ATTEN APS3003S Bench Power Supply

David_AVD

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I needed a variable power supply to use at home when testing various boards, pixels, etc. On eBay I found the ATTEN APS3003S bench power supply for $95 delivered. I also saw them for the same price on AliExpress, but I don't recall if postage was free.

I was pleasantly surprised by the overall build quality. The output voltage (measured with a Fluke DMM) was spot on too. The output is adjustable from 0 to almost 33V and the maximum output current is 3 Amps. Here's what it looks like without the cover.



The only negative is the noise from the cooling fan. As I was not drawing much current at all for today's project, I disconnected the fan. I'll probably make up a little PCB to switch the fan on only when the heat sink goes over a certain temperature.

Anyway, I thought I'd present this mini review in case anyone else was looking for a cheap variable power supply for testing strings and general workshop use.
 

Daemon

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Are you reading the temperature inside the case David?


I may try to whip up something based on the Atmega328 instead of a pic.
 

Daemon

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My power supply arrived today. I see what you mean about the fan noise, very loud.
I was unfortunate enough to get a chinese manual also so I am trolling the net for an english one before I can get on with using it.
Your board is looking good.
 

Daemon

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I can't quite see the markings but is that a thermister already attached to the heat sink David?
Is the circuit that is already in place not working correctly on the power supply?


Just wondering before I attempt to create something of my own.


As the fan seems to be full on all the time I assume it does not work and if I attach my circuit to the existing 12v fan output of the power supply then my circuit will be powered on all the time.
 

David_AVD

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My power supply has no provision for fan control at all, hence the need for my little board.

The fan is currently powered from an auxillary winding of the transformer via a diode bridge and filter capacitor.

I'm still in the process of finishing up the code and working out how to quieten the singing noise created by applying PWM to the fan. If that proves too hard, I'll just make it switch fully on and off (at the trip point) instead.
 

Daemon

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I was just reading up on what circuit to use and found one that has a pwm input but then goes to a filter and a fet to not apply pwm directly to the fan, something about reducing the pwm to a dc level to remove noise. Need to do further reading.
While I seem to have a thermister attached it doesn't do anything, the fan seems to be full on as soon as power is applied.
 

David_AVD

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I assume it's not the same model as mine? If not, the thermistor could be part of a protection circuit to shut the supply down if the heatsink gets too hot.
 

David_AVD

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I wrote some basic on/off code for the microcontroller and fitted the PCB to the heatsink.

The thermistor for sensing the heatsink temperature is soldered onto the back of the PCB and simple pressed against the heatsink.

I didn't have much hardware at home so the PCB is mounted using whatever I could find in my leftovers box!

 

Brownie

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How is your power supply controller going David? I have the ATTEN APS3005Si model and would also like to do the same thing. How much was the board and is it easy enough to install?
Brownie
 

David_AVD

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I designed and made the board myself and wrote some code to run on it. I do have some spare boards that I could make up, but I'd have to work out a price.
 

Daemon

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I too could look at getting one off you at the same time as the dmx candy cane controllers David.


Keep up the good work!


Steve
 
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