Dilshan R Jayakody’s Web Log

I have Panasonic DMR-E55 DVD Video Recorder and suddenly it start to get reboot when the system performs “Self Checking”. Because of this reboot problem I may not be able to record DVDs and need to put some extra effort to eject the disks. Most of the times this reboot occurs in cyclic pattern and to break this cycle I need to be eject the DVD disk manually from the system. While examine the system my primary attention moves on to the “Digital RAM card” of the system (Because it actively involves in to the DVD burning process). But after the 2 weeks of continues inspection I found that the problem is in the SMPS primary chip - STR G6535. After replacing the STR G6535, system starts to work in an order. Replacement of this chip is not a complex process but while doing that it is necessary to put some attention about the SMD components located nearby.

Logic analyzers are allowing us to monitor and /or diagnose a large number of digital signals simultaneously and these devices are essential when developing complex digital systems. In this project we design simple 8 channel USB logic analyzer with Windows version of driver software. Design of this logic analyzer is based around Future Technology Devices FT245 USB FIFO chip. With the given oscillator this system takes 14MSPS (Mega samples per second) and this system is design to work as (USB) self powered device (without any external power source). Driver part of this project is based on FTD2XX driver and GUI is developed using Delphi. Current version of driver software is design to work with Windows NT operating systems and it is highly recommended to use it with 1360 × 768 or with higher video resolutions (with aspect ratio of 16:9). This design also contains real-time logic level indicators to monitor "low frequency" signal levels and construction of that portion i...

In this project we design 8 feet C band satellite dish antenna and some of its specifications are listed in below, Diameter of the reflector : 248.0cm F/D ratio : 0.391 Focal length : 91.5cm Calculated gain (Aprox.) : 40.23 dB Materials used for reflector : Aluminum sheets and Aluminum nets Number of panels (in reflector) : 4 units Materials used for Mounting mechanism : Steel Weight (Aprox.) : 40 - 45 kg (without antenna positioning system) LNBF : Generic dual twin C band LNBF Antenna positioning system : Using D.C motorized actuator

One of my friend had Sony PlayStation 2 (SCPH-39000 series) game console and in few months back it get fail because of the internal short-circuit due to spill of some liquid over the game console. Finally he sends it to me to repair it, and I found some problems in both PSU (Power Supply Unit) and motherboard of the console. In first round of the repair I replace IC807 (78M05), PS013 fuse and all the related parts near that area (because I notice some burn marks in that location) except IC806 (NJM12904). Other than that I replace R278 (1.5k), R279 (1K + 100R), R491 to R495 (with wire links), R470 (100K), Q415 (2SC2873), Q406 (IRF7901, I got this transistor from another old PS2 game console main board, available in junk store), F001 (with some 42 S.W.G copper wire) and D404 (with 3 × 1N4148 diodes). When I replace and re-solder some of the parts as described above, I got the video signal (PS2 startup splash and main menu) from the console. But system may not produce any audio signals (i...

In this design we present an electronic number display panel using low cost and low power electronic components. This proposed design is mainly based on CD4510 - CMOS up/down counter and SN74LS47 - BCD-to-Seven-Segment Decoder/Driver. With the existing configuration, this counter may be able to count (up/down) from 00 to 99 and it can easily extend to more digits by setting up additional CD4510 and SN74LS47 chip pairs. Current system is also equipped with the beeper (which based around NE555 timer IC) to indicate the increment or decrement of the count. This system is design to work with DC 9V – 12V (500mA) power supply and at the time of testing we use 10V (2.5A) DC power source to check this system. This proposed system contain 7805 regulator and it is necessary to apply suitable heat-sink to this regulator. In this project, we design PCB using double sided PCB and make dimensions and shapes according to the existing enclosure of old electronic number panel system. It is not ...

In this article we implement virtual (computer simulation base) microcontroller driven programmable timer using Proteus VSM. This proposed system is design using Microchip PIC16F877A – 8bit microcontroller and its system software is developed using MikroC PRO 3.2 for PIC. Most of the components in this proposed design are based on Proteus VSM - simulation models and we assign standard component names to them to assist in actual prototyping. In this simulation we use PIC16F877A as main system controller and 4 row monochrome LCD display unit with HD44780 compliant controller (in 4bit mode). This proposed simulation model is design to work with +5V supply voltage, but it can also operate using battery power (3 × 1.5V). When implementing this system for the real-life use, it is highly recommended to integrate battery backup facility to this system. It helps to drive this system continuously with minimum amount of disturbances. According to the supplied source code, end user may be a...

This is a simple microcontroller base implementation to drive 2 digit 8 pin seven segment display (SSD) unit. For this implementation we use Microchip’s PIC16F84A – 8bit microcontroller unit and Proton+ PICBASIC compiler. Compared with other SSD units this SSD unit needs special algorithm to drive it. Some of the logical procedures to drive this SSD unit are illustrated in below, This illustration is valid only for single digit of target SSD unit and it can easily expand to 2 digits by activating pin no 5 and 6 with appropriate inputs. In attached design we use PIC16F84A MCU with 4 × 2SC945 general purpose NPN transistors to drive this TOD-4201LR SSD unit. This proposed system is design to work with +5V DC power supply and may not need any additional data source. Supplied software for this project is for demonstration purposes only and it perform counting from 0 to 99 and then reset back to 0. To generate the output user need to assign required number to the value variable an...