Hi guys!
My mixer has started to act up. If I plug a cd player (or any line level sound source) in to the mixer it produces sound with no distortion (albeit at a very quiet level ?) This is on both the analog inputs and digital. But... If I connect my turntables on the Phono input.... The distortion is unbelievable, with every bass drum kick of a song it just crackles or makes some high pitched noise. Also not sure if this is related to the issue but the master will not go above -7 on the meter in general. The channel faders will go to max and hit the red, when hitting the red the master will then actually hit -1 or Zero but no more and there is no way of me getting it any louder....

I hope I've made sense haha. I have tools to test components. I would say I was a novice, so I may need things explaining a bit more, so just bear with me please. I have downloaded the service manual as well (just in case anybody was going to ask).
Thank you in advance guys.
Jace

 

You'd better stick the manual in here or we'll just be guessing.

 

The manual is 20MB+ so the site won't let me upload it. So here is a link...

https://www.manualslib.com/manual/695548/Pioneer-Djm-800.html

Cheers.

 

Page 71 of the manual shows the main power supply outputs and this is the place to start. Check all the outputs shown here.

Following this page is a list of control/input conditions for measuring voltages and then on the following pages are tables of voltages at many points in the circuit and I expect we will be referring to these later.

 

Page 12 of the manual has the block diagram of the input functions, you can narrow it down by inputting the signal into each section to see where the fault lies. Then goto that circuit using the manual to check for voltages and signal levels.

 

Noticed this on the DSP board.... I guessing that's not good?

 

It looks like a not very professional repair but if it was working previously with that in there then it isn't the cause of the problrm.

 

Page 12 of the manual has the block diagram of the input functions, you can narrow it down by inputting the signal into each section to see where the fault lies. Then goto that circuit using the manual to check for voltages and signal levels.

Hi Dave, this fault happens across all channels with a phono input, when I flick it over to 'Line' it stops..

 

Hello,

The link on your picture should be a capacitor, according to this drawing from the manual:



When there is a link in place of a capacitor, the DC voltage will be influenced.

Bertus

 

Hello,

The link on your picture should be a capacitor, according to this drawing from the manual:

View attachment 152807

When there is a link in place of a capacitor, the DC voltage will be influenced.

Bertus

Aha, So before going any further replace this link then. I've never seen the mixer working correctly you see it came to me like this. Cheers

 

It looks like a not very professional repair but if it was working previously with that in there then it isn't the cause of the problrm.

I've never actually seen the mixer working correctly Albert, it came to me like this. Apologies I didn't state this before. With it being on the DSP board would that not directly have some effect on the sound?

 

Hi Dave, this fault happens across all channels with a phono input, when I flick it over to 'Line' it stops..

Which channel is it faulty on the phono input but ok on the line?

 

Channels 2, 3, and 4. (Channel 1 is only Line/Digital). To me (I could be extremely wrong here, as I don't know enough about this stuff) It's like there is a phono pre amp that is active on those three channels or whatever supply's them and that is blown, as I find it very hard to believe that all three channels have exactly the same blown component. I hope I make sense here haha. Cheers