305D power supply issue. - Page 1
Forum section: electronics / repair

author: jknightandkarr
author_rank: Contributor
timestamp: January 25, 2020, 10:22:44 am
content: 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.

author: jknightandkarr
author_rank: Contributor
timestamp: January 27, 2020, 07:41:50 am
content: 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..

author: dietert1
author_rank: Super Contributor
timestamp: January 27, 2020, 08:11:15 am
content: 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, DieterPS: Another thread is herehttps://www.eevblog.com/forum/repair/new-power-supply-ps305d-not-regulating-and-running-over-voltage-and-current/msg692302/#msg692302

author: shakalnokturn
author_rank: Super Contributor
timestamp: January 27, 2020, 09:36:25 am
content: 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.

author: dietert1
author_rank: Super Contributor
timestamp: January 27, 2020, 10:46:33 am
content: 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

author: jknightandkarr
author_rank: Contributor
timestamp: January 29, 2020, 07:10:03 am
content: 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.

author: jknightandkarr
author_rank: Contributor
timestamp: February 13, 2020, 07:21:38 pm
content: 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

author: goaty
author_rank: Regular Contributor
timestamp: February 14, 2020, 08:46:21 am
content: Quote from: dietert1 on January 27, 2020, 08:11:15 amAnd don´t even try 1V at 5A ;-)

author: Haenk
author_rank: Super Contributor
timestamp: February 14, 2020, 09:10:08 am
content: 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.

author: jknightandkarr
author_rank: Contributor
timestamp: February 17, 2020, 06:20:34 am
content: Quote from: Haenk on February 14, 2020, 09:10:08 amI will check for any of those. Thanks for the tip.