Uni SMPS 300W
- Thread starter Acca
- Start date
that maybe true but i cant confirm since they are charred:ambivalence:. so if i change them in for another high wattage ones, should the circuit just work as fine ? or should i too change the transistors, assuming that they have been damaged?
if that doesnot work then ill reverse the primary as you suggested. and i did try using a filament lamp at the end of the output just to see if anything il happen, however it didnot light up what so ever. ill look forward for your design then
thanks in advance
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sakisalfista
New member
Always put an 100 watt or more incandescent lamp in series for the first time .
Transistors probably need to be changed too, you can test them before.that maybe true but i cant confirm since they are charred:ambivalence:. so if i change them in for another high wattage ones, should the circuit just work as fine ? or should i too change the transistors, assuming that they have been damaged?
if that doesnot work then ill reverse the primary as you suggested. and i did try using a filament lamp at the end of the output just to see if anything il happen, however it didnot light up what so ever. ill look forward for your design then
thanks in advance
If you use 150k it shouldn't be a problem even with 1/4w.
soooo i did like you said, changed the resistoes and checked the transistors, surprisingly they were intact plugged it in into 120v outlet (cuz I didn't wanna try 230 yet) okay the bulb glowed and no explosion but no output. try as i may nope i got nothing. so i was like okay maybe the input Voltage was the problem, (eventhough i knew it was ridiculous) i plugged it into 230v..../ bam explosion and bam tripped my house fuse.plugged it into 120v everything is same as it was plugged in before. i am honestly confused as to what just happened. idk what am i doing wrong. ( also there were no explosion marks on the board)
plugged it in into 120v outlet (cuz I didn't wanna try 230 yet) okay the bulb glowed and no explosion but no output. try as i may nope i got nothing. so i was like okay maybe the input Voltage was the problem, (eventhough i knew it was ridiculous) i plugged it into 230v..../ bam explosion and bam tripped my house fuse.plugged it into 120v everything is same as it was plugged in before. i am honestly confused as to what just happened. idk what am i doing wrong. ( also there were no explosion marks on the board)sakisalfista
New member
An incandescent lamp should always be in series with the input line. If you want to put also a second on the transformers output that is ok . But the first load tests should be with the primary lamp on . The lamp will start light up as you increase the load and there should be a significant voltage drop that will be gone once you finally remove it. With no load at output the lamp will glow instantly because the capacitors will charge up and then it should be almost like closed.
As Sakis said, you MUST use a light bulb in series.
If your transistors are fine, you probably have a short in the entrance of your circuit, check it again. The bulb must not be glowing after you turn it on!
Check the video that I posted a page back, the bulb is glowing because I'm draining power, then I put it on the 220v mains
If your transistors are fine, you probably have a short in the entrance of your circuit, check it again. The bulb must not be glowing after you turn it on!
Check the video that I posted a page back, the bulb is glowing because I'm draining power, then I put it on the 220v mains
i desoldered everything and i used newer transistors that i checked forehand as well. i used another good looking, and seemingly undamaged e16 transformer.i spent more time soldering the circuit board made sure the connections are right...... however when i plugged things in the input fuse blew off. it was a 3.7A one and there was no load on the output.i am providing pics of my board ( it's a bit wacky but i ran out of pref board since i used what remained for the first circuit) incase any of few gentlemen would be able to find any fault in the actual soldering. i have used the b2 circuit board layout, none of the transformers were rewound , they were used as is from the extracted ATX PSU. i used an ee35 instead of the ei33 that i had installed earlier on the previous board http://imgur.com/a/8FyMd ( i didnot know how to upload multiple files so i uploaded it on this link). the white wires are for the mains.
thanks alot for your time
thanks alot for your time
any of you gentelmen*
i also didnot use the input caps or the filter at the beginning of the mains input- i just thought they were slightly not that detrimental since most of the filtering is done on the rectifier end any was- instead the live connected to the fuse which connected to one pin of the input, the other pin of the cap is connected to the neutral. the cap is in parallel to the ac input line of the rectifier.it'd be really awesome if someone would be able to guide me step by step as to what i should do to fix it. i have went 5 times over this thread and tried my best to understand what it is that is going on but i donot seem to find that my problem has been mentioned before.
thanks a alot again
i also didnot use the input caps or the filter at the beginning of the mains input- i just thought they were slightly not that detrimental since most of the filtering is done on the rectifier end any was- instead the live connected to the fuse which connected to one pin of the input, the other pin of the cap is connected to the neutral. the cap is in parallel to the ac input line of the rectifier.it'd be really awesome if someone would be able to guide me step by step as to what i should do to fix it. i have went 5 times over this thread and tried my best to understand what it is that is going on but i donot seem to find that my problem has been mentioned before.
thanks a alot again
Silvio
Well-known member
any of you gentelmen*
i also didnot use the input caps or the filter at the beginning of the mains input- i just thought they were slightly not that detrimental since most of the filtering is done on the rectifier end any was- instead the live connected to the fuse which connected to one pin of the input, the other pin of the cap is connected to the neutral. the cap is in parallel to the ac input line of the rectifier.it'd be really awesome if someone would be able to guide me step by step as to what i should do to fix it. i have went 5 times over this thread and tried my best to understand what it is that is going on but i donot seem to find that my problem has been mentioned before.
thanks a alot again
I think you have a problem in the input. Firstly try to disconnect the rest of the circuit after the bridge and main bulk capacitor and energize them alone to see if there is something wrong with your input stage.
Put a series lamp with the input (instead of the fuse) and never work without it until you get your supply oscillating otherwise if you have something wrong you will damage components. The bulb should glow at first then it should turn off again with the supply having no load.
Check your circuit section by section for wrong polarity. check also your bridge rectifier and see if it is still good
arrange your circuit neatly and try to use insulated wires for joining up it will help prevent short circuits
One last note be careful and try not to work with grid mains as it is lethal and will kill you. Use an isolation transformer
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alrighty good news is no explosions, yaaaaay!! bad news is no output on the ee35. as soon as i plug the circuit in the 100w lamp lights up then quickly fades away, which is good....i think ( well better than fireworks afterall lol ). any ideas as to how i could fix this?
i can't really thank you all enough for the awesome support you gave me thanx alot
( well better than fireworks afterall lol ). any ideas as to how i could fix this? i can't really thank you all enough for the awesome support you gave me
thanx alotalrighty good news is no explosions, yaaaaay!! bad news is no output on the ee35. as soon as i plug the circuit in the 100w lamp lights up then quickly fades away, which is good....i think
i can't really thank you all enough for the awesome support you gave me
alright update here so i somewhat fixed it but as always there has to be something that is not right.i can hear the transformer producing a tak tak tak voice which decreases in volume when i add a load in the secondary. there is an output current on the secondary however when i tried connecting a 5 watt light bulb across the secondary, it doesnot light up i only get small sparks upon touching the terminals. the voltage across the primary is 360V even though my input for the circuit is 230 V. i tried switching the feedback winding same thing no change at all.i am aware that a similar issue to this has been at post #46 however there doesnot seem to be adequate an explanation as to how i can fix it
thanks alot again in advance
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You're on the right way! This problem you are having I solved with a good inductor before output capacitors.
Take a look at the last prototype I made:
[video]https://youtu.be/xtM6A7p6Skg[/video]
I also have 2 problems:
1 - It makes a tac tac tac when you turn off while the capacitors are discharging.
2 - Touch screens get crazy when working together with the smps.
Silvio
Well-known member
Hi did you check the oscillating frequency? It could be running too high and the trafo gives poor output
Regards,
Silvio
Silvio
Well-known member
It could be both if frequency is low according to the number of turns in primary of trafo your B in the core will be too high and will get the core hot.
if the frequency is high the output power will suffer as switching losses tend to heat up the core and also the transistors.