Bose soundtouch 30 woofer works tweeters do not

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

You are right.

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

I have just discovered that the smps shuts down if I signal trace the audio, when the woofer is working (with tweeter speaker disconnected).
I have another small amplifier which I use as a signal tracer, if I connect this to the audio in.
of the tweeter ic it gives good quality sound.
But if I connect this to the woofer ic audio in, the smps immediately shuts down.
This puts a small doubt in my mind about my thinking the tweeter ic is bad.

[budm]

Re: Bose soundtouch 30 woofer works tweeters do not

Do this, no speaker connected to either amplifiers, then use you audio trace at each pin of the speaker output connector, you will probably will not have sound on the Tweeter output connector pins, especially the one that shows 0VDC, you should get sound at both woofer output connector pins.
With output of 9V on one pin and 0V on another pin of BTL, that cannot be right, but you do not have to believe us. May be you should read up on how BTL circuits function.
BTW, you do have DC blocking/coupling cap at the input of the signal tracer amp. correct?
You also indicated that the woofer works just fine so why mess with it?

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

I have today replaced this ic , TPA31002d, but I am still not getting any sound in the speakers (tweeters) though now both sets of output pins show 7.6 volts with speakers connected.
Obviously the previous ic was defective.

As I had mentioned earlier previously the smps used to go to zero volts when speakers were connected, this is not happening now, with the new ic.
The woofer which is powered by another ic, continues to work.

I am able to trace the audio into the input of the ic TPA31002d.

[R_J]

Re: Bose soundtouch 30 woofer works tweeters do not

Check your solder connections, check the mute pin voltage is it high or low

[budm]

Re: Bose soundtouch 30 woofer works tweeters do not

check your solder connections, check the mute pin voltage is it high or low

+10

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

The fault and mute show zero voltage, the shutdown is showing 3.1 volts and Vreg shows 4 volts.

[R_J]

Re: Bose soundtouch 30 woofer works tweeters do not

Have you tried a different speaker?, those voltages look ok and the ic should be operational

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

Yes, the speakers are OK.

[momaka]

Re: Bose soundtouch 30 woofer works tweeters do not

The fault and mute show zero voltage, the shutdown is showing 3.1 volts and Vreg shows 4 volts.

Looks like the amp IC is working internally, then.

The only thing I don't quite find right...

I have today replaced this ic , TPA31002d, but I am still not getting any sound in the speakers (tweeters) though now both sets of output pins show 7.6 volts with speakers connected.

... is why now you're getting 7.6V on the speaker output pins. This prompts me to ask, what is the voltage on pins AVCC, PVCCR, and PVCCL.
With a BTL amplifiers, the voltage on the speaker output pins should be half of that of PVCCR and PVCCL, as we mentioned previously. 7.6V means PVCCL and PVCCR should be about 15.2V.

Other than that, also have a look at the resistor connected to pin ROSC. This is the resistor that drives the oscillator for the amp (as this is a class-D amp). Datasheet states this should be 100 kOhms, but the one in your speaker may differ. In any case, make sure its measured value matches the printed value on it (if value is higher than 5% of printed value, remove and check out of circuit).

Check voltage at pin VBYP - it should be 1.25V.

Also, if there are ceramic SMD capacitors (MLCC) connected between the following pins...
BSLP and LOUTP
BSLN and LOUTN
BSRP and ROUTP
BSRN and ROUTN
... make sure they are not short-circuited. I highly doubt you would find these capacitors to be the problem without the IC shutting down, but it's worth a check anyways.

Last but not least, make sure the voltage supply going to AVCC, PVCCR, and PVCCL is clean, as this is a class-D amp. If it's filtered by shady electrolytic cap brands, you might want to replace them with something else.

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

Thanks. The AVCC PVCCR and L show 23.6 volts.
The woofer, which is working, is powered by another ic, TDF8995B using same power supply has about 11 volts on the speaker terminals.
I will try to check the other points you have mentioned.

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

The woofer ic is "TDF8599B" not the one mentioned in my earlier message.

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

ROSC shows a resistance of 35K (the data sheet shows this as 100K) and a voltage of 1.7.
VBYP shows 1.2 volts.
I also cannot understand why speaker voltage (on all four pins) is 7.6, which I earlier thought was OK, but now understand should be half of power supply voltage.
MUTE and FAULT show zero volts and shutdown is about 3.1 volts.

[momaka]

Re: Bose soundtouch 30 woofer works tweeters do not

ROSC shows a resistance of 35K (the data sheet shows this as 100K) and a voltage of 1.7.

Well, the datasheet shows different resistance (100 KOhms), because apparently you can use this pin to set the oscillation frequency. So that may not be an issue. I was just checking to see if perhaps the resistance was very low (an order of magnitude lower) and thus making the IC not oscillate at the proper frequency (or at all).

You should check what resistor is connected to that pin, just to verify where that 35 KOhm reading is coming from.

VBYP shows 1.2 volts.

That looks okay as well. Datasheet says 1.25 V normally, but acceptable values are from 1.10 to 1.45V.

MUTE and FAULT show zero volts and shutdown is about 3.1 volts.

That seems okay. MUTE and FAULT should be low (or zero) if the device is NOT muted and there is NO fault. SHUTDOWN high to enable the device, which it seems like it is.

On that note, perhaps also check the voltage on pins MSTR/SLV. Just want to make sure this IC is not synced with some other IC, and perhaps that would be the issue.

I also cannot understand why speaker voltage (on all four pins) is 7.6, which I earlier thought was OK, but now understand should be half of power supply voltage.

Yeah, I'm trying to figure that one out too.
I know that for class AB amplifiers in BTL mode, the voltage should definitely be half of Vcc. Going by the subwoofer IC's voltages (also class D, it seems), we get half of the supply voltage. So why the tweeter IC doesn't have that voltage is indeed worrisome. If you can't find anything else, perhaps start removing all of the ceramic and electrolytic caps on the input and start checking them for leakage (resistance), in addition to checking ESR and capacitance, if you have the meter for that. Otherwise... maybe you got a dud replacement IC (unlikely, I know, but still possible).

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

Thanks, the MSTR/SLV and Gain 1 and Gain 0 appear to show zero volts. I have been unable to trace the ROSC resistor (supposed to be 100K, but was reading 35K) so far.

I only saw it connected to a very small capacitor, which I have removed.

[momaka]

Re: Bose soundtouch 30 woofer works tweeters do not

Thanks, the MSTR/SLV and Gain 1 and Gain 0 appear to show zero volts.

Interesting.
With the MSTR/SLV pin being low, that means the IC is set up to receive an external clock signal through pin SYNC.

That raises the question: is MSTR/SLV supposed to be low? And if it is, does the device it is synchronized with outputting proper clock signal? Certainly now this suggests that perhaps there may also be something wrong with another circuit on the board.

[spdy]

Re: Bose soundtouch 30 woofer works tweeters do not

Sorry I have delayed replying, I finally decided to substitute this with a small amplifier board using the same ic tpa3100d2, which costs only a few dollars, but ordered two from separate sellers, as one got lost.
Now this unit is working well. I removed the old ic completely.

[momaka]

Re: Bose soundtouch 30 woofer works tweeters do not

Yes, there are lots of cheap but decent amplifier boards on eBay and elsewhere online.
Good to hear you got it sorted out.