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Friday, October 25, 2019

PCB from PCBWay

    A very good solution for you to have a good PCB (board) is to place an order to PCBWay.
   First, you need to made an account on PCBWay site and after that, you can search on PCBway database.
   I order PCB for three projects:
1) AVR Atmega Fusebit Doctor (HVPP)
2) Ardutester
3) Simple VGA/Video adapter
    First project, named  AVR Atmega Fusebit Doctor (HVPP) is an old project for recovery stuck AVR microcontrollers.
   You can read more details about this project in this russian article.
   Fot this project, I received this PCBs:
    Second project project 13 arduino componen tester is based on my article named Ardutester who was wited by me a 4 years ago.
   PCB made are very nice:
   Last project is for Simple VGA/Video adapter 
witch has PCB design.
   My received boards are:

Saturday, July 20, 2019

4116 RAM tester

original article
   I needed a 4116 RAM tester for a vintage computer (ZX Sinclair Issue 2) and I search on internet.

   I find some article:
   My colegue, Dragos, made 4116 RAM tester using a schematic like that,
just he used Arduino Nano instead Arduino Uno:
   You can see their test in 4116 RAM tester with Arduino

Tuesday, June 4, 2019

Chinese Power Supply PS-1502DD (15V/2A)

original article
   I receive a cheap power supply made in China named PS-1502DD. This power supply can deliver 5 fixed stepts: 1.5V, 3.6V, 4.8V, 6.0V, 7.2V or one adjusting output from 0 to 15V at 2A (theoretically).
   After quick test with Photoframe at 4.8V and 0,63A I realise final transistor (2N3055) is put directly on steel case and is not ok.
  I remove original 2N3055 and I put 2SC5200 on aluminium radiator
   Now, I can power photoframe for long time 😁...
    Ok, I search on net informations about this power supply and I find usefull adresses:бп-кит-ps-1502dd-как-доработать-регулятор-тока/
  The schematic for this power supply is based on "old" LM723 and classical current limiter with transistor, see 

   In article you can see a god version to decrease power dissipation: use a small microcontroller to "follow" output voltage on a switching power suply instead classical transformer and bridge rectifier...