305D power supply issue.

[jknightandkarr]

I have the power supply below, Just has 305D as a model no. No brand marks that i can find, but I found a similar looking one on here already. Longwei PS-305D and was currious as to if there was any other makers of units like this? I got the scematics for the Longwei, but wanna check my power supply for issue components. Voltage isn't staying constant and jumps around from 3v down to 0.8 volts under no load and when knobs turned down it should be 0.0 & 0.0 but it won't go cut power unless i turn unit off. So wanna check it vs buying another since I don't have much money and am doing DeVry online school for electronics. Added photo of inside since it could be different fron the  other one. Thanks.

[jknightandkarr]

Well main pcb has Youde305xdv2. Searching has given 0 results.  Think I outta just buy a new and brand name one...

Edit: Don't know what I did, which was nothing other then taking pcb's out and shorting the big black cap to drain it n wiggling wires...... Now the unit is fine again..

[dietert1]

What is this? Is this meant to be a switcher or a linear supply? Couldn't see the inductor for a switcher nor a proper cooler for a linear regulator. I guess it's some kind of fantasy product that won't last a single minute at 15V 5A. Using this you may risk fire in your lab.

Regards, Dieter

PS: Another thread is here  https://www.eevblog.com/forum/repair/new-power-supply-ps305d-not-regulating-and-running-over-voltage-and-current/msg692302/#msg692302

[shakalnokturn]

Linear... The errr... "heatsink" is mounted right behind a fan.
Great value for money as long as you don't really plan on using them.

[dietert1]

This one appears similar but different from a longwei power supply. It does not even have the color coded binding posts, nor the green power switch.

Regards, Dieter

[jknightandkarr]

Actually already considering other options, since wiggling wires and shorting the large cap somehow fixed it.... Looking at this setup from one of Dave's past videos.  Will use this current thing very little or for a DIY powersupply project.

 

[jknightandkarr]

Yeah. My power supply is deffinatly trash.... hasn't been used since i was playing around inside, turn up voltage n back down and now stops functioning till i turn off and back on..... junk

[goaty]

... won't last a single minute at 15V 5A.

And don´t even try 1V at 5A ;-)

[Haenk]

In a review of one of the many "clones" (probably OEM'ed by the same company), cold solder joints have been found. If you want to keep it, I'd look for that. I don't think that your PSU is broken as in "component failure", but broken as in "broken solder joint", probably a 5min fix...
Can't really beat a linear power supply for that little money (I actually have two of those), buying the components alone would certainly be more expensive.

[jknightandkarr]

In a review of one of the many "clones" (probably OEM'ed by the same company), cold solder joints have been found. If you want to keep it, I'd look for that. I don't think that your PSU is broken as in "component failure", but broken as in "broken solder joint", probably a 5min fix...
Can't really beat a linear power supply for that little money (I actually have two of those), buying the components alone would certainly be more expensive.

I will check for any of those. Thanks for the tip.