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-   -   NAD C525BEE - "No Disc" Trouble Shooting Advice wanted (http://www.diyaudio.com/forums/digital-source/188386-nad-c525bee-no-disc-trouble-shooting-advice-wanted.html)

tiefbassuebertr 4th May 2011 07:07 AM

NAD C525BEE - "No Disc" Trouble Shooting Advice wanted
 
This compact disc player from NAD uses the SONY mechanism KSM213CCM with laser pickup KSS-213C. The compact disc turns on, two times in CD/CDR mode and two times in CD/RW mode. RF signal is normal while the "read-in" try. But TOC wasn't detected.
A new mechanism doesn't change the situation and the old mechanism so as the old flex connector from C525BEE works fine in an other compact disc player device.
BTW - the model C525BEE haven't no longer agjustment devices for tracking and focus gain/offset. Soldering is already PBfree (lead free).
What failure is most likely on the PCB? Perhaps certainly electrolytics?

Mooly 4th May 2011 07:27 AM

PLL adjustment maybe ?

singa 4th May 2011 08:09 AM

Hi, Did you remove the anti static short at the laser module?
Did the laser turn on and the spindle spin when trying to read?
Did the laser go to home position near the inner part or starting
part of cd?

It is possible the laser forcusing IC is bad or the laser driver IC
too.You need the service manual for this.Could also be a bad spindle
motor ,the resistance should be about 12 ohms. Good luck.Also check
for solder joint breaks.

tiefbassuebertr 4th May 2011 08:48 AM

Quote:

Originally Posted by Mooly (Post 2560910)
PLL adjustment maybe ?

No. Adjustment present only for APC (laser unit, on board) and display illumination brightness (R709, main PCB - btw: the brighter, the louder the unwanted mechanical sine wave pip from display).

Follow chips are in use:
U201: BA6392FP, 4-channel BTL driver for CD players (Rohm)
BA6392FP Datasheet pdf - Optical Disc LSIs > Motor/Actuator driver > CD/CD-ROM driver(4ch) - ROHM
U301: CXD3017, CD Digital Signal Processor with Built-in Digital Servo and DAC (Sony)
http://www.datasheetcatalog.org/data...y/e6801333.pdf
U302: PCM1710U, DAC
U101: 620P57 Photo diode signal processor (for me unknown type - could be also other because very hard to read from chip surface)
U401: operating MCU in QFP outline without type number, firmware version according sticker on it: c521/525 05262006
If there are breaks or GND short in the connections for data exchange between U301 and U401 (PCB wires or internal bonding of both chips itself, P1-P9 page 116 datasheet CXD3017Q), the fixing of exactly error reason is probably hard to realize.

Quote:

Originally Posted by singa (Post 2560937)
Hi, Did you remove the anti static short at the laser module?
Did the laser turn on and the spindle spin when trying to read?
Did the laser go to home position near the inner part or starting
part of cd?

Yes for all.
Quote:

Originally Posted by singa (Post 2560937)
It is possible the laser forcusing IC is bad or the laser driver IC
too.Could also be a bad spindle
motor ,the resistance should be about 12 ohms.

unlikely; mechanism include spindle motor works fine by other cd player model
Quote:

Originally Posted by singa (Post 2560937)
Hi, You need the service manual for this.

Yes, but not from NAD (not well troubleshooting descriptions) but from a Sony cd player model, where the same CXD3017Q PCM decoder is in use. Who knows such a model?
BTW - The NAD C521BEE could be use the same topology in that aera, from where comes that error - go to
http://noresin.com/files/NAD%20C521BEE.pdf
U101 here is CXA2581
http://www.datasheetcatalog.org/data.../199475_DS.pdf
and U401 follow: Mitsubishi M38223 E4HP4
http://www.datasheetcatalog.org/data.../1022028_1.pdf
http://www.datasheetcatalog.com/data...M38223M4.shtml

tiefbassuebertr 4th May 2011 09:44 AM

Differences between NAD 521 and 525
 
NAD C 525 BEE - audio - Magnus.de
http://www.superfi.co.uk/index.cfm/p...roduct_ID/3090
http://audiojunkies.com/forum/cd-pla...-c525-bee.html
http://hifigoteborg.se/nad_manuals_self/C521BEE.pdf (complete manual)

Mooly 4th May 2011 11:08 AM

Hard to say. Does the pickup return to its rest position if you manually move it outward and then power up?

You say the RF is OK ? Does the disc appear to run at correct speed while trying to read TOC.

Are all supplies correct and clean as measured at their destintions ?
Is the tracking coil drive to the pickup working OK ?

You now the mech is OK. If the RF is good and reaching its destination cleanly then it does sound like the servos/data processor are not synced. Spillage ?

tiefbassuebertr 4th May 2011 04:50 PM

Quote:

Originally Posted by Mooly (Post 2561041)
Hard to say. Does the pickup return to its rest position if you manually move it outward and then power up?

You say the RF is OK ? Does the disc appear to run at correct speed while trying to read TOC.

Are all supplies correct and clean as measured at their destintions ?
Is the tracking coil drive to the pickup working OK ?

You now the mech is OK. If the RF is good and reaching its destination cleanly then it does sound like the servos/data processor are not synced. Spillage ?

The last is most likely the case. Also the not correct tracking coil drive could be the reason, but if I cut the Tracking signal-PCB wire, the behaviour is other (disc speed goes higher and higher).
About
Videohifi Forum
I note, that Sony's last generation cd player (XE-series) uses not the last generation decoder chips - in use is the CXD2545Q and CXD2585Q.
In the Sony car hifi changer model CDX-602/21 and CDX-602/17 the CXD3017Q is in use (together with LA6576L, LB1930M and BA8272), as to read about
http://lamson.dnsdojo.com/DATALIST/A-Z-PDF/06079.txt
but this model uses also the CXD3017
http://elbase.ru/app/webroot/files/t...X1/HCDCPX1.pdf

Mooly 4th May 2011 05:02 PM

I can't think of anything else to try... maybe it is spillage. If the disc speed increases with the tracking disconnected it sounds like that part is working OK.

The old engineers trick (well one of mine :)) of using damp fingers to try and "pull" any oscillator etc ... just to see if you can get it to lock comes to mind.

Dunno... would need it hooked up on the bench to investigate further.

guytou 4th May 2011 08:50 PM

do you have a push-pull of transistors on focus/tracking ? A repetitive default on these players was bad solder on these transistors or weak/dead transistors . The plant was aware of this default , they print a note about this

tiefbassuebertr 4th May 2011 10:36 PM

Quote:

Originally Posted by guytou (Post 2561687)
do you have a push-pull of transistors on focus/tracking ? A repetitive default on these players was bad solder on these transistors or weak/dead transistors . The plant was aware of this default , they print a note about this

Indeed - that was the first error of this compact disc player: Not present lens driving for goes up and down and therefore no FOK signal and no turn on the disc. After resolder this transistors the above descripted is to observe
Quote:

Originally Posted by Mooly (Post 2561366)
The old engineers trick (well one of mine :)) of using damp fingers to try and "pull" any oscillator etc ... just to see if you can get it to lock comes to mind.

Such things sometime CD devices may bring back to life - unfortunately not in this case. My estimate is the MCU U401 itself or shortings arround this; I note extremly bad leadfree solder work arround this 80pin LQFP-MCU (12✕12mm plastic body).
P.S.
I don't understand this term:
.........maybe it is spillage


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