Power indicator, directly connected to the loudspeaker amp output.
Works up to the 5-th led and the five remaining glow at once, right from the start ..
Have to check the transistors or smth else is messed up 🙁
Works up to the 5-th led and the five remaining glow at once, right from the start ..
Have to check the transistors or smth else is messed up 🙁
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Do you have a make/model and a schematic? does the amplifier work as normal otherwise? Something failed/shorted in the display circuit.
Forgot the schematic
D3, D4 not mounted (bridge), C3, C4 not mounted, so it should be x2 voltage multiplier.
Mby it is still too sensitive and I can increase R2...
The amp is ok
D3, D4 not mounted (bridge), C3, C4 not mounted, so it should be x2 voltage multiplier.
Mby it is still too sensitive and I can increase R2...
The amp is ok
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I have no idea how the circuit is supposed to work, but you could check if turning trimming potmeter RP1 helps. Preferably note the present setting somewhere, so you can get back to the original setting if it doesn't help.
The led ladder is in series, so when enough current is applied, all the LEDs glow the same intensity.
Then the transistors ladder shortens the LEDs. When the voltage gradually increases, the transistor shuts off base collector and the current goes through the led instead of the transistor.
If the voltage is low, the transistors are open.
If there is no transistor/ toast transistor - transistors are 'closed' and led glows.
The (5-th) transistor was toast breaking the transistor ladder, so all the next transistors were closed.
I put the transistors 1 to 9 and it works.
The strange thing is that the end transistor missing causes the TWO last LEDs to glow...
Then the transistors ladder shortens the LEDs. When the voltage gradually increases, the transistor shuts off base collector and the current goes through the led instead of the transistor.
If the voltage is low, the transistors are open.
If there is no transistor/ toast transistor - transistors are 'closed' and led glows.
The (5-th) transistor was toast breaking the transistor ladder, so all the next transistors were closed.
I put the transistors 1 to 9 and it works.
The strange thing is that the end transistor missing causes the TWO last LEDs to glow...
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