Hello,
I have this receiver from Onkyo that I got from a friend. My friend during the installation short circuited the center channel output. After that the channel works during a few minutes and then start to fall down until it is completed muted.
Besides my graduation in electronics, audio is really not my business but I like to do my own fixing and projects in available hours so I started investigating this problem and I'm willing to change the output stage transistor but I'd like to hear some advises from the forum.
The crop of center channel output stage circuit is in attached picture. To be honest, I don't know if the problem are in the transistors or not. I have done some voltage measurements in bias resistor and they are according to specified in service manual: 2.5mV just after turned on and about 10mV after 4~6 minutes heating, all without load.
Any ideas?
thanks!
I have this receiver from Onkyo that I got from a friend. My friend during the installation short circuited the center channel output. After that the channel works during a few minutes and then start to fall down until it is completed muted.
Besides my graduation in electronics, audio is really not my business but I like to do my own fixing and projects in available hours so I started investigating this problem and I'm willing to change the output stage transistor but I'd like to hear some advises from the forum.
The crop of center channel output stage circuit is in attached picture. To be honest, I don't know if the problem are in the transistors or not. I have done some voltage measurements in bias resistor and they are according to specified in service manual: 2.5mV just after turned on and about 10mV after 4~6 minutes heating, all without load.
Any ideas?
thanks!
Attachments
I would look very hard at the associated output protection relay there. Sounds like it may have contact issues.
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