[morast]

Hi,

i finished my 2nd MP573 build and I'm having troubles getting it to work & would need some advice / guidance.


When the DI board is inserted, JMP3 removed, everything works fine. However, with no DI board, JMP3 on + Mic/Signal via XLR, there is no output.

Tests / measurements I did so far:

DC Values A-K all have the correct voltage.

AC Values with multimeter on 50hz Sine wave via XLR Input:
* In+ to In- : 0,6V
* C2 to C3: 0,6V
* TP2 to T1 Pin 7: 0V

Hints:
* The kit was missing C3, which i then substitutet with a ceramic cap "n47" 100V. (see attached pic).


* RLY1 edge got burnt (see attached pic2). I don't remember if it was from soldering iron (unlikely) or due to faulty connection...




Thanks for you support & cheers from Austria

[JPK]

The burnt relay is very probably what causes the DI/Mic issue.
You need to replace it.
Mouser/Digikey: TQ2-24V
TME : AZ850-24

Sorry for the missing cap. If you have an other one, you could also replace C2. C2 and C3 must be similar for the best CMRR.