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Akai AX-M400 home stereos

 
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PostPosted: Wed Oct 26, 2005 5:33 am    Post subject: Akai AX-M400 home stereos Reply with quote

Hi,

my 14 year old Akai AX-M400 stereos went quiet last week.
I opened the cover and it seems that two resistors are burned - R25 and R43.

Apparently this is some kind of typical fault for these stereos, because someone else have also exactly the same kind of problem and same resistors burned.
http://www.abcelectronique.com/forum/attachment.php?attachmentid=1391

http://www.abcelectronique.com/forum/attachment.php?attachmentid=1392

If I only spoke french, I probably would find the answer from this message board Razz
http://www.abcelectronique.com/forum/showthread.php?s=4c65be17fb0bbe4841be2141b42e1d4a&t=5966

Would anybody know what type of resistors are these two?

Br,

Kai
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PostPosted: Sat Nov 19, 2005 2:13 pm    Post subject: Reply with quote

Hi,

my amplifier developed exactly the same problem. Checking out the french web site I found one reference for R43 which 1.2 kOhm. However, the discussion circled around the zener diode D22 located next to R25.

A few years ago a repair shop exchanged TR8 and IC2 on the large heat sink and TR16 next to R43. At least the soldering of these components no longer has the factory look.

Good luck
christian
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Guest






PostPosted: Mon Mar 05, 2007 5:57 am    Post subject: Reply with quote

Hi,

The french web site was a good find...talks about the amplifier module and the pdf file for it STK4142II.pdf and associated circuits.
Basically suggesting that by studying the pdf data file should be able be to solve the circuit problem in the AX-M400.
Anyway the resistor values are 1K (R25) and 1.2K (R43) but use a higher wattage for R43 say .5w instead of the original .25W 1.2K resistor so as not burn out again.
As far the sound being quiet might be that the protection circuits for the amp have switched off the output on the STK4142 so might be to check there (see the pdf for details).
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PostPosted: Mon Mar 05, 2007 4:25 pm    Post subject: Reply with quote

Addendum to my last message - found 47uf Capacitor next to R25 had gone low capacitance (caused large ripple on the 30V supply rail) causing the protection circuit of sk4142 to trip - replacing this capacitor fixed AX-M400 after it had gone quiet.....

Hope this fixes yours

Regards

Rick.
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polish boy
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PostPosted: Sat Jan 07, 2017 10:46 pm    Post subject: Reply with quote

Thanks everyone for help!
I replace two resistors R25 i R43 with capacitor 47uF 35V and my amplifier is now working!!
Greatings from POLAND! ;>
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eieigoto



Joined: 06 Mar 2017
Posts: 5

PostPosted: Wed Apr 19, 2017 8:35 am    Post subject: Reply with quote

had gone quiet.....

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kakasmall



Joined: 23 Jun 2017
Posts: 6

PostPosted: Fri Jun 23, 2017 11:01 am    Post subject: Reply with quote

Nice site!thanks for post info about Akai AX-M400 with us.

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