My marshal amp recently stopped working so I decide to fix it. I replaced the main amp chip a TDA 7293 along with all of the other pre amp chip including many TL027`s when I put the amp on now it works all of the time but is very quiet? Can anybody shed light on my problems? I also noticed two leds in the amp one green and one red, are they for test purposes? should they light up?
Cheers for any help offered
Cheers for any help offered
Look at pin 4 of the module ribbon, or pin 9 of the 7293 itself. This is the standby pin. There should be a positive voltage there - maybe 3-5v or something. When the big chip fails sometimes it damages the mute circuit.
On the main board somewhere is a small transistor and a zener that control this line. Shorted zener will leave the chip muted.
Something to check.
On the main board somewhere is a small transistor and a zener that control this line. Shorted zener will leave the chip muted.
Something to check.
- Status
- Not open for further replies.