Need help building a cheap ac dc adapter

[mikey5791]

Found these two pcb from my junk bin and unsure if i can reuse them to build an ac to dc adapter of 12vdc. If i remembered correctly, these pcbs could be from a damaged fluorescent light set box.
The first pcb is with 2A glass fuse, 4 pieces 1N4007 diode, one black inductor, 2 pieces 22uf250v big cap, one blue 630v ceramic cap, 2 pieces green 104k ceramic cap, another 4 pieces 1N4007 diode and one brown MZ2 cap. To me, this looks like the primary supply in dc form.
The second pcb has 2 pieces 13005 transistor on the side mixed with resistors, 2 green 334k green ceramic caps and finally a ferrite core transformer.
I wish to modify and hopefully make a usable dc output adapter for testing on small electronic project , using either 5v or 12vdc and current capacity less than 1A. Looking forward for any guide and help from someone more experience in doing this.

[stj]

Re: Need help building a cheap ac dc adapter

the board with the transistors is a high voltage generator, you wont be using that!

the first board, try to draw a schematic

[eccerr0r]

Re: Need help building a cheap ac dc adapter

technically a high voltage generator could be reversed to produce a low voltage SMPS ...alas not easily, massive rewire necessary...

Question is, what else do you have? The massive rewire might be your only option if you have no other step down...

[mikey5791]

Re: Need help building a cheap ac dc adapter

the board with the transistors is a high voltage generator, you wont be using that!

the first board, try to draw a schematic

Trying my best effort to sketch a rough schematic. Looking at my attached image of the first pcb with the 2A glass fuse on the upper right side corner, i am labelling the diode nearest to fuse as D1, then next to it is D2. The last diode is D9 as shown on bottom of pcb. Hope this helps.

[stj]

Re: Need help building a cheap ac dc adapter

thats a strange circuit, the ground from D1,D2 never reaches the output side!

[petehall347]

Re: Need help building a cheap ac dc adapter

D7 D8 D9 look to be wired a bit odd to me

[harp]

Re: Need help building a cheap ac dc adapter

I dont know if this feets you, but I have simplest "bench power supply" for testing, only from one wall adapter and buck module with current limit capability. It work from about 1.8v to 12 and from 10mA to about 5A...