Hi, there!
A friend asked me to have a look in his SE Z5600aII PSU as he had audio cuts when moving it.
First I thought that the cable was faulty and checked each pin with a continuity test: fully functional.
Then I considered that a cold joint could be the cause and decided to look for bad ones under the PCB.
I replaced all ugly and mat joints with fresh tin and it seems it was the cure.
But...
Since then, another problem occured: PSU does not supply any 180v!
I made a quick layout of the board (top view) that I attached to this post.
As you can see, 180v supplied at brown point (right bottom corner) comes from JCQ3F relay at normally open (N.O.) pin.
The circuit between relay's COM and N.O. is closed when a 12v current come across this relay at pins - and + .
This current is provided by a 7812 named IC3 (right top corner), and is measured at about 11, 7v which should be ok.
Unfortunately, only 10,8v is measured between pins - and + of the relay, so 180v can't be provided to the mic.
How could this current be closer to 12v?
Which component could be faulty?
Just for my own curiosity, I replaced IC3 by a 7815 to see if the relay was a part of the problem, and everything turned fine.
Except that I measured 193,4v instead of 180v...
Thanks for your help!
A friend asked me to have a look in his SE Z5600aII PSU as he had audio cuts when moving it.
First I thought that the cable was faulty and checked each pin with a continuity test: fully functional.
Then I considered that a cold joint could be the cause and decided to look for bad ones under the PCB.
I replaced all ugly and mat joints with fresh tin and it seems it was the cure.
But...
Since then, another problem occured: PSU does not supply any 180v!
I made a quick layout of the board (top view) that I attached to this post.
As you can see, 180v supplied at brown point (right bottom corner) comes from JCQ3F relay at normally open (N.O.) pin.
The circuit between relay's COM and N.O. is closed when a 12v current come across this relay at pins - and + .
This current is provided by a 7812 named IC3 (right top corner), and is measured at about 11, 7v which should be ok.
Unfortunately, only 10,8v is measured between pins - and + of the relay, so 180v can't be provided to the mic.
How could this current be closer to 12v?
Which component could be faulty?
Just for my own curiosity, I replaced IC3 by a 7815 to see if the relay was a part of the problem, and everything turned fine.
Except that I measured 193,4v instead of 180v...
Thanks for your help!
