The parts of electronic that probably fails most often seems to be the power panel. I cannot explain how sick I am of searching for broken parts at this panel.
Recently another machine of mine failed to deliver -20V required for the CD-Drive. It takes hours to search through a complicated circuit which also includes other panels to work accordingly.
Therefore, I decided to design my very own power supply and get rid of all unnecessary parts like the logic handling the battery and a complex circuit about switching the voltages for the CD-Player. Those circuits includes the parts that often fail.
Now only the parts for generating the required voltages are included. And if you look at the picture below and ask yourself why hell there is another Microcontroller included… it’s just for me to measure voltages. It can also handles two relays to switch the different voltages for the CD-Player. Alternatively there is a small logic IC which can handle the logic. In addition, the original 7805 which prepares 5V for internal logic circuits is getting extremely hot. This little fellow gets powered with 13V and has to burn 8V just for fun. I replaced the 7805 with a LM2575 and added other liner voltage regulators 7809 and 7909 to ensure to get stable 9V / -9V. This should reduce stress of components on other panels.
I tried to use new components, however, the original transformer has to be used since I haven’t found any replacement so far.
Let’s see if this design is working… it would be the first time to get a working release A š Parts are already ordered. Reckon I find some time during the upcoming holidays.
Anyway, I am not giving up making this junk stable and reliable…
btw, yes please tell me that the reset button looks into the wrong direction lol
