About capacitors - first I would check what is going on with C702 and 704, just to make sure they are good.
Hello Hirurgi,
thanks for the reply and tips.
I replaced all those transistors you mentioned and even replaced the 2 diodes. the 5 fusible resistors 100ohm and 10 ohm just to be sure. Also replaced 3 capacitors with same value and highrr
I also swapped the main outputs NEN/NEP 250 and 2sc5169 sip5 dual transistors from the rear left
fired on dbt, goes out of protection.
checked bias on front L&R amp board left channel at 11mA, right channel is fluctuating from 15-70mA but when it got warm it was at 1.2mA. The DC offset was -225mV for front right and 1mV for left channel.
there is sound but on front right channel it’s faint and not as loud as front left.
I double checked all the solder and cleaned the board with flux cleaner and soft brush. I was replacing a smd Q one at a time and there is no way you can put it wrong, unless the parts sent were not the correct ones. I did check each against the board and put the correct part numbers and tested on the transistor tester to make the npn and pnp are the correct ones for each Q #.
on btl 2 extra channel mode both left and right sound equal and good.
on normal 5 channel mode, the front right channel was the faint one and rest were fine there bias was all adjusted at 11mA and their dc offset were from 0-4mV.
I do know that the main output and sip5 transistors are good off or on circuit and while running with speakers there is sound on all 5 channels.
what did I miss? What is causing the right front channel to have a high bias and and high negative offset dc? I tested in circuit some of the smd resistors. Idk what else to check. Any suggestions would be appreciated.
thanks for the reply and tips.
I replaced all those transistors you mentioned and even replaced the 2 diodes. the 5 fusible resistors 100ohm and 10 ohm just to be sure. Also replaced 3 capacitors with same value and highrr
I also swapped the main outputs NEN/NEP 250 and 2sc5169 sip5 dual transistors from the rear left
fired on dbt, goes out of protection.
checked bias on front L&R amp board left channel at 11mA, right channel is fluctuating from 15-70mA but when it got warm it was at 1.2mA. The DC offset was -225mV for front right and 1mV for left channel.
there is sound but on front right channel it’s faint and not as loud as front left.
I double checked all the solder and cleaned the board with flux cleaner and soft brush. I was replacing a smd Q one at a time and there is no way you can put it wrong, unless the parts sent were not the correct ones. I did check each against the board and put the correct part numbers and tested on the transistor tester to make the npn and pnp are the correct ones for each Q #.
on btl 2 extra channel mode both left and right sound equal and good.
on normal 5 channel mode, the front right channel was the faint one and rest were fine there bias was all adjusted at 11mA and their dc offset were from 0-4mV.
I do know that the main output and sip5 transistors are good off or on circuit and while running with speakers there is sound on all 5 channels.
what did I miss? What is causing the right front channel to have a high bias and and high negative offset dc? I tested in circuit some of the smd resistors. Idk what else to check. Any suggestions would be appreciated.