Hi guys,
I was working on this Onkyo amp which had a shorted channel. One of the power NPN transistor had shorted out and one half of the noble resistor was also open. (I made a previous post about transistor replacement). Anyway I took the two power transistors and the noble resistor from a working channel that is not used. Amp was working perfectly when I tested it. I should ask is it ok to leave the unused channel without the two transistors and the resistor?
Ran it for sometime I heard a relay click after a while not sure which one it was - no error message nothing and the amp kept on working. Turned off and on again no problem was working.
So I took it to its owners place and I wanted to check whether the speakers had shorted as this was my suspicion for the original failure.
He had two tower speakers - I measured across the terminal (it has got a filter circuit) and here is something peculiar I found:
1.Left speaker measured in the mega ohms range right away.
2.Right speaker showed the numbers crawling up in other words I saw the capacitor charging, and I heard the woofer move when touched with the DMM.
The owner was using it for sometime and he called me back saying the amp had died again. From what he described I know that the fuses on the B+ voltage rails had blown and the amp didn’t have time to go into protection mode.
So guys am I right in thinking the speakers might at be at fault here. I am going there tomorrow to see whether the same channel had shorted out.
Any adivce/tips on the matter would be greatly appreciated.
I was working on this Onkyo amp which had a shorted channel. One of the power NPN transistor had shorted out and one half of the noble resistor was also open. (I made a previous post about transistor replacement). Anyway I took the two power transistors and the noble resistor from a working channel that is not used. Amp was working perfectly when I tested it. I should ask is it ok to leave the unused channel without the two transistors and the resistor?
Ran it for sometime I heard a relay click after a while not sure which one it was - no error message nothing and the amp kept on working. Turned off and on again no problem was working.
So I took it to its owners place and I wanted to check whether the speakers had shorted as this was my suspicion for the original failure.
He had two tower speakers - I measured across the terminal (it has got a filter circuit) and here is something peculiar I found:
1.Left speaker measured in the mega ohms range right away.
2.Right speaker showed the numbers crawling up in other words I saw the capacitor charging, and I heard the woofer move when touched with the DMM.
The owner was using it for sometime and he called me back saying the amp had died again. From what he described I know that the fuses on the B+ voltage rails had blown and the amp didn’t have time to go into protection mode.
So guys am I right in thinking the speakers might at be at fault here. I am going there tomorrow to see whether the same channel had shorted out.
Any adivce/tips on the matter would be greatly appreciated.