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

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#45
The point where the trace feeding the primary center-tap gets narrow needs to be widened or reinforced (with a wire soldered to the board). It's likely to burn open there when the supply is stressed.

Without the circuit board designations on the board and without the schematic diagram, it's difficult to make suggestions.
 
#48
In fact i don't know, maybe i would like just to be sure that the supply is correctly build, because i don't want to buy components and build them if there is a risk to destroy all 😱

the big difficulties for me was to design the Tl494cn IC with all components with are attached with it.

I spent 3 weekend on it ! now i would like to finish it and build it 🙂

if you want the schematics Where can i send you it please ?
 
#50
When you build something like this, especially if you don't have much experience, you don't install all of the parts and then apply direct power. After you etch the board, install all of the jumpers, resistors and capacitors.

Connect it to a power supply as you normally would. Initially, use a 3 amp fuse to protect the components. Confirm that you have 12v on pins 8, 11 and 12 of the 494 and no other pins.

If that's OK, install the IC and see if it produces output pulses. If it does not, let us know. If it does produce pulses, confirm that you have clean a clean drive signal on the gate pads for all of the power supply FETs.

Do you have the transformer wound yet?
 
#58
I need your help please.

What resistor i need to buy for this supply please ?

mosfet are IRfz44N, output diode are C25-02C and C25-02N output voltage is 2x27Volts and fuse 2x25A

I think a 250mw resistors is enough for the tl494Cn IC ?

otherwise i must buy 3 transistors A1266 and 2 C3198 but i can't find them do you know about any replacements parts please ?

thanks in advance 🙂
 
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