I have a full distortion from right channel.
From the voltage and signal trace I did I discovered that there is no output voltage and signal from 496 diode.I changed the diode but still nothing
I swapped the transistors tr45 46 47 50 from the other channel but still nothing.
I swapped the input signals cables which goes to amplifier pcb and again nothing changed
I put new power supply capacitor and didn't do anything
Tr46 has voltage on emmiter and base but not in the collector
Here is the schesmatic marked with no output
I can't find any solution to my problem
Any help would be appreciated.
Thanks
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Beomaster 3000-2 heavy distortion from right channel
31 replies
It sounds like TR46 is not being turned on. Are the voltages on its base and emitter as per the diagram?
It's not tr46 cause I swapped from the left channel and still nothing..
The commiter still has no output voltage while base and emmiter has..
You misunderstood my suggestion. If the voltages are not as specified in the schematic the transistor will not turn on even if it is good. What are the actual base and emitter voltages?
Hello Mark.
The voltage in left good channel is around 22 on input diode and on right is 27 voltage.more close to factory.
BUT this transistors are only for current protection. As the manual says.When I removed them the left channel had still voltage on diode output.
Btw base voltage 28.6 emmiter 29 collector 0
It's possible you have a broken trace at the anode of the diode. Try a jumper from it to the base of TR47 and the collector of TR46. Don't know what else to suggest based on what you are reporting.
Hello.
Thanks for your interesting.
There is no voltage on anode leg of diode.i swapped two times with new but still nothing.
The trace is ok
I did a bridge between input and output of diode and I measured a significant voltage drop on the collector of tr50.Without the jumper the voltage was around 28 volt.
With jumper it went to 5 volt!!
Base volt was exactly 0.5volt
Any thoughts on that?
The diode is blocking current flow from TR48 collector to base of TR47 as it conducts in the other direction due to the higher voltage that is supposed to be on the base. Therefore, it cannot be bypassed with a jumper.
You say there is 0 volts on the anode, is it the same at the collector leg of TR46 and the base leg of TR47? If you power down, what is the ohms reading to ground from the anode for each channel?
Exactly it's 0 volt on two transistors as you describe..I check the traces and everything is fine.i will make the meausurement on diode tomorrow to see the results
Btw I tried to put voltage from base of tr46 on tr47 and i read 3 volt on collector of tr50.Without this voltage the collector goes around 29v.
Why is this drop assuming that the base should have this voltage?
THANKS
Anode right channel 568 kohm.
Left channel 590kohm
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