Microelectronics | Cambridge Audio DacMagic 100

Synopsis

I decided to replace the junk Fujicon electrolytic capacitors in this digital to analog converter. The operation should be insanely easy given the low electrolytic capacitor count. The problem is that most of them have at least one pin soldered to either the ground or a power plane. This requires a very powerful soldering iron since the planes sink a lot of heat. I used a 360 degrees Celsius thermoregulated soldering iron for the job.

Disclaimer
This article is not to be treated as a do-it-yourself tutorial on how to fix, restore, rebuild, or improve this unit. This was not my initial intention. But you can consider this whole content as a general guideline, should you decide to attempt any service procedure on an identical or similar unit.

The entire documentation is just a reflection of my work and I cannot be held responsible if you damage your unit, or even harm yourself in the process.

Maintenance

I used Nichicon PWM series capacitors for the supply filters and Nichicon Muse BP for the audio outputs.

I absolutely hate working on cheap China PCBs soldered with RoHS solder. While this PCB quality is acceptable, the solder used on this one is no exception. I always use eutectic solder for my DIY projects and things go well. However, I had to use high purity acetone to clean the flux on the PCB. The original assembly was a very dirty job and I feel that some parts were hand soldered as there were soldermask scratches and solder blobs all over the place. The old flux is the worst I've ever seen. Smells badly and responds little to 99.99% isopropyl alcohol. Thus, acetone is the name of the game. Stinks but gets the job done in a timely manner.

How about the sound? A little bit more open on the higher end of the spectrum. But I suspect the MUSE BP parts for this improvement. Don't get me wrong, this DAC sounded OK before the capacitor replacement. But I feel it's better now. Construction-wise at least.

Pictures

Here are some pictures that I took during this operation.

There is a fair number of test points on the solder side. Also, the copyright text alignment is a bit funky. Otherwise, the PCB looks OK.

Overall, the layout of the PCB screams this being a consumer product. It's good, but attention to detail is not its strong point.

Hopefully this DAC will hold forever as I am very happy with how it performs.