Hi, can anyone help me to identify the values of L400 and L402 inductors on the Logitech Z-2300 motherboard? they are located near TDA amplifiers. Thanks in advance.
Well because I needed to replace a bad TDA7296 amplifier, but on the PCB there were lots of glue. While I tried to remove metal plate which pins all 4 of the TDA amplifiers to the radiator (which was also glued to the PCB) , I accidentally removed it with the glue and in it were two inductors.... so now I need to find their nominals so I could replace them...
I can't see any components on your picture that look like inductors. It would have helped if you had said that this was an amplifier rather than describing it as a motherboard. I assume others (As I did.) assumed you were talking about a computer mother board.
Edit. After seeing Nigel's reply It looks like the option of fitting these components was not used. What is the fault an you equipment ?
I can't see any components on your picture that look like inductors. It would have helped if you had said that this was an amplifier rather than describing it as a motherboard. I assume others (As I did.) assumed you were talking about a computer mother board.
Edit. After seeing Nigel's reply It looks like the option of fitting these components was not used. What is the fault an you equipment ?
Sorry if I have mistaken you, but you get my point now and that's what matters.
I had one faulty output channel (left speaker didn't work) and I have found one defective TDA7296 amplifier. In order to replace it I had to remove metal plate that I mentioned earlier. And that's how I have damaged these inductors
Exactly, this is a small toroidol inductor with ferrite core.
I think that these form a RLC low-pass filter. So the audio signal comes from dual operational amplifier (4565 IC) then passes the RLC low-pass filter and afterwards travels to TDA7296 amplifiers input. So if I would replace these small inductors with a peace of short wire, wouldn't the signal be distorted?
I can't see any components on your picture that look like inductors. It would have helped if you had said that this was an amplifier rather than describing it as a motherboard. I assume others (As I did.) assumed you were talking about a computer mother board.
Edit. After seeing Nigel's reply It looks like the option of fitting these components was not used. What is the fault an you equipment ?
Exactly, this is a small toroidol inductor with ferrite core.
I think that these form a RLC low-pass filter. So the audio signal comes from dual operational amplifier (4565 IC) then passes the RLC low-pass filter and afterwards travels to TDA7296 amplifiers input. So if I would replace these small inductors with a peace of short wire, wouldn't the signal be distorted?
No, there's no need for the inductors, as shown on the datasheet.
I would imagine they are there to help reject any strong RF signals (for if you live next door to a big transmitter), and FAR too low a value to affect audio in any way.
The Logitech Z-2300 speaker system has a subwoofer and two low power satellite speakers. The TDA7296 amplifier ICs drive the satellites with mid-range and high audio frequencies. Maybe the inductors are part of the crossover frequency dividing system (high-pass filters, not low-pass filters). Without a schematic we are just guessing. If the inductors are part of the crossover then removing them will cause low frequencies to destroy the tweeters.
The Logitech Z-2300 speaker system has a subwoofer and two low power satellite speakers. The TDA7296 amplifier ICs drive the satellites with mid-range and high audio frequencies. Maybe the inductors are part of the crossover frequency dividing system (high-pass filters, not low-pass filters). Without a schematic we are just guessing. If the inductors are part of the crossover then removing them will cause low frequencies to destroy the tweeters.
I have made audio equipment for radio stations. The RF fields are strong and cause strange things to happen in some audio amplifiers. I use ferrite beads to remove the RF. If this is the case then just short out the coil. (solder a piece of wire across the coil)