Wharfedale Titan 12 Active power supply problem?

[paleeman]

Too many failures? MAybe, but most amp models are discontinued due to insufficient sales.

In this case, I'm quite certain, because the active loudspeaker itself was not discontinued, it is kept in production, but fitted with another amp. (Which is, so far, so good)

[paleeman]

That is a perfectly good way to put it! If English is not your first language it might as well be; thank you for sharing your knowledge!

Thank you, this means a lot to me.

[jangles]

No sound from woofer.

In this case, I'm quite certain, because the active loudspeaker itself was not discontinued, it is kept in production, but fitted with another amp. (Which is, so far, so good)

Hi Guys,

I am trying to repair a Titan 12 Active which someone else couldn't fix. It appears they changed Q17 to IRFP250N and Q17 to IRFP4229.

The tweeter circuit is working and I get sound from the tweeter but not the woofer. The woofer tests good (4ohm VC)

For voltages on Q17 I get:
G -.186v
D 69.2v
S -.182

Q18
G -69.2v
D -.182
S -69.3

I'm not too familiar with mosfet class D designs but I know some of the basics.... Q18 voltages don't seem right? any advice. I do have a scope and test equipment.

Any suggestions are welcome.

Thank you,

Jangles

[nickb]

Hi Guys,

I am trying to repair a Titan 12 Active which someone else couldn't fix. It appears they changed Q17 to IRFP250N and Q17 to IRFP4229.

The tweeter circuit is working and I get sound from the tweeter but not the woofer. The woofer tests good (4ohm VC)

For voltages on Q17 I get:
G -.186v
D 69.2v
S -.182

Q18
G -69.2v
D -.182
S -69.3

I'm not too familiar with mosfet class D designs but I know some of the basics.... Q18 voltages don't seem right? any advice. I do have a scope and test equipment.

Any suggestions are welcome.

Thank you,

Jangles

I recommend you start a new thread to avoid confusion - this thread deals with a different problem - well probably. You can't measure voltages like that in a class D amp since everything is pulsing - you need to use a scope. You can only meaningfully measure across the speaker output.

[Gladi]

Take the two woofer mossfets out.Power on and report back.

Hi Diydidi
I have same problem with this speaker, when I turn it on heard big 'POP' coming from the woofer and then dead, I opened and see two resistor R32 & R7 over heated at the first.
I changed U9 (IR2011) on class D daughter board, nothing changed and finally I took the two woofer mosfets Q17 & Q18 same as you said, now is turn it on and I can see green led working.
could you please say what do you think ? mosfet transistors ? or something else ?
thank you.

[diydidi]

Hi Diydidi
I have same problem with this speaker, when I turn it on heard big 'POP' coming from the woofer and then dead, I opened and see two resistor R32 & R7 over heated at the first.
I changed U9 (IR2011) on class D daughter board, nothing changed and finally I took the two woofer mosfets Q17 & Q18 same as you said, now is turn it on and I can see green led working.
could you please say what do you think ? mosfet transistors ? or something else ?
thank you.

Hi.
Replace the 2 Mosfets.

[Gladi]

Hi.
Replace the 2 Mosfets.

thank you
i will do it and write back here the result.

[Gladi]

Hi.
Replace the 2 Mosfets.

Hi again
many thx Diydid, it's fixed with ur help.
first changed MOSFET driver (U9) if didn't fixed change the 2 MOSFETS (Q17,Q18).
Cheers.

[MojoAmpGuy]

I am struggling to diagnose a Titan 12 Active speaker issue. Unit powers up. yet no output signals.

Power supplies

+15 v = +15v
-15 v = -15v
+35v = +35v
-35v = -35v
However
+70v = 58v
-70v = -58v

Does anyone know why the +/- 70v rails are measuring low?

P.S other key measurements

Mute measures -15v
Protect to negative rail measures 0v.

output FET’s appear OK

Running out of ideas. Any suggestions welcome.

[Enzo]

Hi Mojo. May I suggest you start a new thread for your amp. This thread is four years dead and is about a different unit.

And if you have a schematic, could you then post or link it?