Repairing a CLIO "clearview" audio device

[k1mgy]

A friend handed me his broken Clio.  This is a nifty stereo speaker device that uses an curved acrylic panel, driven by what appear to be piezo-based transducers for left and right channels.  It also has a ported subwoofer in its base.

It was claimed that only one channel was operating.  Indeed, testing revealed this to be so.  Furthermore, at idle, the unit was drawing >500ma, which seemed strange.

After disassembling I found two mylar capacitors at the broken channel (approx sizes 2512 and 1206), and both appeared to have leaked out their goodness.  One of the nearby traces was eaten away.  There are two others at the working channel, and these measured 10nf and 1.5nf in circuit.  But not trusting an in circuit test I tried to desolder and remove these.. and of course managed to destroy both.

No parts list or schematic can be found. 

I'm guessing the output circuit is specific to driving a piezo transducer... but never having done so with audio, it's difficult to know what values of capacitors might work here.

[DaJMasta]

If they're just AC coupling the signal path, then bigger means better low frequency response - sometimes these last coupling caps can be tens or hundreds of microfarad, but usually a few to ten is sufficient (depends on the impedance of the device they're driving, which varies with frequency).

If you have an LCR meter, try measuring the speaker element at various frequencies to get an idea of the impedance, then you can plug that into a high pass filter calculator and get an idea, but if they're surface mount and actually are film caps (most surface mount caps I see are either ceramic or tantalum), they can't be huge values because film caps just don't go that high.

Now this would only count for one of them in each side, the other is probably for filtering and would need to be the right value if it actually is a film cap, but if it's a ceramic or something, it could just be for decoupling and any old value would do.


I would start by tracing out this portion of the circuit to see what it's functioning as, which should give you an idea of the ballpark values of the caps and how important it is to be right with the value.  In a lot of instances, larger is fine and won't hurt.