Focal Cub 3 won't turn on

[frankie]

Hi everybody !

First post in this nice forum I've just discovered !


Here is my problem : my subwoofer can not turn on.

This is a Focal Cub 3 model : "BASH technology : both AB and D-class amplifier !"


I found some weird resistors on a little pcb soldered on the main one :




This little card seems to drive the 2 MOSFET before the main transformer.

So I changed all the resitors + 3 diodes (red marks on the following picture).

You can see the measured voltages on the 8-pin little card, too:



When I try the amp => always the same problem = no square signal on the two MOSFET gate before the transformer...


Nothing on the 3 last pins. The 5th pin drives one MOSFET gate and the 8th pin drives the gate of the second MOSFET.



After measuring many voltages and signal with both my multimeter and my scope, I realized that the amp worked !!





So I measured all the voltages again : nice square waves on the 5th and the 8th pins !!!

After powering off and on the amp, nothing again...

Currently it still doesn't work...


What do you think about it ? Is it possible that I made the circuit oscillate with one of my probes ?


Which component of the SMPS could be bad ?


Thanks a lot for your help !

Frank.

 

[MicrosiM]

This thread should be of more help to you


http://www.diysmps.com/forums/showthread.php?188-Klipsch-Bash-SMPS-DIY-Rebuild&highlight=bash

 

[frankie]

Hello everybody,

I changed almost all components on the little INDIGO pcb except the DIAC I can not find easily.

The unit still doesn't work...

Maybe the answer is elsewhere ?


I'm wondering what is the purpose of an area of the main pcb : the 240V is directly connected thru 2 capacitors to the secondary.

Here are the top view and the bottom view of this part.



According to you what should I measure in the different areas of this part ? Currently I have 0V between the GND and the OUT pins of both regulators.


Any help will be appreciated.

Thanks a lot !

 

[frankie]

Hello everybody,

I changed almost all components on the little INDIGO pcb except the DIAC I can not find easily.

The unit still doesn't work...

Maybe the answer is elsewhere ?


I'm wondering what is the purpose of an area of the main pcb : the 240V is directly connected thru 2 capacitors to the secondary.

Here are the top view and the bottom view of this part.



According to you what should I measure in the different areas of this part ? Currently I have 0V between the GND and the OUT pins of both regulators.


Any help will be appreciated.

Thanks a lot !