Uni SMPS 300W

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Bolasha

New member
sakisalfista said:
Is the trafo vibrating? Did you glued the core?
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Yes. I glued too.

I'll try to point the effects and the circunstances:

- Using inductor before output capacitors, I only get HISSSS when I drain a lot of current, but, the problem is that the voltage drops A LOT, like, from 48 to 40 even with a small load (50w).
- Without inductor, when I apply load, the voltage RISES. I used original EI33 from ATX PSU, first it was 42v, with load it rose to 47! With more load it went to 52 almost blowing up my capacitors. And HISSING.

The trafo that was vibrating with no load was too strong, like only 28 turns on the primary. With the other only vibrates with load.
 
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sakisalfista

New member
Change your capacitors with higher voltage and give an even bigger load without inductors. The voltage should be stabilized at some point. Then with bigger load it will start to decrease like normal. I am saying this because I noticed that you have no balancing resistors on the output. I am not sure if it will work 100% on your case. And take safety precautions like goggles and try to keep a distance cause transistors like to blow up! ��
 
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sakisalfista

New member
Probably your transistors misfiring. Check your drive Trafo windings. What about adding a diode in front of the base in parallel with the capacitor? ��
 
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Bolasha

New member
I'm using the E16 original, this one that you post is toroid from CCFL lamp right? Can I do it with E16 rewounded?
 
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sakisalfista

New member
Well the circuit works with non rewounded trafo. You also have oscillation so the windings polarity are as they should. An oscilloscope would be much helpful right now. ��
 
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sakisalfista

New member
I have made 3 different smps but with another self oscillating configuration like the one used from detex audio. They all worked very well with minimum voltage drop. You are very close but you are missing a detail from completion. :/
 
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Bolasha

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Yes I had, thanks for asking!

It's working fine with inductor, the voltage is lower than original with it but the drop with load is smaller too.
I'm getting 40+40 and 35+35 with high load.

The only problem I can see now Is that if I use it with amplifier and use a cellphone as audio source, the touch gets crazy. Any tips on it?
 
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sakisalfista

New member
In my smps output ground is connected directly to the line ground. This helps . Maybe you should start with a 100nf capacitor first and use an mp3 player as audio input, I would not try to use my cellphone as audio source. I have burn 2 mp3 players accidentally by touching their body ground to an uninsulated heatseank from a tda7294. (- 35volts in this case) :D A cheap mp3 or a Bluetooth receiver as a start is a better choice.
 
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fan34574

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so i made the circuit using 2 13005 transistors and as soon as i plugged everything in bam the 150k ohm resistors at the rectifier end blew up. i immediatly plugged the circuit off then plugged it again (stupid i know) however both the transistors got really hot quickly and there was no output at the secondary of the ee33. (i used the half bridge one at the beginning of this thread), any ideas as to why this happened or a proposed fix maybe?

thanks in advance
 
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Bolasha

New member
First, if the 150k blew up, you probably made a mistake choosing them, they might be like 15k or even worse.

Have you checked the primary of T2? You can reverse it for trying.

Put a resistor and a led on the output of your transformer, I had lots of problems to measure the output frequency with multimeters. (Analogic works fine)

As soon as I finish my tests to 100% I'll post my pcb.
 
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