If no sound can be easily solved by a reset button, there is no point in calling a tech for help.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/xwink.gif.pagespeed.ic.cldandycH0.png)
There are at least 10 reasons for no sound.
![WTF? :wtf:](https://www.eevblog.com/forum/Smileys/default/wtf2.gif.pagespeed.ce.pxLiY5pjs4.gif)
In spite of various brands of av amps, working
principles of yamaha, pioneer, onkyo, sherwood and anthem are same
![Cool 8)](https://www.eevblog.com/forum/Smileys/default/xcool.gif.pagespeed.ic.cOxV6sPNRd.png)
except denon and marantz
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
due to one more chip involved in digital decoding board.
How to troubleshoot? see pm. Waveforms and their names see photos and pm.
![Popcorn :popcorn:](https://www.eevblog.com/forum/Smileys/default/EatingPopcorn.jpg.pagespeed.ce.yJ6TmC5fSa.jpg)
You must have an oscilloscope at least 40MHz. No oscilloscope no talk.
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
Single channel is more than adequate. Follow the steps and read them carefully.
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/xcheesy.gif.pagespeed.ic.KPzuH4J-TG.png)
Oscilloscope clip must be clamped to chassis or large heat sink mounted with 7 pairs transistors.
![Broken! :-BROKE](https://www.eevblog.com/forum/Smileys/default/smiliey_scope_broke.gif.pagespeed.ce.z9RuKVWKjY.gif)
Different chips may be used, locate them and searching them on web so as to probe pins concerned.
![Broken! :-BROKE](https://www.eevblog.com/forum/Smileys/default/smiliey_scope_broke.gif.pagespeed.ce.z9RuKVWKjY.gif)
Steps sent to you is a shortcut to distinguish which part of the digital circuit goes wrong.
![Cool 8)](https://www.eevblog.com/forum/Smileys/default/xcool.gif.pagespeed.ic.cOxV6sPNRd.png)
Do not ask me why and no principle involved. At least 3 pages essay needed to explain principles, otherwise.
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
Digital board is the most difficult part in an av-amp.
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
A logical thought and sturdy knowledge is required.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/xwink.gif.pagespeed.ic.cldandycH0.png)
No only hardware
but also software make it no sound.
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
This explains why no one is able to or dare to troubleshoot an av-amp digital board in
Hong Kong,
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
even authorized service department,
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/xfacepalm.gif.pagespeed.ic.EBDwh1hCfo.png)
let alone Sham Shui Po, Apliu Street.
Steps involved are top-secret and do not take tech for granted he/she tells you how to do or even gives you a hint/hints.
In Hong Kong, authorized service department, told you to replace the digital board with $3480HKD = 447USD
BTW, direct sound can give a clue to you only if there are some speaker relay indicators on front panel such as onkyo.
Using this method to diagnose will , however, not help you.
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/xsmiley.gif.pagespeed.ic.R8GFI-pF6f.png)
Your amp does not have debug mode to diagnose digital problem.
Don't worry. Steps I have told you suitable for onkyo, yamaha, anthem, sherwood and pioneer.
![WTF? :wtf:](https://www.eevblog.com/forum/Smileys/default/wtf2.gif.pagespeed.ce.pxLiY5pjs4.gif)
Tell me the results if you want.