| 1. time CDP - Modding, DCD-560 - Click HERE for Original Thread |
| Razorblade |
Hi all,
well after a long time of reading on this board its time for my first posting. I have a Denon DCD-560 and after reading this post :
http://www.diyaudio.com/forums/show...?threadid=74472
I thought... hey boy, why not went to the local electronics pharmacy, bought 2 NE5532P, ripped the RC4558P out and after 15 minutes of soldering the sound definately improved. So the next step will be exchanging the capacitors of the outputstage. I have no shematics of the player but there are 3 ceramic disk capacitors and 1 elco for each of the channels.
I am not sure on 2 things:
1. The correct capacitor values: ceramics are labeled : 682k = 68nF 10%, 102B = 1nF (But wth means the B ?), 201 = 200pF (200pf ??? thats definately not a standart value)
2. There is an 16v 10uF elco near the end of each Output stage and i have no clue at all what its doing there, 10uf is pretty big.
Can you help me confirming the right values for the capacitors, i want to exchange them all today to some MKP / FKP Wimas (widely availble here in germany) but 10uf ... damn i dont know if they have MKPs this large available in the store and they gonna cost hundreds of Euros ;) ... maybe Wima MKS but i dont know if thats any advantage over the elco, and maybe the elco has something to do with the power line of the opamps not the signal path ... decisions decisions, can you help me?
Thanks for your help
Razorblade |
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| pilli |
...no experts replied, so I'll try to give my two cents on the second question...
You'd have to check the exact position of the 10uF capacitor (I don't have a DCD-560 - you can just trace the tracks backwards from the output jack, it shouldn't be a long way), but it is likely that it is an "output coupling capacitor" that removes the DC from the output signal. That is a high-pass filter with a very low cutoff frequency (as much as possible below 20Hz).
10uF is not at all unusual. Of course a filter cutoff freq also depends on a resistance (which one...? here you see I'm not an expert... I can do the reasoning... but let's leave it as an exercise :clown: ), so sometimes you have output caps in the hundreds of uF.
If that capacitor is "bipolar" (marked with BP or NP or NonPol or something) then you can be pretty sure that it is a coupling cap.
Or if there are two electrolytics back-to-back.
But an elco by itself can also be.
MKPs definitely exist in those values. You can get decent quality ones for way under 10Euros. Try loudspeaker diy shops.
Hope this helps.
cheers,
gp
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| pilli |
...Denon's DCD-920 has a 100uF elco used as output coupling cap.
That's C318 and C319 in the attached schematic.
Your player should not be too much different.
(100uF non-electrolytics are out of reach, but I think you can try to replace it with 10uF, or several in parallel. That would raise the cutoff frequency by one order of magnitude. If it is from 2Hz to 20Hz, would it be audible? but phase is impacted too... up to you)
By the way, the schematic shows some 200pF too (eg C310).
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| Razorblade |
| Thanks for the tip with the DIY Loudspeaker store, they have 10uF MKPs, I will get one there and try it... it really seems to be the decoupling cap, but where to get 200p MKPs or FKPs ... :xeye: maybe the electronics pharmacy has some left, or ill take 2x100 in paralell. |
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| Razorblade |
| Modding is done, i exchanged all mentioned caps to MKP Types, but when I power it up and put a CD inside, it spins up as usual but displays 00 00:00:00 and it seems that it cant read no CDs at all anymore :bawling: Has anyone a solution where i can start looking for the failure? |
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| pilli |
...ooops, sorry to hear this.
It is quite strange that working on the output stage causes this.
Did you really only modify things "after" ("downstream") the DACs?
(edit: sorry to add this, just in case: the DACs are the chips marked "PCM61"...)
I would investigate first of all the following:
--> Forgotten/incorrect re-plugging of cables when you reassembled the different pieces (you may have disassembled the player to gain access to the board where you modded).
--> Something wrong done to power supplies. Some short circuit that prevents some supply to work properly (check with a voltmeter that you have the expected output from the regulators, most probably 78Xx / 79xx types). Or check at pins 8 and 4 of the opamps, respectively positive and negative supply.
Do you observe anything else worth mentioning?
Components unusually hot (transistors, ICs)?
ICs that are "unusually" cold? (the PCM61 and the opamps should warm up a little bit, if not they're not-powered/dead).
Not easy to do a remote troubleshooting...
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| Razorblade |
| It seems like a failed fuse because of a little solder blob between two components (shame on me), the slide servo isnt transporting the Laser anymore and on the -5v control point i get +0.74V ... so there must be something wrong and one of the "ic protectors" is non conducting, guess ill rip that out and replace it with a fast blowing fuse and see what happens next, i will keep you updated. |
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| Razorblade |
Thanks for your help Pilli,
everything is up and running again, it was a blown fuse and the CDP sounds quite nice know, I used intertechnik Q4 to replace the 10uf elcos and serveral other types of caps ( styroflex, and some ancient wimas ... i think they are mks) to replace the ceramic ones.
I will do some experimenting with the caps in the future since i am a "cap virgin" to see how they differ in sound, but i think the big MKPs will need some time to play in.
Has anyone got the schematics or the Service manual of the DCD-560 or does denon hand them out for free? Would be nice to have it if anything else breakes.
best regards
Razorblade |
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