Author Topic: Linear PSU question  (Read 548 times)

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Offline Hrvoje_CROTopic starter

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Linear PSU question
« on: November 09, 2024, 02:19:22 pm »
Hi!

I have purchased for a cheap (20euros) a power supply made by unknown brand. The unit has a 1 analog instrument which shows voltage/current.
So the main question is why does my psu behave like shown in a video? I mean, why voltage jumps to the max. value during the powering the unit off?

https://easyupload.io/g4favk

Thank you and sorry for shaky video.

Hrvoje

 

Offline IanJ

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Re: Linear PSU question
« Reply #1 on: November 09, 2024, 02:30:38 pm »
No video, just a bunch of Ads and a link to some dodgy software.
Try YouTube or Odysee.

Ian.
Ian Johnston - Original designer of the PDVS2mini || Author of WinGPIB
Website: www.ianjohnston.com
YouTube: www.youtube.com/user/IanScottJohnston, Odysee: https://odysee.com/@IanScottJohnston, Twitter(X): https://twitter.com/IanSJohnston, Github: https://github.com/Ian-Johnston?tab=repositories
 

Offline Hrvoje_CROTopic starter

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Re: Linear PSU question
« Reply #2 on: November 09, 2024, 04:00:32 pm »
Hi Ian!

Try it download from https://files.fm/u/f2x6wgwzbg here.

Thank you!

Kind Regards,
Hrvoje
 

Offline tunk

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Re: Linear PSU question
« Reply #3 on: November 09, 2024, 04:31:40 pm »
There may be stored some energy in a capacitor.
Try to put a load on it, e.g. an 1k resistor.
Photos of the inside may help understanding how it works.
 
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Offline Hrvoje_CROTopic starter

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Re: Linear PSU question
« Reply #4 on: November 09, 2024, 04:56:48 pm »
There may be stored some energy in a capacitor.
Try to put a load on it, e.g. an 1k resistor.
Photos of the inside may help understanding how it works.

I agree! Tomorrow i will post some pics ;)
 

Offline u666sa

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Re: Linear PSU question
« Reply #5 on: November 10, 2024, 11:24:14 am »
why does my psu behave like shown in a video
Broken. My YaXun PS-1501A from the times of before Noah's ark slowly goes down to 0 when turned off. That's what yours should be doing. Most likely some caps are bad on yours. Easy to check visually. If nothing seen visually, LCR or replace everything.
 

Offline George Edmonds

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Re: Linear PSU question
« Reply #6 on: November 10, 2024, 11:42:03 am »
Hi

Quite a number of bench power supplies go well over set voltage at either swirch On or Off.

There are a number of well know and expensive makes that do so, disconect load before switch On or Off.

G Edmonds
 
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Offline Hrvoje_CROTopic starter

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Re: Linear PSU question
« Reply #7 on: November 10, 2024, 12:07:45 pm »
why does my psu behave like shown in a video
Broken. My YaXun PS-1501A from the times of before Noah's ark slowly goes down to 0 when turned off. That's what yours should be doing. Most likely some caps are bad on yours. Easy to check visually. If nothing seen visually, LCR or replace everything.

Hi George!

Agree, but partially, psu works fine otherwise. But it is old cca. 30yrs. I will post some pictures in a few moments.

Regards,
Hrvoje
 

Offline Hrvoje_CROTopic starter

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Re: Linear PSU question
« Reply #8 on: November 10, 2024, 01:19:32 pm »
Here are the some pics of the unit itself:

 


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