Stereo Audio Music Players

40 Watts Hi-Fi Music System

Stereo Music player with Tuner, 1986, LED VU meter and Analog VU meter.

SAN 20

This was done as repairing home electronics was my hobby in school days, I learnt by building Amplifiers based only on transistors from the Old Philips Circuits and Books.

Home Made Circuits

The above one is TDA2020 20 Watts Per Channel, with LED input level meter and moving-coil output meters. It would have a 5 pin din input and RCA speaker output, input for phono, tape, etc. The Speakers had a woofer, tweeter and midrange with passive crossover network.

SAN 20 Speakers

Stereo Adapter for Portable Music Player

Low Cost Stereo Adapter 20 Watts for Portable Music Player 1984, Bass Treble and Presence.

Portable Music Player

This was a TB810 based 10+10 Watts Stereo Amplifier with LM381 or 2 Preamplifier, The portable player docks in a wooden cabinet. There was no IR, Wi-Fi or Bluetooth in those days, so the device would interface with amp thru a stereo ear-phone socket-jack system with a shielded cable. Bass, treble and Presence as per an old phillps audio amp book.

Electronics Work Culture and Discipline

Systematic and Meticulous work has its own Rewards. An Engineers Notebook or a Hobby Experiments Log Book can go a long way in making a Cauliflower out of every Cabbage. (The credits of the Vegetable Analogy goes to Mark Twain)

1. Keep Work Place Clean.

Clean Tables and shelves every day before closing office, Put Cut leads and Solder shots in a separate cup to be accumulated and disposed later as these are toxic. In this cup other irritants like staple pins can be added and these can be clubbed in a month and disposed off as one metallic bulk for recycling. Never bring coffee or food to work area, Keep a waste paper basket on your side.

2. Work carefully to avoid injury

When cutting leads hold the lead in the hand and cut or it will fly all over the place. A piece like that may land on another equipment and cause shorts or it may go right into your eyes and cause blindness. Lead and Iso propyl alcohol and other Chemicals may be dangerous for health if handled carelessly. Do not use fingers, and teeth as tools it is bound to cause a injury to repent a lifetime. Be extra careful with 230V AC and more so with 440V 1 tr 2mA thru your heart and a weak streak of luck may be the last experience you ever had. Do not press your Luck too hard.

Electronics Work Culture and Discipline

3. Protect Desk or table surface.

If you are cutting something let it not leave marks on table, even adhesive stains should not deface table, use a asbestos, Bakelite, fiberglass, hardboard surface which can be disposed once in a way. Before working put two layers of news paper on the table this prevents table from getting spoilt while soldering and newspapers being hygroscopic (water absorbent) they provide a natural antistatic surface to protect CMOS Ics and are nonconductors for any Live PCB kept on the paper.

4. Use tools and equipment’s in a gentle manner.

When you use weller Iron use it as a heat transfer tool never use it for prying or crimping leads or just pressing use pliers or other tools for that.

5. Document what you do and vice versa.

Have a register in which you can make records of what you did to solve a problem or what you learnt while making an equipment this information is valuable for the company to develop production methods and also useful to your team to solve a similar problem. Share abilities and skills with fellow employees but don’t share your company’s technology and database with any other company. When you leave a company use only the abilities and skills in that broad area to evolve as a professional.

delabs notes – 80s and 90s

Booting old PC with SD Card

A Need created a concept of no Commercial Value. I was unable to revive my Pentium from the Nineties, the FDD drives have gone bad, those i am able to get from some salvage computer shops are not working. 1.2 and 1.44 both, it may be FDD controller.

SD Card boot for Old Computers

I have all the various boot floppies and software from 1990 onward and have made images also on CDROM.

If there was a SD Card interface for the Plugin Slots and an update for the Award Bios to boot from the SD card, i could get this going.

The HardDisk sizes needed are not available even in the salvage.

The External Pipeline cache also keeps popping out. The heatsink fan gone bad. But the things starts up and you can tweak only the Bios.

Solar Piezoelectric Cell

Sometime around 2008 i wrote this. It is more of Humor and less of Reality.

Vibration  Pressure are Related, Pressure is related to Temperature, Sunlight has Infra Red & Heating Ability. This should Ring some Bell.

You have Heard of Solar Cells and Panels, Sunlight to Power. Heard of Piezoelectric Energy, Vibration to Electricity

Solar Calculator

Solar – Heat – Pressure – Vibration – Electricity !! New Hybrid Solar Cell ! Someone has to just Invent it. It should Flash a few Lamps.

Micro Mech Lithography. Tiny Cantilevers, Tiny Silicone bulb of Volatile Liquid. Mini Lens Heats the bulb. Cantilever is bent a few Microns.

Pressure sensitive valve deflates Bulb suddenly, The Piezoelectric Cantilever goes Twang. The Electric Pulses charge a Supercap and battery.

The Vaporized Liquid has Condensed, it goes back to the cells by Gravity, The Shrunk Bulb draws the liquid. Ready for next Cycle.

If it works, credit me, else all credits go to Tweedledum and Tweedledee.
Once upon a Time – ┬áby delabs