Hello all!

As the title explains, I'm trying to repair a power supply Brilux BZE-105. This is a power supply for indoor lights. It should convert 230 V AC to around 11 V AC.
Here's what I have already done and measured:
- I found schematics of the power supply, link: http://cxem.net/pitanie/images/5-346-17.jpg
- I opened the power supply and found that the 0,5 ohm resistor at input was burnt, so I went to local electronics store to buy it. Since I couldn't find rated power I assumed it was 1 W -> I assumed rated power by looking at it's size (about 11 mm long and 3 mm thick) -> store only had E12 resistor values so I bought 0,47 ohm
- unsoldered burnt resistor, replaced with the new
- resoldered input terminals, they were a bit loose
- tried to power it up and BOOM, the same resistor was blown so i'm back to where I started
- measured rh115-2 - it is in short, which is good since it is a thermal fuse
- measured some capacitors with voltmeter and they were all charging which is fine i guess
- did visual inspection and everything looks fine to me

I'm not even sure for what is this resistor for. Signal integrity? Current limiting? Should I put higher rated resistor (got 0,47 ohm 5 W at home)?

At this point I do not know what to look at and what to measure. Any tips or suggestions would suffice. Sorry for my English, it is not remarkable. I hope I explained my problem well.

Thanks in advance.

 

Why don't you just replace it with a 12V AC transformer psu.?

 

Check VD1-VD4, VT1 and VT2 for shorts.

 

I agree with Dd. The resistor that you replaced should only have been replaced with a fusible resistor. (It behaves as a fuse as well a s a resistor.) It will probably cost you more for parts to fix it as more than one component normaly fails in this type of power supply and if you don't replace ALL the faulty components it will blow up again. Here is one example of a suitable replacement power supply.

Les.

 

Why don't you just replace it with a 12V AC transformer psu.?

Well I had some spare time and I wanted to repaired it. . You know, just to have something to play around. But yes, this is my alternative.

Check VD1-VD4, VT1 and VT2 for shorts.

VT-1 and VT-2 have shorted base and emmitor. Is this a problem?
Oh yeah. One of the full bridge rectifier diodes is shorted. I think I have some of 1N4007 lying around.
Great suggestion.
Thank you. I also checked other diodes, everythings looks to be fine.

 

I agree with Dd. The resistor that you replaced should only have been replaced with a fusible resistor. (It behaves as a fuse as well a s a resistor.) It will probably cost you more for parts to fix it as more than one component normaly fails in this type of power supply and if you don't replace ALL the faulty components it will blow up again. Here is one example of a suitable replacement power supply.

Les.

You two are right indeed. I just want to repair stuff. Thank you anyway.

 

VT-1 and VT-2 have shorted base and emmitor. Is this a problem?

They should read 3.7Ω in circuit because of the resistors and inductor connected.

 

They should read 3.7Ω in circuit because of the resistors and inductor connected.

I measured 4,7Ω. I guees this is fine. Also I have a crappy multimeter so maybe it is a bit off.
Didn't found any spare diodes. I will go purchase them tommorow.

 

I measured 4,7Ω. I guees this is fine. Also I have a crappy multimeter so maybe it is a bit off.
Didn't found any spare diodes. I will go purchase them tommorow.

That shorted diode would blow the resistor. You might be lucky and everything else will be OK.

 

So, I replaced diode and resistor, pluged it in and again BAAM.
Now I have two dead diodes (VD1-VD4), input 0,47Ω resistor burnt and thermal fuse exploded. hehe.
Since I can't buy RH115-2 from Farnell or Digikey, will EYP2BH115 fuse do it's job? Or could I just short the fuse? But I think this is not the best idea.
Is something else wrong? I checked all the other resistors and they are all fine, all capacitors are fine, VT1 and VT2 are fine.

 

Is this with the lights connected?
make sure the lights or wiring to them isn't short.
Can you check the lights with a different supply?

I don't know what the supply will do if there is no load so don't try it with nothing connected.

 

Is this with the lights connected?
make sure the lights or wiring to them isn't short.
Can you check the lights with a different supply?

I don't know what the supply will do if there is no load so don't try it with nothing connected.

I had no lights connected to the power supply. I pluged it in with no load. You think that this kind of power supply could broke if there is no load on it? I think that is not the case here.
I tested all of the lights and they are all working.
I will give it one more try. I will replace thermal fuse, and other components and try to power it again. If it fails then trash it is.