Monthly Archives: February 2006

To start old Optrex DMC50264N LCD module you need to get +24V LCD bias voltage? Where to get it if you have only low voltage 3 … 5V? As LCD module drains very low current, it is possible to build … Continue reading →

One of the popular programs for PCB tracing and circuit diagram drawing is Eagle from Cadsoft. The software is available for Windows, Linux and Mac operating systems. Freeware version of software has some limitations: The usable board area is limited … Continue reading →

Got some bad security video cameras for recycling. Few color ones made by Philips, two Sanyo and others KC-263C and KC-383C. It is mid and high resolution black and white CCIR video cameras. Security cameras’ bodies and some generic brown … Continue reading →

Connect pulse generator from older post to your audio amplifier. Set volume to something in the middle. Connect oscilloscope to the output of the amp with dummy load. You will not see ideal square signal in the output, but all … Continue reading →

For further audio amp analyze we need square waveform generator. I can use my generator, but we can build one using very common TTL chips. We can use any 74XXXX chip which can be combined to “NOT” logic element. Most … Continue reading →

How to measure real output power of audio amplifier. Sometimes on some cheap audio devices you can see magical numbers like 1000W or something, and device is handheld. It is not real power, it is bullshit. Attach dummy load to … Continue reading →

I removed few Optrex DMC50264N LCD modules with few buttons from some old laser printers. These modules are controlled by Mitsubishi M50530-026FP and M50521FP chipset. It is 4 lines 16 symbol special LCD module controlled by master CPU only by … Continue reading →

In older post I wrote that long time ago I built my first tube amp. Today, in old magazine, I found the schematics. As I remember, the output stage was working, but I made some mistakes in pre-amp. I left … Continue reading →

For my audio amps I needed some small generator just for testing. And I also had MAX038 chip sample. Here is the abstract from datasheet: The MAX038 is a high-frequency, precision function generator producing accurate, high-frequency triangle, sawtooth, sine, square, … Continue reading →

In German (sprut.de) pages I found small schematics for caps meter. This schematic is designed for electrolytic capacitor metering. According to author, device range is from ~10µF to ~65 500 µF. This is not very accurate meter, but it is … Continue reading →