Pioneer CDJ-400 - No Display On Powerup

[dazzler22]

Hi Peeps,

Brand new member here looking for a little electronics help, I have a pioneer cdj 400 that i bought, it had a problem reading cd's but otherwise was working perfectly, I was about to replace the optical pickup (done this on a few players no big deal)

the trouble is when the cdj was on the way to me it took a knock in the post and now none of the lights or LCD are powering on.

my immediate guess would be a broken solder joint or grounding issue somewhere, i have removed the pcb and can find no obvious signs of damage to the board or any of the connecting components, so now the hard bit... need to start testing to find it.

This is where i need a little bit of assistance pointing in the right direction on where to start, I have experience soldering and have replaced surface mounted components before but always with guidance first.

I have found a service manual for this that includes the circuit diagrams and can provide pictures of the pcb.

can anyone help me?

Thanks
Daz

service manual - http://www.maetech.it/docs/datasheets/pioneer_cdj-400.pdf

 

[dazzler22]

I should add to this that when the unit is plugged into a pc via the usb port it is installed correctly and working, this leads me to believe that the issue is with the display and led circuit. as the rest of the unit appears to be working despite no display.

 

[dazzler22]

Also forgot to add these initial pics!

 

[dazzler22]

OK have a little more info now, when i plug this into the usb on my pc and link it to traktor every button and function is working, so it is deff something to do with what ever bit controls the lcd and led's can any budding circuit guru have a look at the schematic in the fist link and pint me in the right direction to test the LCD/LED section of the board?

also some better pics attached.

Cheers
Daz

 

[dazzler22]

ok a little more digging i found what looks like a lifted/burned trace?

see pic with circuit diagram (page 79 of the manual) am i correct in thinking this could be directly related?

sorry for the many replys!

 

[(*steve*)]

I have no idea if it's related, but it does look unusual.

Can you get a better image of this spot on the board? As it is, it is somewhat obscured and not very well in focus. (can you remove the board on top of it?)

Also, it is difficult to tell from the image from the manual what we're looking at, but we do have a long to the manual and the page number -- that helps enormously (it's in the lower right corner for anyone else having trouble finding it).

I think it would also be useful to take a look at the top side of the board in this location.

 

[dazzler22]

I took a couple before I left home (now away for the weekend)
Hopefully the will attach from here!

The soldering on this board suggests this has been repaired before or was a bad job from the factory.

 

[(*steve*)]

There's not really enough detail to make much out. The suspect spot now just looks like a component on the other side of the board with bare board between the traces.

There's an ugly scratch on the board and some places that appear to be darkened, but it might just be your lighting.

edit:

The suspect spot now just looks like a component on the other side of the board with bare board between the traces.

Scratch that, I was looking at a different part of the board. Yeah. It still looks funny. But not enough detail.

 

[dazzler22]

Ok when I get home I will take a couple pics with my dslr that should be a bit better than me phone!

Am I right in thinking the circuit VFD5R6P is the on that powers the LCD and led's? Or am I wrong on that one?

Must say this is fun learning as I go!

Thanks for the replys so far.

Cheers
Daz

 

[(*steve*)]

Page 76 shows a big chip in the top left corner that seems to control all the LEDs.

If none of the LEDs work, I'd be checking this has power.

I'd be asking myself "What is IC1100?" (And the answer seems to be PEG482A-K, but from there it's a dead end). It seems like it's a 5V powered chip, so check that power is getting to this board, and if so, is the voltage correct.

 

[dazzler22]

Ok that is a good point to test. When I get home I will see if power is getting there. of even if there is a link there.

Any other tips on testing? Or how I should test? I have been doing resistance tests to check a link is that correct?

Cheers
Daz

 

[dazzler22]

Oh and also there is some proper dodgy soldering on the board already. And a T has been written on the board in black marker, I'm guessing for test maybe?

 

[dazzler22]

ok finally back from the weekend away, will try to get these decent pictures up tonight. in the mean time at work i knocked up the attached pic from the split diagram i had, at least it gives me a point to test continuity!

I have highlighted in red the +5v circuit, ground is green,

if all the red is connected, then im guessing it could be a voltage problem.. or that controller is fried...

It worries me that a lot of the soldering for the +5v circuit looks like it has been redone and some of it is very messy, this suggest this has caused a problem before or maybe some of this messy soldering has broken causing the unit to have this issue... see on the attached pic near IC1100 every bit of bad soldering is on the +5v line.....

 

[dazzler22]

well it seems I have fixed it, under the light on close inspection there where a few of the dodgy looking solders that looked proper dodgy! so I removed the old solder and applied new.

unit is now powering up and seems to be working ok.

Thanks for the reply's you gave it is much appreciated!

next up is a broken motherboard and an amplifier.. but they will be separate threads once i dig them out of the loft!

Cheers
Daz

 

[(*steve*)]

Very well done.

The Mk:1 eyeball is often one of the best tools you have for faultfinding.

 

[dazzler22]

Soo close although all the buttons and display is now working the audio output is very quiet and distorted....

Any ideas?

 

[(*steve*)]

Identify the audio path through the amplifier and, working back from the output to the input, determine where the sound is no longer distorted. My guess is that the output stage is toast, but it may not be that.

You've got the service manual? take a look at the amplifier schematic and see if the output is a large integrated module or discrete electronics.

Given the previous problems were caused by bad soldering, look on the board for more examples of poor soldering. Maybe you'll have the same luck twice!

 

[dazzler22]

unfortunately it is discrete, there is no dodgy soldering on the board that does the audio side. (Pic Attached)

how would i test to see where the audio becomes distorted?

its at this point i almost need a guru of sound electronics... and im guessing some special test equipment...

 

[(*steve*)]

The sound might get distorted because a transistor (for example) is damaged.

The special equipment is a signal tracer. It's really just a small amplifier.

I'll take a look at your images when I get to a computer with a larger screen than my phone

 

[(*steve*)]

That doesn't look like an amplifier board. (I can tell that much from my phone)