Cambridge Audio d500 problem

seanzozo · 14th April 2009, 04:39 AM

My d500se was intermittent, so I opened it. it appeared that one of the caps in the main DAC PS had vented, so I replaced all four. Result, the player is still intermittent.

The power supplies appear stable. The digital out works fine. The output at times is at full voltage, operating normally, then it will distort badly or go silent. However when it is "silent" there is actually a very quiet signal that appears undistorted. It happens in both channels equally.

Looking at the board it appears that there are two separate data signals, one of the dac (5 pin) and one for the digital out (3 pin) which explains why the digital out works. The "silent" signal suggest to me that the data line for the DAC is good, the fact that both channels react equally sugests to me a PS problem, but the output of the regulators apears fine under no-load. Unfortunately I do not have a service manual. Any suggestions?

Edit-- it actually appears that one of the five NE5534 is not getting a negative rail on pin 4. The other 4 (2 per channel in the filter sections) NE5534 have +/- 5V rails but this one only has -5v on pin 7 and 0V on pin 4. I'm a little lost with digital, what does this 5th op-amp do?

Sean

seanzozo · 14th April 2009, 05:16 AM

The 5th opamp appears to have pin 4 grounded, so that's not the problem, still confused about that opamp.

jimmytwos · 14th April 2009, 09:54 PM

i had one of these that had a similar problem,
it would crackle and/or distort in one or both channel or sometimes go silent. it turned out to be the mute relay on the audio board, iirc it is either blk or white and marked musse? try giving it a firm tap and see if it clicks on or off (while playing music)
i eventually replaced the offending relay.

seanzozo · 14th April 2009, 10:01 PM

Thanks for the advice.

Last night I thought about the mute relay - I guess I can scope the output on the last opamp and check.

IIRC my relay is black and marked GOOD SKY - 9V

Sean

joshuajoshua · 21st December 2009, 04:46 AM

Quote:

Originally Posted by jimmytwos

.....i eventually replaced the offending relay.

Hi Jimmytwos,

Could you confirm that you fix the problem by replacing the relay?
I'm having the same problem with very faint followed by crackling distorted sound in my CA D500 series.

Thanks,

Joshua

14th April 2009, 04:39 AM	#1
seanzozo diyAudio Member Join Date: Jan 2005 Location: Austin	Cambridge Audio d500 problem My d500se was intermittent, so I opened it. it appeared that one of the caps in the main DAC PS had vented, so I replaced all four. Result, the player is still intermittent. The power supplies appear stable. The digital out works fine. The output at times is at full voltage, operating normally, then it will distort badly or go silent. However when it is "silent" there is actually a very quiet signal that appears undistorted. It happens in both channels equally. Looking at the board it appears that there are two separate data signals, one of the dac (5 pin) and one for the digital out (3 pin) which explains why the digital out works. The "silent" signal suggest to me that the data line for the DAC is good, the fact that both channels react equally sugests to me a PS problem, but the output of the regulators apears fine under no-load. Unfortunately I do not have a service manual. Any suggestions? Edit-- it actually appears that one of the five NE5534 is not getting a negative rail on pin 4. The other 4 (2 per channel in the filter sections) NE5534 have +/- 5V rails but this one only has -5v on pin 7 and 0V on pin 4. I'm a little lost with digital, what does this 5th op-amp do? Sean

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14th April 2009, 05:16 AM	#2
seanzozo diyAudio Member Join Date: Jan 2005 Location: Austin	The 5th opamp appears to have pin 4 grounded, so that's not the problem, still confused about that opamp.

14th April 2009, 09:54 PM	#3
jimmytwos diyAudio Member Join Date: May 2007	i had one of these that had a similar problem, it would crackle and/or distort in one or both channel or sometimes go silent. it turned out to be the mute relay on the audio board, iirc it is either blk or white and marked musse? try giving it a firm tap and see if it clicks on or off (while playing music) i eventually replaced the offending relay.

14th April 2009, 10:01 PM	#4
seanzozo diyAudio Member Join Date: Jan 2005 Location: Austin	Thanks for the advice. Last night I thought about the mute relay - I guess I can scope the output on the last opamp and check. IIRC my relay is black and marked GOOD SKY - 9V Sean

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