HI,Hi guys, I'm a newbie to this forum and am looking for help to find out what's wrong on a circuit. I have been using the Creative Inspire 5.1 PC speaker system for almost a decade. Sadly it stopped working about a few months back. There is a volume and bass control pod which sits on the desk, and when it stopped working, the green led light on it would not turn on.
My knowledge in electronics is very limited, but I'm a hobbyist willing to learn. So I took it up as a project to restore this system. Over the last few months I have done the following checks on it and somehow brought it upto some stage where the green light on the volume control pod now turns on. But however, there is no sound output coming from the 5 satellite speakers or the subwoofer.
Things I have checked and done so far include :
- Checked the fuse on the circuit - it was ok
- Checked the power source, which is an external transformer providing AC current at 13.5 volts @ 5 amps - both voltage and amps were good.
- Checked the DC power conversion stage of the circuit - voltage and amps were good here as well.
- Proceeded to check transistors, diodes and zener diodes. Found 1 shorted Zener Diode (C11) and two shorted transistors (H945) all of which were promptly replaced - However the green LED light would still not turn on.
- Then I replaced the op amps (1 4556AD with a 4556D and 5 MC4558CNs with 4558Ds) - still no sign of green light turning on
- I proceeded to replace the 3 volume control ICs (M51132L) and lo and behold the green light now turned ON. However there was no sound output.
- Thinking it is something wrong with the 2 audio amplifier ICs (TDA8947J) I have replaced them as well (these were the last of the components leaving aside caps and resistors that i have not replaced on this board). Im still not getting any sound output.
I think I have hit a wall and am scratching my head all over. Which is why I'm looking to this forum for help. I have noticed that now when I turn on the circuit the highlighted Zener Diode and 4 transistors all go hot within a minute or so (see pictures attached). This so happens to be the Zener Diode that I have replaced which was previously shorted. I am not sure what is going wrong.
I have seen a previous thread (http://forum.allaboutcircuits.com/showthread.php?t=39747) with a similar outcome like mine - no green light and no sound. Yet somebody managed to help the OP with his problem. I wish I had that insight to figure out what's wrong here - the kind of knowledge that let you isolate areas of circuit take measurements and figure out which components were bad, rather than having to replace all of them and still get no sound output.
thanks and regards,
please can you help me? I spend lot of days browsing internet to find some solution. I have broken Creative Inspire T5900 speakers. Your PCB look almost like PCB from my speakers (with some exceptions). I have measured all the components except the zener diode. If you know, can you tell me parameters of zener diode. I hope speakers works after replace damaged components.
Moderator edit: New thread created from old thread: