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Cambridge Audio 851c - problems and possibe repair?
Cambridge Audio 851c - problems and possibe repair?
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Old 9th June 2019, 12:41 PM   #1
lundbeck is offline lundbeck
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Default Cambridge Audio 851c - problems and possibe repair?

Hello,


I own a Cambridge Audio 851c CD-player/DAC/Pre-amp which I am currenty using av a DAC/Pre-amp.


Lately it has started acting up: WHen powering it on it will produce loud, static white noise. Usually switching it off and on a couple of times removes this problem, and it works as expected after this. However, as this i quite annoying, I decided to open it and have a look inside as the unit is out of warranty.


I inspected the insides and found what appears to be bad capacitors on the power board, which again is connected to the toroidal transformer. The DAC/pre-section looked fine.



I've attached some pictures of the power-board.



Could this be the cause of the problem described?
Could swapping the capacitors be a simple repair?
If so, does Cambridge Audio use "standard" soldering lead, or is there something which I should be aware of?


The values of the caps that seem bad are as follows:
C3 - 15 uF 450V, labeled 1921TQ
C14 - 1500uF 16V, labeled 92GW
C2 - 1000uF 16V, 10IICH


If this might be a matter of simply swapping the caps are there any recommended brands/types of caps or will any do?


I appreciate all and any input, thank you.
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Old 9th June 2019, 07:29 PM   #2
Mooly is offline Mooly  United Kingdom
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Cambridge Audio 851c - problems and possibe repair?
That could be some kind of glue you are seeing and used to add mechanical support to the tall caps... its often seen in commercial gear.

I assume you mean the noise in on the audio feed and not actual physical noise from the SMPS... if so then you may be looking at a different issue.

Recapping is an easy job on something like that, and often its the small caps that give problems just as often as the large. Always change ALL electrolytics. Look for parts rated at 105C and always check physical sizes before ordering. Go for big brand names such as Panasonic or Rubycon.

Use normal solder would be my advice, no matter what was used in production.
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