Fixing my DTT3500

For years I am using a great 5.1 speaker system: Cambridge SoundWorks DTT 3500. It was quite expensive at the time when I was buying it, but it is still playing really great nowadays. Of course it is not a top product for audiophiles, but the sound quality is totally sufficient as a 5.1 speakers to the Kodi media center in my living room. To be able to use it with my new PC, I had to switch my source from original Digital-DIN (Creative-only audio cards, like SB Live/Audigy) to more general and wide used: optical output of my Asus mainboard.

Unfortunately when I switched to optical a new problem occured. The amplifier had to warm up before it was playing correctly. When I powered it up it was crackling and the Dolby Digital indicator LED was blinking. The playback settled down usually after about 3-5 minutes. When the amplifier was warmed up, cycling power doesn’t do any harm – it was ready for work. I was suspecting the capacitors.

Happily google helps me a lot with this issue: I found this forum thread on Overclockers Forums:

This was it! The guys have identical problem and a cure for it!
Under the Faraday cage three capacitors needs to be replaced.
I decided to buy and replace those three capacitors.

First I was searching for these capacitors at TME, but all of them was too high to fit under the Faraday cage (it has to be low profile, 7 mm max).

Fortunately the guys on the forum also provided a part numbers for some popular electronic online stores.
After some basic research i decided to go with Farnell element14.
I ordered the following capacitors:

The shipment was really cheap: 16PLN (considering the package was from UK to Poland). And what was really cool: I have the package next day after placing the order!

I was ready to start the process. The forum thread has many information, tips and photos which was really helpful. Nevertheless I will provide also mine photos from the work. Maybe you will also find it helpful if you are in the similar situation 🙂

Including assembling, the whole work took me about 3-4 hrs. I was not disassembling the main volume knob so I had to be careful about a wire which was constantly connected to it.
As I suspected, I had some small problems soldering out the Faraday cage. I was using a hot air tube for this but the board resisted much (and was also deforming a little when I was trying to pulling it out), but finally I’ve made it – it was also probably because some kind of glue on the soldering pads. The capacitor replacement was much nicer; soldering the cage back was the easiest task.
As you can see on last photos I have another one capacitor leaked, but due to the fact that I was not prepared to replace this one – I just leave it untouched – so far without any harm in my case. I can also see that this capacitor is bad eg. here on the following pics:

… so this seems to be another general problem with this hardware.

After reassembling and connecting back to speakers, there was a moment of truth.
Fortunately – the operation went successfully – no crackling, Dolby Digital LED still green – all is working great!

Before, it was really annoying when I had to power it up, then go somewhere waiting until it stop crackling, go back and use it.
Finally I can now power up my amplifier whenever I want and just start use it immediately! This is really awesome!

Big thanks for guys from Overclocker Forums!

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