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PS12015 power supply, from Velleman and others, LM723 based

Started by Sonnich Jensen June 18, 2016
Hi

I have one of these - got it for free:

http://www.velleman.eu/products/view/?country=fr&lang=en&id=349761

Mine is from EQ, but it is one product with many labels.

It works - but...
However, there is a burnt diode, V5, which probably was meant for inverse protection - however that diode short circuits the output ???? and the capacitor there is reversed?????

I need to either ask for a schmatic or draw one myself - does anybody here have a schematic of that thing?


Secondly, just a tought, there is 24V on the main capacitor, so in stead of 1.2-12V I could raise this to say 18V - once I have the schematic. Has anyone done this?

WBR
Sonnich
On Saturday, June 18, 2016 at 1:27:27 AM UTC-7, Sonnich Jensen wrote:

> I have one of these - got it for free: > > http://www.velleman.eu/products/view/?country=fr&lang=en&id=349761
> I need to either ask for a schmatic or draw one myself - does anybody here have a schematic of that thing?
The app circuits in this datasheet <http://www.ti.com/lit/ds/symlink/lm723.pdf> are a good place to start. I'd suggest figure 20 is a likely schematic, but you'll have to verify the heatsinked pass transistor (NPN or PNP) gender.
On Saturday, June 18, 2016 at 8:46:25 PM UTC+3, whit3rd wrote:
> On Saturday, June 18, 2016 at 1:27:27 AM UTC-7, Sonnich Jensen wrote: > > > I have one of these - got it for free: > > > > http://www.velleman.eu/products/view/?country=fr&lang=en&id=349761 > > > I need to either ask for a schmatic or draw one myself - does anybody here have a schematic of that thing? > > The app circuits in this datasheet > > <http://www.ti.com/lit/ds/symlink/lm723.pdf> > > are a good place to start. I'd suggest figure 20 is a likely schematic, but you'll have to > verify the heatsinked pass transistor (NPN or PNP) gender.
It is not I was up for a surprise - or 2 The reason why my original repair didnt work, was because my diode was broken - so it was doomed to fail. However, I did get a schematic, and this is where it gets weird. It is not in the datasheet and not to be found on the net. The use the Vref directly to the pot, and both sides goes to inv and non-inv by some divider resistors. The Vout is connected to a 6.2V zener, and the driving part is on Vc which drives an PNP. I tried to understand it, and just put in a new diode and closed it...