CDJ 400 - not powering up

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dazzler22

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Joined 2012
#1
POWER PROBLEM SORTED - AUDIO PROBLEM NOW - SKIP TO POST 3!

Hi there.

So i have this pioneer cdj400. It was working ok apart from a few CD errors. Then it took a knock... (don't ask) and now it is not powering up properly.

I cannot see any physical damage on the pcb's, I'm guessing there is a broken solder joint somewhere. Anyone on here have experience with these units?
Could do with a point in the right direction to start testing.

Any help appreciated

Thanks!
 
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#3
OK manage to fix the powering up issue (was some dodgy soldering)

now I have another issue which is more this forums type of question. all th efeatures of the player are now working, all buttons led's and display,

the problem is that the audio output is very distorted and really quiet... (have to turn the gain right up just to hear it and it is mostly white noise with the muffled sound of the music in the background)

anyone got an idea on where to start testing?
(I have ordered an External DAC to see if this is an issue with the internal DAC)

the original problem was a soldering issue on the +5v as this is also used to power the DAC and DSP could this be a problem here?

Page 50 of the manual has the details for what i assume is the bit i need to test? where would you guys start?
as the sound is not only distorted but also really quiet could this suggest a power issue?

Service manual is here -> http://www.maetech.it/docs/datasheets/pioneer_cdj-400.pdf

any ideas greatly appreciated!

Thanks
 
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#7
Which is a good thing as repaing that board would not be fun!

I think that there might be a capacitor missing from the main pcb. I wonder if this is causing it. Will upload a pic later when I get home again.

Cheers
Daz

Sent from my HTC One X using Tapatalk
 
#8
ok the capacitor that is missing is a decoupling capacitor, could this effect the audio by making it quiet and muffled? it is on a different PCB to the DSP and DAC.

im guessing the problem now is a lack of power to the PCB with the DSP and DAC on it, at least i have a start, gonna have a propper test over the weekend when i get chance.

Cheers
Daz

Missing cap is here -> http://i279.photobucket.com/albums/kk145/dazzler222/missingcap.jpg

Main PCB Diagram -> http://i279.photobucket.com/albums/kk145/dazzler222/MainPCBUndersideCircuitsHighlighted.jpg
 
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#9
IM thinking maybe this should be in the analogue line level forum now!

so i have swapped parts with a known working unit and the problem is on the main pcb. it is difficult to test the voltages getting to the DSP board because of the way it all plugs together.

but the continuity all checks out to the point where it plugs in and i know the board is good already.

so the sound output is really distorted almost is if the gain is turned up too high but yet the output is really quiet. (I have to turn the gain right up on the mixer to hear the muffled distorted sound)

kind of at a loss as to what to test next now...

Any ideas??

Cheers
Daz
 
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