need help to build my own smps based on blaupunkt schematics gta400 please

[Ground Zero]

do you think i can put fet and transformer ?

 

[Perry Babin]

Install the FETs and post a photo of the signal you have on one of the gate pads (confirm that they are still identical after installing the FETs).

 

[Ground Zero]

This is the photo without fets

An externally hosted image should be here but it was not working when we last tested it.

This is the photo with four fets intalled, on each gates the signal is the same

An externally hosted image should be here but it was not working when we last tested it.

 

[Ground Zero]

Can i put the transformer ?

 

[Perry Babin]

Yes.

 

[Ground Zero]

ok i'll put it

Thanks Perry

 

[Ground Zero]

i can here a whistling after 10 or 15 second i power up the supply

what can i do ?

 

[Perry Babin]

Did it blow the 10 amp fuse?

What does the waveform look like on the gate and drain of the power supply FETs?

 

[Ground Zero]

no 10 amp fuse is ok !

but on the schematics they put resistor and condensator in serial ?? and i don't put them....and they are on primary of the transformer.

 

[Perry Babin]

They used a CLC filter in the Blaupunkt but it's not necessary.

What does the waveform look like on the gate and drain of the power supply FETs?

 

[Ground Zero]

i use le lcl filter and the noise disappear

the waveform on gate is

An externally hosted image should be here but it was not working when we last tested it.

the waveform on drain is

An externally hosted image should be here but it was not working when we last tested it.

i put rectifier diode and i have +27.5v and -27.9V without condensators on each rail.

without rectifiers the voltage on transformer is really important 108V at powerup

 

[Perry Babin]

Install the rail capacitors.

Virtually no amps use a CLC filter at the input. This power supply shouldn't need it. After installing the rail caps, remove the inductor and capacitor to see if it will make a difference.

 

[Ground Zero]

Ok thank Perry

I will remove the clc filter and put output capacitors

 

[Ground Zero]

I remove the clc filter and i put rail capacitor

It's strange the voltage go to 2x29.8 volts and grow up slowly to 2x30.1 ...2x30.2 etc i stop at 2x30.6 i dont know what is the problem ???

i also replace all resistor already use by new because old serve to test the smps

I have this to gate

An externally hosted image should be here but it was not working when we last tested it.

to drain

An externally hosted image should be here but it was not working when we last tested it.

Is it normal ?

 

[Perry Babin]

I don't understand what you're concerned about. Can you be more specific?

 

[Ground Zero]

Could you tell me if the squarewave is ok ?

for the output voltage why it growup

 

[Perry Babin]

The difference between 29.8 and 30.6 is insignificant.

Where was the black probe placed when you were measuring the voltage?

 

[Ground Zero]

the black prob is dirrectly on the output of the supply who power my supply

 

[Perry Babin]

Place the black probe on the secondary center-tap of the power transformer.

 

[Ground Zero]

Yes obviously I'm tired

Thanks Perry you are great