Hi all,
I changed mine 1084s' EHT few months ago and then monitor started blown away the TDA7052 sound amplifier/opamp chips.
I tried these list until now:
- Simply cleaned volume knob's potentiometer and all other pots with contact cleaner,
- Replaced potentiometer from two constant resistors, becuase i dont have stereo (dual) potentiometer for opamp's signal level input,
- Changed faulty opamps with new ones, they are blown again,
- Checked V+ of opamps, there are 9V of this point, its normal value from service manual,
- Changed caps around signal and DC supply path of 7052's, dont resolved,
- Measure voltage across thick steel like GND line cabling frame around CRT tube and wall mains N line and read around 42v AC, is this normal or not? (is this degaussing line?) I think this can be inducing wirelessly due to high voltage of CRT but not sure about this,
- Check other GND lines in PCB, some is continue to main GND point in AC mains socket, some not; some are connected betweeen, some not. I cant be sure about GND circuitry from service manual,
What should i do from now on? I think i should check the mains - live power supply part of monitor but i dont know about much these stage of circuit.
Can anyone help me please? Thanks.
I changed mine 1084s' EHT few months ago and then monitor started blown away the TDA7052 sound amplifier/opamp chips.
I tried these list until now:
- Simply cleaned volume knob's potentiometer and all other pots with contact cleaner,
- Replaced potentiometer from two constant resistors, becuase i dont have stereo (dual) potentiometer for opamp's signal level input,
- Changed faulty opamps with new ones, they are blown again,
- Checked V+ of opamps, there are 9V of this point, its normal value from service manual,
- Changed caps around signal and DC supply path of 7052's, dont resolved,
- Measure voltage across thick steel like GND line cabling frame around CRT tube and wall mains N line and read around 42v AC, is this normal or not? (is this degaussing line?) I think this can be inducing wirelessly due to high voltage of CRT but not sure about this,
- Check other GND lines in PCB, some is continue to main GND point in AC mains socket, some not; some are connected betweeen, some not. I cant be sure about GND circuitry from service manual,
What should i do from now on? I think i should check the mains - live power supply part of monitor but i dont know about much these stage of circuit.
Can anyone help me please? Thanks.
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