Voltcraft DPS-4005PFC repair/conversion log

[cat87]

Hello fellow EEV Bloggers,

I would like to share with you my most recent  project and that is an attempt to bring back to life a Voltcraft switchmode power supply.
More detailed information and pictures can be seen on my blog page:

http://electronicsplayground.blogspot.ro/2015/07/project-1.html

This thing will do 0-40 Volts and 0-5 Amps...when it has all its parts that is. This PSU unfortunately is missing some, most important of which are the two micro-controllers that take care of the LCD, the keys, the rotary knob and the ADC.



So, I decided to give this piece of german engineering a second change and get it working to full order. The Arduino is a nice solution to this, but the number of pins on my Leonardo is nowhere near the necessary to completely get this PSU working. But, for start, it'll have to do.
I plan a buying a Mega and having my way with that, after I get some things actually working.

So far, I've managed to get the knob working, the ADC, which is an AD7541, and the LCD, which was a real pain, but that's because I don't have the patience to read long datasheets. By the way, the LCD controller in this thing is an PCF8576 and some initial code for this can be found on my blog page.

The next step would be to wire in the Arduino Mega and see how all the bits and pieces fit together. Funny thing about this PSU is that the ADC drives both the voltage and the current limiting, so I thing this might actually be a matter of timing to get my voltage and current limit values just right. In the attached schematic, there are two caps, C29 and C30, that hold the ADC output  values for these. This is going to be interesting.



Anyway, I'll try to keep this post updated with my progress and hopefully, will soon have a working PSU.

[cat87]

And these are the pics that were supposed to be attached to my first post. Oops