HELP!. Need SM for DCD-2560 cdp. fast spin after mods

[homemade]

Please help me out if you can. My much admired Deno DCD-2560 cdp no longer reads disc's after modifing This player uses 4 AD1862 DAC's for conversion , so I would REALLY like to get this thing working properly. The mods I preformed were mostlyt o the output stage , and only included new p/s caps , new op amps(AD826 , 10 of them) ,some bypassing , poly output caps and the like.. The only thing besides these mods was a clock module(Burson pre made). I was careful through out the process. When I power it up , the disc will spin at full speed and then eject , while continuing to spin. The optical sled also SLAPs from center to full travel. I get 12v readings at the SERVO op-amps output pins.(BA15218). I tried changing clock connections and even replaced the old one , but still the same. MAYBE ESD?? The main decoder chip is the Sony CXD2500 , which seems to do most everything(data sheet). If someone familiar with this or other Denon cdp's can lend a hand , it would make someone very happy(ME).Thanks, Paul

[Ruach]

I think that this has to do with the clocking.

Change the clocking back to the original state and see if the problem persist.

If you have a scope, check if the Burson clock gives the correct signal waveform.

[homemade]

Originally posted by Ruach
I think that this has to do with the clocking.

Change the clocking back to the original state and see if the problem persist.

If you have a scope, check if the Burson clock gives the correct signal waveform.

Ruach

Thank-you for the reply. I have re-installed the original clock(crystal) and the same problem still remains. Everything was fine before modding. I DID NOT have any grouding on myself or the circuit board at the time , so I have to believe ESD is the culprit. I'm just hoping somenone familiar with DENON players would know which chip is most to be effected. Anyone know a good place to get a service manual?

[Ruach]

You may have damaged the Sony CXD2500. Did you put a 1K resistor in series with the clock output connection of the clock before you power it up?

I suspect that the clock may not have been fully tested or probably installed.

The only time I see such a symptom that you described was when there was a clock failure which affected the servo.

How about the servo chip? Is it working fine?

[rejithcv]

I suspect the optical eye in such cases. If the drive tends to rotate the CD, then the digital circuits seem to be ok. Else this won't happen (no spinning, laser emission). You also have to check whether the laser light is emitted or the laser diode can be blamed for that. If incase, accidently the lens was in contact with any objects, there is a chance to make a bad allignment. All of them will show similar behaviour. This is the most common problem in all CD drives with replacement the only solution. A change in crysal, in any of the circuit will do make the whole system to standstill.

[pilli]

I know that this was more than six months ago, but just in case somebody falls around here while searching, I happen to have just fixed a Denon DCD-1650GR that was showing similar symptoms
(if I get it right, this is pretty much a Japanese version of the 2560, anyway quite similar inside.)

The problem in my case was that two transistors driving the mechanism were burnt. It was the two transistors opening the tray, but for some reason they caused the spindle motor to rotate like crazy. (The tray is controlled directly from the cpu chip, through a BA15218 then these complementary driver transistors.)

Last year I had a similar symptom on a Cambridge CD4 (if I remeber right it's a Sanyo mech with Sony controllers) and this time it was one power rail that was off.

Just to say that in both cases I was afraid that something would be wrong in some of the Sony CXx chips, given the symptom. Instead it was somethign simpler, yuppie.




_

[homemade]

Just a quick update on this player. I found the SM online. Best $15 I spent on this project. It seems that after I added MUCH local capacitance , the IC PROTECTORS could not handle the load. Thing is that only one side blew(+v). Made the transport section do weird things(back spin , open close). Thought I burnt one of the big chips. I also melted the laser lens(??). Bought a new laser assembly from MCM. I installed that with little trouble , along with new IC protectors. Got good voltage readings throughout. But still no read or dsc spin. I searched the site and after a few weeks found out about the solder short on the laser cable. Removed that , pressed play , and all was good.
As for additional mods , went with the data sheet for the AD1862 dac .Decoupled EACH p/s pin , along with added series inductance. Did the same for all the DSP chips . Used the mentioned AD797 , along with the embedded reference feedback resistor in the 1862 , for I/V. Did all the recc. bypassing/decoupling. Replaced the stock summing and LPF opamps with AD826's. Currently using BURSON's HDAM Buffer modules with their precision p/s . The p/s is highly biased class A and gets VERY hot , even with big heatsinks. The modules run on 25vdc and are DC coupled(no output caps). I'm still working on trying to keep the p/s cool enough for me to not be afraid of leaving it alone , but this is the best output stage "I" have listened to in a cdp , and beats any op amp to date(AD826, LM6172 ,OPA2132 ,OPA2604 ,etc). I'm certain there are those who are much more capable at making digital sound good , but own 20+ players(JVC-1050 , PD-8500 , 707ESD, Philips CD-80 , Revox 226, +++) all with some tweaking , but this DENON gives me musical enjoyment.

[Javin5]

I also have a DCD-2560 and would like to know if its worth modding. A lot of progress has been made since this unit was designed, newer IC's etc. Would this be a limitation to the obtainable sonic improvements?

I'm also a little skeptical about the rather large number of opamps and the variable pitch control and its influence on jitter. But I may be wrong.

Unfortunately, the CD-drawer doesn't close all the way any more; I have to manually push it in for the last 3 mm. This is something I would like to fix before starting with any mods. Did anybody else have this problem? Any hint how to fix this?

I don't want to intrude on this thread with these questions, but hope that I may possibly find some advice here from other Denon DCD-2560 owners.