Hello everybody , i have a problem with my f4 amplifier.My right chanel the dc offset when i turn on i have -70mv and after 3 hours is near 0mv , but with my left chanel i have some problems when i turn on everytime i have different value and and goes up and down very fast and the las value was from 86mv to 120mv in 10 minutes.
Thx for help, greetings from Romania.
Thx for help, greetings from Romania.
as I said in PM - post pictures
double check mounting of outputs on heatsink - are they tightly & evenly screwed on heatsink , check all solder joints (including all resistors in biasing network)
replace TL431 - it's cheap anyway
luckily - your problem isn't connected to input Jfets in any way 😉
double check mounting of outputs on heatsink - are they tightly & evenly screwed on heatsink , check all solder joints (including all resistors in biasing network)
replace TL431 - it's cheap anyway
luckily - your problem isn't connected to input Jfets in any way 😉
I had similar problem caused by P2 trimpot (500 ohm). Change it then. Besides I noticed that it's very easy to set DC offset very close to zero within range of -3 to +3mV or smaller. If problem still exist replace TL431 as Zen Mod said.
After a new 5 kohm trimpot nothing change, i changed also the TL431 same problem.
What can i do , other changes?
What can i do , other changes?
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