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Category Archives: electronics

Oscilloscope calibration, what a pain

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Filed under electronics, Hardware
Tagged as , , ,

Awhile back, I had recieved an oscilloscope from someone. a Conar model 255 solid state oscilloscope. 

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It worked ok but I couldnt trust the readings from it or even the voltages it displayed. I could get basic wave forms displayed and thats all I really needed it for. As time went on it started acting up. Certain setings would not display, simple sqaure waves had major overshoot …… I could go on with so many of the issues that started to appear. So today I sat down and did the calibration from the manual. What a pain.

total time spent on it was about an hour and I did the best I could.
I still need need to buy 2x LM733 and a 741 or a better drop in replacement, also a few capacitors and transistors. But those will have to wait till I am employed again.

here are a few pics of the internals

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VS 2121 Autopsy

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Filed under audio, electronics, General

I was given an Altec Lansing VS2121 powered speaker sytem that was going bad. And I wanted to recycle some of the parts out of it. What I found inside was quite interesting.

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Here is what I found,
2 x lm324 quad op amp from st
2 x tfa9842j single chip 2 channel amp
and a whole bunch of passive through hole parts (caps, resistors) .
It is a very simple design. Now I have some decent op amps and a decent size transformer (120v to 15.3v 1.6A) with a nice particle board box.

Time to start thinking of what I can remake this into.
Happy Hacking!

Experiments in Home Audio (lm386)

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Filed under audio, electronics, General, Hardware
Tagged as , ,

I really needed a quick amplifier to power a few book shelf speakers. Looking around my ic bin, I found a few lm386s.
Next I pulled the rest of the parts (1x perf board,  2x ic sockets,  2x 100uf caps, 2x 5k pots,  some wires,  and a few odds and ends) 

Put all this in a blender, bake for few hours and this is what you get.

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The results are,  its not  a bad sound. some noticeable distortion at higher levels. More improvements can be made, like changing the output caps to bigger ones,  adding a gain selector….etc.
But what I have now works. Next a class A amp and other projects.

Almost Time to Test.

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Filed under electronics, Hardware

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Most of the motor wiring done. tomorrow I will test the motors and to make sure there are no shorts or other issues.

WP mobile app test & update

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Filed under electronics, General, Hardware, MSP430

Hopefully this will help me stay motivated to keep posting. my current side project

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My motor driver should be done this weekend. 

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