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Marantz => Techniek => Topic gestart door: imac op december 16, 2009, 20:18:40

Titel: Marantz SR-14 idling current problem
Bericht door: imac op december 16, 2009, 20:18:40
Have problem with setting the idling current on my SR14, then I set it to 4mV (30 m warm up) and wait for say 10 m the it will be from 2-6mV.. If I blow gently on the circuit board then it will drop from 4 to 1mv in seconds!

The same if I put the lid on at wait 10 m then it will rise from 4 to 12mV. Should it be so sensitive or is it some problem with the amplifier? It's the same on all five channels..

Have tried out some other forum without any luck, hope that someone here can help me, even though that I'm write in English and not Dutch, I'm from Sweden :-)
Titel: Re: Marantz SR-14 idling current problem
Bericht door: Marvin op december 16, 2009, 20:33:39
welcome, i certainly can't help you...
but if you won't get any further at this forum, you can try the www.hififorum.nl .
there are a bunch of sparky's over there....

this would be a fitting topic   link (http://www.hififorum.nl/index.php?PHPSESSID=dbc858d5a59e8f2fa2bbffc13264d62e&board=5.0)

good luck with you're stunning machine.....!!

Marvin.
Titel: Re: Marantz SR-14 idling current problem
Bericht door: HAL9000 op december 17, 2009, 09:25:16
No HiFIforum will not have the answer,

I would look for diodes, these are the only ones that are susceptible for T variation.
Also transistors that are dissipating a lot of energy.

But do you notice this in your sound?? or in the working of the amplifier?
Like abnormal swinging of the bass units in you speakers.??

Titel: Re: Marantz SR-14 idling current problem
Bericht door: imac op december 17, 2009, 10:13:21
I have change the power transistors and some more resistors on the center channel and after that I did the check of the idling current..

Titel: Re: Marantz SR-14 idling current problem
Bericht door: HAL9000 op december 17, 2009, 12:21:50
Power transistors as in output once?? on the big heat sink??
these will not be broken, it should be your bias circuit.

I'm still guessing a Diode.
Titel: Re: Marantz SR-14 idling current problem
Bericht door: imac op december 17, 2009, 13:19:15
That's right, outputs transistors, they was smoked then I got it. It was after that I have change them that I discover this.
Titel: Re: Marantz SR-14 idling current problem
Bericht door: sattie op december 17, 2009, 17:46:06
Have you resolderd the board ?
Titel: Re: Marantz SR-14 idling current problem
Bericht door: HAL9000 op december 18, 2009, 12:01:22
Citaat van: imac op december 17, 2009, 13:19:15
That's right, outputs transistors, they was smoked then I got it. It was after that I have change them that I discover this.

You need to replace one transistor on your board.  it is for bias  :wink:

re-soldering a board will have No effect on this problem.