audioguru2
- Apr 6, 2004
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FireFly,
Yes, the 44V rated TLE2141CP is a good substitute for the TL081 in this project.
Yes, the 44V rated TLE2141CP is a good substitute for the TL081 in this project.
Ok People I fixed it 
So take this as a tip:
IF IT varies the voltage from 23v to 35v ONLY, you got the Emitter and Collector of the 2N3055 Mixed UP lol..
Cheers!! when I arrive home I will post some pictures if the administrator lets me (until I arrive home I hope the administrator will already have posted if I can post pics or not)
10x
So take this as a tip:
IF IT varies the voltage from 23v to 35v ONLY, you got the Emitter and Collector of the 2N3055 Mixed UP lol..
Cheers!! when I arrive home I will post some pictures if the administrator lets me (until I arrive home I hope the administrator will already have posted if I can post pics or not)
10x
audioguru2
- Apr 6, 2004
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Xenobius,
Good. I'm glad that you spotted and fixed your problem.
So the 2N3055's emitter-base junction was avalanching like a zener diode, in series with the base-collector junction. No matter what voltage the output of U2 was providing, the output could not follow it down.
Now you can remove those fuses which reduce the supply's performance:
1) Remove the fuse at the transformer's secondary, since its resistance limits the huge momentary current through the rectifiers when they charge C1, when the supply is loaded.
2) Remove the output fuse, since its resistance spoils the supply's regulation, when the supply is loaded. This supply has an adjustable current-limit so the fuse is not necessary.
Xenobius, could you please measure the voltage across R1/C1 without any load, and again set to 30V with a 3A load?
Good. I'm glad that you spotted and fixed your problem.
So the 2N3055's emitter-base junction was avalanching like a zener diode, in series with the base-collector junction. No matter what voltage the output of U2 was providing, the output could not follow it down.
Now you can remove those fuses which reduce the supply's performance:
1) Remove the fuse at the transformer's secondary, since its resistance limits the huge momentary current through the rectifiers when they charge C1, when the supply is loaded.
2) Remove the output fuse, since its resistance spoils the supply's regulation, when the supply is loaded. This supply has an adjustable current-limit so the fuse is not necessary.
Xenobius, could you please measure the voltage across R1/C1 without any load, and again set to 30V with a 3A load?
And one more substitution please: 2N2219
I can't seem to locate these in a form easily attachable to a heat sink. Can someone suggest another model(s) suitable for this circuit that would be easier to find in a "heat sink form" such as TO-220?
Thanks again (for the umteenth time!)
I can't seem to locate these in a form easily attachable to a heat sink. Can someone suggest another model(s) suitable for this circuit that would be easier to find in a "heat sink form" such as TO-220?
Thanks again (for the umteenth time!)
audioguru2
- Apr 6, 2004
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Firefly,
Use a TIP29 or TIP31 to replace the 2N2219. Their TO220 case can be bolted to a good heatsink.
Since their current gain is less, change R15 to 100 ohms.
Use a TIP29 or TIP31 to replace the 2N2219. Their TO220 case can be bolted to a good heatsink.
Since their current gain is less, change R15 to 100 ohms.
Hi all this is my PSU from inside.
How can I check the max current without a load?
thanks
View attachment 35406
How can I check the max current without a load?
thanks
View attachment 35406
Last edited by a moderator:
Hehe thanks buddy for the compliments and sorry for the 50w resistor because I don't have one.
Here is another picture of it so even the people who are going to build it will have an idea of the layout (sorry for the dirt on the table but I was just drilling a PCB lol)
View attachment 35408
and sorry for the 50w resistor because I don't have one. Here is another picture of it so even the people who are going to build it will have an idea of the layout
(sorry for the dirt on the table but I was just drilling a PCB lol)View attachment 35408
Last edited by a moderator:
I'm aware that the filter cap is recommended to be much larger uF wise but I'm wondering about the voltage rating. The original part list called for a 50V cap. I may have found some large-enough, 250V caps. Would using caps with much higher voltage ratings do anything good or bad to this power supply? Should they perform as well as the same size cap rated at 50V? There must be some kind of trade off. Perhaps physical size or cost?
audioguru2
- Apr 6, 2004
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To All,
See the other post about fixing this project before simply modifying it for 5A output.
See the other post about fixing this project before simply modifying it for 5A output.
Hi! ... i'm new on this forum so i have some maybe allreday answered questions... sorry
i'm wondering if someone has made a 5Amp modification and use the LM338 insted of LM317? is there a new PCB for that or something? Tell me what u changed...
I'm also thinking to do a dual power supply. that's two adjustable power sources. Can I build two PCB's and then use transformer whit "double secondary connectors".. i hope u know what I mean... and use it like that whit no further modification...
Thank you!
i'm wondering if someone has made a 5Amp modification and use the LM338 insted of LM317? is there a new PCB for that or something? Tell me what u changed...
I'm also thinking to do a dual power supply. that's two adjustable power sources. Can I build two PCB's and then use transformer whit "double secondary connectors".. i hope u know what I mean... and use it like that whit no further modification...
Thank you!
