SSL xlogic alpha vhd pre phantom problem

[VanGenz]

I have two XLogic alpha VHD 4-channel preamps with defect 48 volt for repair. They have an external power with +/-15 & +5volt.
I have no schematics. The -15 volt i s ok but +15 falls to 13,3 an +5 falls to +3,9 after some seconds. The +48v is 0,4  on pin 2/3.
The +48v is comming from some kind of oscillator/transformer arrangement but I see no burned components nor find any shorted semiconductors with my Huntron tracker in the internal power. Anybody have any experience with these units or have schematics? I googled other with similar problems but no solution....

 

[12afael]

can you post a picture of the guts? could be useful to help you, do you have an osciloscope? you should check if the oscilator is working properly.

 

[pinebox]

I am having the same issue. I requested a schematic on another forum earlier today, if I get one I will be sure to post here. Included is a picture of the unit internals.

 

[VanGenz]

Problem solved! Main problem was 6 electrolyttic capasitors in the power that was starting to dry out. Change these. In one of the units a smd mosfet was shorted in the power. I will post this tomorrow. In bed now.....zzzzzzzz.

 

[VanGenz]

Chech the TR9 Component. Mine was nearly shorted between pin 1 and 3. The Component is called ZXMN6A08 (60 volt n-channel mosfet). Did not find this Component at Farnell but used ZXMN6A09GTA (Farnell number 7564988). But in one of mine defect units the only problem was defect capasitors. And you can see they are defect - round on the top.

 

[phantombox]

Hi.
I have this problem with my SSL as well.
The electrolitic caps on mine don't look to be dried out and they aren't inflated, either...
Did any of you receive the schematics for this pre? Would you mind mailing me a copy to [email protected]?

 

[phantombox]

48V measures 5.1V between pin 2/3 and pin1 on the XLR in.
Could you tell me which caps did you replace? Since this SSL is SM topology (typically) , I don't want to mess arround with it to much...