Cambridge Audio DacMagic 2i repairs query

[Fizzy]

Hi,

Sorry if this is in the wrong section - admins please move as required.

Also not exactly an expert on audio or electrical circuits, so please bare with me...

I have a DacMagic 2i which I bought 2nd hand several months back. A month or two back it made a nasty "pop" and one of the analoque output channels went very quiet.....

To cut a long story short, it had blown a couple of capacitors on the board. (Or they had just deteroriated over the years).

Now I was not looking to do major updates to the unit as I have seen mention in various articles that popped up when I did various searches...just repair it so its working again.

Ok, the main culprit was the cap on the far right hand corner of the board (when facing the front of the unit) which looks like a smoothing cap, or at least the final stages of the audio output?

The other suspect ones where the two caps at the front left of the board, which look like smoothing caps for the power supply to the digital processing/switching circuitry?

The two power caps were "GL" branded, 3300mf, 25v, 85c. The audio stage cap is also branded "GL", and is rated 2200mf, 16v 85c.

After searching various suppliers I order some replacement parts from Farnell.

Closest spec in same package size was "Nichicon" branded, 3300mf, 25v, 105c - which seems like a good match. Replaced the two power caps mentioned above. I bought a few - would it be worthwhile replacing all the power caps at the front of the board?

For the audio caps, I ordered Panasonic 2200mf, 105c - but accidentally ordered 25v versions and not 16v as originally fitted. They are the same diameter and pitch size, so will fit - just twice as tall.

Is anybody familiar with the dacmagic to this level, or at least let me know if its "safe" to use 25v rated caps when 16v was used before? I intend to to replace the faulty audio cap and its partner on the other channel/circuit. Is it the capacitance or the voltage rating thats the important factor in the audio smoothing/final stage caps?

Sorry to waffle - I like to try and make myself clear. Thanks for reading and any help/advice appreciated!

Regards,

- Ian.

 

[testlab]

When it comes to capacitors, equal or higher voltage replacements are the rule. It sounds like you lost a main power supply filter and a couple of local bypass caps. They may have been under-rated or poorly manufactured.

 

[Fizzy]

Thanks for the reply.

I have now fitted/replaced the caps on the audio/final stages circuit as I mentioned and everything seems to be working ok again.

Keeping me eye out for any sign of smoke etc while I benchtest it, and ears open for any distortion/nasty noises on the audio output - but so far so good!

 

[sbrads]

The article at http://lickham.co.uk/pdfs/dacmagic.pdf may have helped, but it's nice to know you've got it working again. Electrolytics deteriorate especially if they've not been powered for a few years, perhaps the previous owner hadn't been using it.