CAMBRIDGE AZUR 840C: Dodgy Chinese capacitors.
Hi Folks,
I'm new to this forum, but would like to seek your advice.
I have a Cambridge AZUR 840CD Player. Nice one , IF it works .
It already had an intermittent problem with the CD (Sanyo) drive, (a couple of years ago), which I repaired by exchanging it for a new one (they are quite cheap ; about 40$.
Now, the player has developed another problem, which seems to be common for this type..
Once switched ON from cold, initially both channels pop & crackle.
One (L) quickly recovers though, and is fine after some 5 minutes.
The other (R) channel stops with popping and crackling, and does not recover but has much reduced output (50% less), some distortion/white noise.
Some 2 months ago, also this channel would recover, but it has deteriorated over time.
The rest of the player is AllRight. Currently I feed the digital output signal into an external DAC (part of TASCAM HS2) and still can enjoy the music.
I heard from the Importer's Service Rep (nice chap) that there are bad capacitors in the DA system / power supplies.
Looking at the schematic, I would like to replace C152, C156, C159, C98 (10 uF NP), left channel and C54, C154, C55, C99 (10uF, NP) Right channel, all around the DA chips.
I read somewhere that the service dpt . of Cambridge replaces some cap's as a matter of course (each time an 840C is brought in).
Are these indeed the offending C's ??
Furthermore, I intend to replace C64/C65 (10u, 35V) DAC1_VA_+5V
C112/C250 (10u, 35V) DAC2_Va_+5V
C46/C137 (100u 35V) +/_ 15V LCH
C104/C105 ditto RCH
C115 10u 35V +5V DAC
C247 10u 35V -5V
C246 ditto -5V(2)
C141 ditto +5V
These are all major C's in the DA converter + OpAmps I can think off.
I do not want to MOD the player ; just fix it
Any more suggestions??
Which Caps should I use?? I intend to at least double the Working Voltage of the CAPS (to 63V) and use Panasonic caps (freely available from CONRAD)..
Will this do the trick in your opinion??
NB I have included the schematic.
http://akdatabase.org/AKview/albums/...0840C%20SM.pdf
Any help is welcome!
Thanks for your support!!
kind regards,
Martin , Holland
Hi Folks,
I'm new to this forum, but would like to seek your advice.
I have a Cambridge AZUR 840CD Player. Nice one , IF it works .
It already had an intermittent problem with the CD (Sanyo) drive, (a couple of years ago), which I repaired by exchanging it for a new one (they are quite cheap ; about 40$.
Now, the player has developed another problem, which seems to be common for this type..
Once switched ON from cold, initially both channels pop & crackle.
One (L) quickly recovers though, and is fine after some 5 minutes.
The other (R) channel stops with popping and crackling, and does not recover but has much reduced output (50% less), some distortion/white noise.
Some 2 months ago, also this channel would recover, but it has deteriorated over time.
The rest of the player is AllRight. Currently I feed the digital output signal into an external DAC (part of TASCAM HS2) and still can enjoy the music.
I heard from the Importer's Service Rep (nice chap) that there are bad capacitors in the DA system / power supplies.
Looking at the schematic, I would like to replace C152, C156, C159, C98 (10 uF NP), left channel and C54, C154, C55, C99 (10uF, NP) Right channel, all around the DA chips.
I read somewhere that the service dpt . of Cambridge replaces some cap's as a matter of course (each time an 840C is brought in).
Are these indeed the offending C's ??
Furthermore, I intend to replace C64/C65 (10u, 35V) DAC1_VA_+5V
C112/C250 (10u, 35V) DAC2_Va_+5V
C46/C137 (100u 35V) +/_ 15V LCH
C104/C105 ditto RCH
C115 10u 35V +5V DAC
C247 10u 35V -5V
C246 ditto -5V(2)
C141 ditto +5V
These are all major C's in the DA converter + OpAmps I can think off.
I do not want to MOD the player ; just fix it
Any more suggestions??
Which Caps should I use?? I intend to at least double the Working Voltage of the CAPS (to 63V) and use Panasonic caps (freely available from CONRAD)..
Will this do the trick in your opinion??
NB I have included the schematic.
http://akdatabase.org/AKview/albums/...0840C%20SM.pdf
Any help is welcome!
Thanks for your support!!
kind regards,
Martin , Holland
The caps you are planning to replace are all of quite high nominal voltage ratings and are unlikely to be cause of the problem. The non-polar types are probably used because of lower distortions and/or specific sound characteristics.
I'd start at the power supply section; in particular around TIP31 transistors that regulate the voltages for logic sections and DAC's... The circuit diagram specifies the current draws, so if you are handy with the multimeter, you could narrow down the problem fairly quickly.
Good luck,
Boky
I'd start at the power supply section; in particular around TIP31 transistors that regulate the voltages for logic sections and DAC's... The circuit diagram specifies the current draws, so if you are handy with the multimeter, you could narrow down the problem fairly quickly.
Good luck,
Boky
Agree with this. Martin, before you spend any efforts in replacing all these caps,
I'd first check voltages and cords from transformer to PCB and CD drive to PCB.
I'd first check voltages and cords from transformer to PCB and CD drive to PCB.
In addition, and if you just want to fix it i'd replace any capacitor with some quality ones of same value and voltage. Do no alter them in any way or the results might not be as expected.
Hi All,
Thanks for the replies.
I do not fully agree with all of your answers, though, for the following reasons:
1) The circuits (downstream of the TIP -31 's Q10, Q11) all work fine (Servo, DSP ); After all the player works OK in the digital domain, and feeds digital signal outs (which can be processed by an external DAC). As such the player plays fine. Only the DAC circuits fail (or their power supplies)..
Certainly there are no loose wires,otherwise entire sections of the player would fail (including servo, dsp) which does not happen.
2) Additional info (without taking any instrument, yet ) is the info (internet, importers repair lab) that this player has some Chinese capacitors which break down systematically.
(apparently they were copies of a Japanese design) but the copy went wrong!
2-14-10: Nishna
Sent my 840C in for repair, Dec 2009. I asked Audio Plus Serv. rep (North America) if the 840C had any design upgrades since my model was manufactured. He said they use better capacitors in the power supply now, which my player did not have. He said everything else has stayed the same since the player was first introduced. He said they install these power supply caps on any 840Cs returned for repair, normal practice. So evidently I have these new capacitors now installed. Sounds great.
See also :
Aaaggh - sick Cambridge Audio CA840C CD player
http://www.diyaudio.com/forums/digital-source/227531-cambridge-840c-problem.html
They talk about replacing 10u 35V Caps, most likely these are the 8 NP 10 uF Capacitors NP around the DAC,s wich are also upgraded by some firms:
vicol audio : cambridge audio azur 840c audio tuning
But I agree with you : Measure the voltages first ("meten = weten").
BTW
The reason for replacing the other cap's : If one is faulty, there will follow more.
Agree with you that this might not be necessary at all (maybe they are even another brand, with no quality problems.
Regards,
Martin B.
Thanks for the replies.
I do not fully agree with all of your answers, though, for the following reasons:
1) The circuits (downstream of the TIP -31 's Q10, Q11) all work fine (Servo, DSP ); After all the player works OK in the digital domain, and feeds digital signal outs (which can be processed by an external DAC). As such the player plays fine. Only the DAC circuits fail (or their power supplies)..
Certainly there are no loose wires,otherwise entire sections of the player would fail (including servo, dsp) which does not happen.
2) Additional info (without taking any instrument, yet ) is the info (internet, importers repair lab) that this player has some Chinese capacitors which break down systematically.
(apparently they were copies of a Japanese design) but the copy went wrong!
2-14-10: Nishna
Sent my 840C in for repair, Dec 2009. I asked Audio Plus Serv. rep (North America) if the 840C had any design upgrades since my model was manufactured. He said they use better capacitors in the power supply now, which my player did not have. He said everything else has stayed the same since the player was first introduced. He said they install these power supply caps on any 840Cs returned for repair, normal practice. So evidently I have these new capacitors now installed. Sounds great.
See also :
Aaaggh - sick Cambridge Audio CA840C CD player
http://www.diyaudio.com/forums/digital-source/227531-cambridge-840c-problem.html
They talk about replacing 10u 35V Caps, most likely these are the 8 NP 10 uF Capacitors NP around the DAC,s wich are also upgraded by some firms:
vicol audio : cambridge audio azur 840c audio tuning
But I agree with you : Measure the voltages first ("meten = weten").
BTW
The reason for replacing the other cap's : If one is faulty, there will follow more.
Agree with you that this might not be necessary at all (maybe they are even another brand, with no quality problems.
Regards,
Martin B.
Best approach for electro's is to measure their ESR. There are some quite affordable hand held multimeters with ESR functionality. Buy or borrow one and measure them. If at all suspicious replace them with the highest quality ones you can buy. You can usually measure ESR in circuit with these meters. After many years of repairing electronic equipment both domestic and professional I have learned to suspect electrolytic caps, particularly low value ones and especially switch mode power supply filter caps. Quite often they give them selves away by having bulging tops. Heat is the enemy here. They probably account for 80% of faults in my experience. Even high quality ones are not very expensive so if in doubt replace. I am interested in the outcome as I have recently purchased a Cambridge Audio Stream Magic 6 and I am extremely happy with it so far. It absolutely kills my CD player for detail and dynamics.
Last edited:
I bought one of these for testing capacitors
It's only a cheap thing, but seems accurate enough for what I need
TRANSISTOR TESTER NPN PNP MOSFET THYRISTOR DIODE RESISTOR CAPACITOR METER dc 9v | eBay
It's only a cheap thing, but seems accurate enough for what I need
TRANSISTOR TESTER NPN PNP MOSFET THYRISTOR DIODE RESISTOR CAPACITOR METER dc 9v | eBay
Hi Martin,
the way to troubleshot this problem is quite simple and fast.
you are going to need hair dryer and freezer spray Electrolube Freezer Spray distributed by HK Wentworth
1- open the cover
2- heat up the suspicious areas and you will hear the fault going away.
3- with the freezer spray , freeze the suspicious components till the fault re-occurs then you will know 110% what components is faulty
Note: 80% of cold to hot faults in any electronics devise are cause by capacitors, the other 19% by a semiconductor and 1% by others factors
Regards
Alex
the way to troubleshot this problem is quite simple and fast.
you are going to need hair dryer and freezer spray Electrolube Freezer Spray distributed by HK Wentworth
1- open the cover
2- heat up the suspicious areas and you will hear the fault going away.
3- with the freezer spray , freeze the suspicious components till the fault re-occurs then you will know 110% what components is faulty
Note: 80% of cold to hot faults in any electronics devise are cause by capacitors, the other 19% by a semiconductor and 1% by others factors
Regards
Alex
I tried the link with no success. The meter needs to be able to measure ESR not just Capacitance. The great thing about ESR meters is their ability to test most caps in circuit. They place a high frequency signal at low level across the cap to be tested and determine it's ESR from it's impedance at that frequency. You have a look up table for the cap value to determine if the ESR reading is good or bad for that particular value. A high ESR reading means faulty cap. It's one of my most used bits of test gear these days. Especially useful for Chinese switch mode supplies which always use low quality caps. I have found that component layout can be a problem also with Electros placed next to high wattage resistors etc. When replacing them I separate the components as best I can. A faulty cap often has a bulging top and the plastic label cover shrunk back and discolored.
Many thanks for the suggestions!
Hi all,
Many thanks (all of you) for your support!
I will try the heat (and cold) treatment on the suspect NP capacitors and all polar Electrolytic Cap's in the power supplies of the DAC and OpAmp stages and see what happens...
BTW.
I see that the 8 (suspect) NP 10 uF 35V capacitors (Brand R&C) have been replaced by NP 10 uF 35V capacitors of the brand Fujicon (FUJI ?) on the recent boards.
Maybe these are indeed the faulty Caps which the US Importer/Service shop replaces in this 840C player, as a matter of course, according to the internet fora, e.g.
Aaaggh - sick Cambridge Audio CA840C CD player
All other C's are the same brand still and are identical to the ones on the old board.
Are ther any kown quality problems with the brand R&C? I was told by a colleague that a certain Chinese Capacitor manufacturer had a quality problem : This resulted in premature breakdowns in lots of equipment.
Cheers!
Martin
Hi all,
Many thanks (all of you) for your support!
I will try the heat (and cold) treatment on the suspect NP capacitors and all polar Electrolytic Cap's in the power supplies of the DAC and OpAmp stages and see what happens...
BTW.
I see that the 8 (suspect) NP 10 uF 35V capacitors (Brand R&C) have been replaced by NP 10 uF 35V capacitors of the brand Fujicon (FUJI ?) on the recent boards.
Maybe these are indeed the faulty Caps which the US Importer/Service shop replaces in this 840C player, as a matter of course, according to the internet fora, e.g.
Aaaggh - sick Cambridge Audio CA840C CD player
All other C's are the same brand still and are identical to the ones on the old board.
Are ther any kown quality problems with the brand R&C? I was told by a colleague that a certain Chinese Capacitor manufacturer had a quality problem : This resulted in premature breakdowns in lots of equipment.
Cheers!
Martin
cambridge 840c faulty caps
hi guzz1 my player had a distorted right channel for about 20 seconds at switch on see my other post i have added a pic of the cap i found to be faulty its cap c217 a 10uf 35v found it with freeze spray method there are (27 x10uf 35v ) (10 x10uf 16v) and (8x 10uf 50v non polarised) caps around the dacs and regs .
i am thinking about changing them to elna cerafines 37 x 10uf 50v and 8 x 10uf 50v np caps would this be a good upgrade or a waste of cash and time as this cdp has no caps in signal path
regards Glenn
hi guzz1 my player had a distorted right channel for about 20 seconds at switch on see my other post i have added a pic of the cap i found to be faulty its cap c217 a 10uf 35v found it with freeze spray method there are (27 x10uf 35v ) (10 x10uf 16v) and (8x 10uf 50v non polarised) caps around the dacs and regs .
i am thinking about changing them to elna cerafines 37 x 10uf 50v and 8 x 10uf 50v np caps would this be a good upgrade or a waste of cash and time as this cdp has no caps in signal path
regards Glenn
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cool, elna cerafine caps are really good, but those caps are just in the v+ regulator cct, anything will do, but I would recommend change them all in that section maybe will only cost you $20 bucks in elna caps
Hi
Thanks for the support.
All 10uF, 50V elco's were changed (by Rubicon) and player is fine again.
Was this due to inherently bad Capacitors (or because the C's are too close to the hot heatsink and get roasted?).
In the latter case , the lay out of the PCB is inherently wrong.
Regards,
Martin
Thanks for the support.
All 10uF, 50V elco's were changed (by Rubicon) and player is fine again.
Was this due to inherently bad Capacitors (or because the C's are too close to the hot heatsink and get roasted?).
In the latter case , the lay out of the PCB is inherently wrong.
Regards,
Martin
looks like a dodgy batch of caps 😡 anyway i have orderd a full set of elna cerafines to replace all the caps apart from the 10 power supply caps which all tested ok and the 8 10uf N/P caps will be replaced with Nichicon ES i have also got some dynamat to dampen the case. anyone got any advice on what to dampen on the cd drive ? also i have just realised the cerafine are 85 not 105 temp caps will this be a problem for the caps near the regs ?
regards Glenn
regards Glenn
Hello all,
I just finished repairing one AZUR 840C. It happened that the right channel is noisy, distorted, and lower amplitude.
I found the 10Vdc for the right channel DAC reads only 2.8V and the output of the 2.8V regulator reads only 2.65V. I checked the ESR of C217 is 6.5 ohm which may possible cause the 10V regulator U42. I had the capacitor and U42 replaced with new spare. I check other capacitors on the board and found many of them are having high ESR. I had them replaced as well.
After these works, the unit works fine and singing sweetly.
Johnny
I just finished repairing one AZUR 840C. It happened that the right channel is noisy, distorted, and lower amplitude.
I found the 10Vdc for the right channel DAC reads only 2.8V and the output of the 2.8V regulator reads only 2.65V. I checked the ESR of C217 is 6.5 ohm which may possible cause the 10V regulator U42. I had the capacitor and U42 replaced with new spare. I check other capacitors on the board and found many of them are having high ESR. I had them replaced as well.
After these works, the unit works fine and singing sweetly.
Johnny
Cause of the problem:-
There is no ventilation within the chassis. The heat from those linear regulators are very high. I measured the temperature at the heat sink was 40 deg C while the room temperature was 20 deg C. With the top cover on, the temperature will probably get up higher to 50 deg or more.
There is no ventilation within the chassis. The heat from those linear regulators are very high. I measured the temperature at the heat sink was 40 deg C while the room temperature was 20 deg C. With the top cover on, the temperature will probably get up higher to 50 deg or more.
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