Defective CT5160

This “Cambridge SoundWorks DeskTop Theatre 5.1 DTT2500 Digital”, “Creative Desktop Theatre 2500” or CTT2500, is a reasonably priced Dolby Digital decoder. But after some 1000 working hours, especially on warm places, it shows a series error:

Most Common Error

You will probably guess it right, it is a defective electrolytic capacitor.

How to find

The mute signal is fed by the digital part of device. There sits a microcontroller that crashes sometimes or later permanently. But the only reason that is user-fixable is a defective power supply. Because you cannot track bugs in a (closed-source) microcontroller. The controller is on the upper board:
Somewhere on this board is the error; click on picture to see PCB's bottom side

Repair

Desolder the shielding plate first. Near the voltage regulator is C218, 22 µF, where you can measure 3.3 V DC (which is fully OK) and 0.5 V AC (too much). The capacitor has a too high ESR! Typical for too small and warm-situated polarized caps.
Here is the capacitor C218
The actual capacity is quite out of concern, I replaced it with 220 µF and it works too. — The C224 buffers the 5 V input for the voltage regulator.

That's all! (smiling)

Other Errors

Scratchy Volume Knob

Use cleaning spray for potentiometers.

Mutings on Volume Peaks

Another problem of power supply. You will experience a complete reboot with flashing LED lights.

In this case, the capacitor in the external power supply unit is defective. Replace it.

Upgrades

Possible: