraid you'll have to live with the heating of the power-transformer if it can't be switched to 240V AC. Not all electronic circuits are constructed equally well.

Kind regards,

/tri-comp