Power Suply Led Driver Repair Problem

[rodrigo.bernardo]

Hello everyone,

I am trying to repair a faulty power suplly for a LED Light.
I measure 0 V on the output so LED dont light up, however in the input (out of rectifier), I have 60 V, so the problem must be in the middle.
Capacitors seems to be good condition, diode is also good (I tested). No burn signals elsewhere.

I attached the pcb board and a shcematic that I draw from observing the PCB. Note that there is an IC with the letters "BVYDLA" (I think its that)... its the only thing I found written on IC.
I cant find datasheets of this PCB.

Thanks for everyones help. Every tip I can get to found the problem or to identify the IC is welcome.

[stj]

check the input to the rectifier.
you should have 230v ac going in and about 340v dc coming out.
if it was an overload the rectifier would explode or the fuse would blow - so it's not a problem after the rectifier.
it's the rectifier or something before it - maybe the fuseable resistor in heatshrink is bad

[rodrigo.bernardo]

Sorry, on the output of rectifier I have also 26 V when measuring in DC mode. On the input of rectifier I measure 26 V. If you look at one of the photos, you can see that between the two oxide varistors, there is a transformer that stepsdown the input AC voltage. The fuse resistor its fine. On the input of transformer I measure 230 V AC.
Thanks for your reply

[Per Hansson]

"If you look at one of the photos, you can see that between the two oxide varistors, there is a transformer that stepsdown the input AC voltage."
That is an inductor, it is just for common mode interference reduction, it does not change the AC voltage.
Do you really have 230VAC before that component and then 26VAC after it?

[CapLeaker]

Hmm... Something is fishy with this measurement. Verify your AC measurement going to the bridge rectifier and your DC measurement leaving the bridge rectifier. Being both the same voltage, I am not buying it.
I suggest you check continuity on each leg from the AC side to the bridge rectifier. If there is an open, it will show.