Hello, Can anyone help with me on this.
I have an old JVC AX-1100 BK amp . This is not working for a very long time. I found the protection Led do not stop blinking and so the speakers do not get connected. I have checked most the related circuit but could not find any specific fault. One problem with this unit is tracing the wiring. Have any one encountered similar issue with this amp?
I have an old JVC AX-1100 BK amp . This is not working for a very long time. I found the protection Led do not stop blinking and so the speakers do not get connected. I have checked most the related circuit but could not find any specific fault. One problem with this unit is tracing the wiring. Have any one encountered similar issue with this amp?
Hello, there is a protection circuit with IC 601 TA7317
are pins 2 and 3 of IC 601 at ~ 0V ?
Power rails voltages ?
There must be some cause TA7317 is not turning the speaker's relay, like you should find some voltage on some pin that is not right.
If the protection circuit is at fault (all DC voltages are good) then you should confirm that both channels are working properly with an audio signal at the input and a speaker connected (strongly recommended through an unpolarized high voltage capacitor) at the power amp output: between ground speaker terminal and -( m )- at the connector RT501 and between ground speaker terminal and -( n )- at the connector RT502.
Again check DC voltages between -( m )- , -( n )- and ground speaker terminal are 0 V first !
Is the DC output of power amplifiers, pin 6 of IC 501 and pin 6 of IC502 at ~ 0V ?
are pins 2 and 3 of IC 601 at ~ 0V ?
Power rails voltages ?
There must be some cause TA7317 is not turning the speaker's relay, like you should find some voltage on some pin that is not right.
If the protection circuit is at fault (all DC voltages are good) then you should confirm that both channels are working properly with an audio signal at the input and a speaker connected (strongly recommended through an unpolarized high voltage capacitor) at the power amp output: between ground speaker terminal and -( m )- at the connector RT501 and between ground speaker terminal and -( n )- at the connector RT502.
Again check DC voltages between -( m )- , -( n )- and ground speaker terminal are 0 V first !
Do you mean on the JVC AX-1100 schematic, or on the actual unit ?
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Thank you for the reply . I shall check the voltages as you mentioned and revert back. For the time being I have kept it aside due to other works. I shall look into it again after a couple of days.
"Do you mean on the JVC AX-1100 schematic, or on the actual unit ?" - Both.
I had changed the op-amp comparator ic, since it was not functioning as it should. This changed one issue - earlier there was high negative voltage almost every where on the output side of one channel. Now that is not present. But still doesn't work (Speaker relays do not get activated).
One more symptom : earlier it shows some increase in bias voltage when volume is increased for about a minute and then negative voltage gets flooded everywhere on one side. But the other side - nothing happens - no negative voltage , not bias voltage increase etc.
now both shows same.