Wharfedale Titan 12 Active power supply problem?

[am911]

Hi, I have a problem with a Wharfedale Titan 12. When I turn it on after a long period off, the only thing it does is a big 'POP' coming from the woofer. After that nothing like dead. When I trun it On and Off and ON, I hear no 'POP' but it is allways like dead.
Anybody seen this problem? I suspect the power supply.

[am911]

By the way, sorry if I posted on the wrong thread

[Jazz P Bass]

The problem could be in the power supply.
Then again it could be in the power amp itself.
'Seeing a problem' that others have had is not much help.
You need to open her up & troubleshoot the problem.

[km6xz]

The only thing to add to what Jazz P Bass said is to not turn it on with the speaker connected to the possibly faulty amplifier/power supply. The loud pop could damage the woofer which would be much more expensive to repair than just the amplifier or power supply section.

Do you have any test instruments? Open it up and disconnect the woofer and leave it disconnected until you are sure the amp is ok. This unit uses a switch mode power supply which can be dangerous to trouble shoot if you are not really familiar with them, and have an isolation transformer. The amplifier section is a Class D, so-called Digital Amplifier that has few of the normal waveform conventional older amps have, so again, troubleshooting will require test instruments and a good working knowledge of how a Class D amp works.
I would strongly suggest seeking the help of the nearest Wharfedale warranty station repair shop unless you really know switching power supplies and Class D amps. As a side note, Class D amps are very reliable and seldom fail but their switch mode power supplies do fail and is the most common sort of problem with this type of circuit. Your average tube guitar tech down the street will not be a good source of help on these.

[paleeman]

Does the standby LED remain lit after the "pop" ? If so, then the amp is dead. If not, then the power supply is faulty. Anyways, I also do not recommend repairing it without proper test equipment and a basic knowledge of SOPS and D-class amps. You'll just end up damaging it more.

[allanlaw1]

I have the same. Problem. Mine happend on low volume a few weeks back . I jus happen to notice that my blue led indicator was off. When I went to switch it on , the same pop sound and then nothing. After a short while I turned it on again and the same happened. I opened up the back (warranty was up) . Nothing was burnt , no odd smells, just dead. The other speaker was perfect. One thing however, this same speaker had the tendency to cut off from time to time.

[diydidi]

Check the power amp woofer mosfets first.

[plec.22]

same fault as above on pro12...o/p fets no shorts there how ever the unit will quick power up then off.

[diydidi]

On these the smps usually fine. The power amp woofer section usually goes faulty. Replace fets and class D driver board. It is a SIP module. On "D" type models, replace class D chip.

[plec.22]

More checking last night found over heated 10k resistor within psu..fets ok...Just need schematic to see whats going on here...

[Jazz P Bass]

Wharfedale Titan Active 12 schematics

Here are the schematics that I have.
Bear in mind there are two versions.
The A & the D.

[plec.22]

Thank you for schematics Jazz bass, it makes things clear to see what's going on instead of cold checking the 'see it on the board parts'...it's still on the table in bit's just now. will look over things later to start voltage checks..I would say it try's it's best to quickly power on tho.

Also to add this one is the old gray cab..

[plec.22]

This one is class d amp...

[diydidi]

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

[lamouche1]

i got the same speaker here rev. A the problem began with no power at the woofer with small output on the high frequency speaker i got a weird noise over the audio frequency then during testing i lost everything no burnt fuse only no more voltages on dc side on ac side of the transformer the voltages looks normal.