Scavenging parts, a good idea?

Parts Questions
1

Hi!

I’m preparing stuff to build my first midibox+ and I was wondering what you guys think about scavenging old resistors, leds, switches, pots and capacitors from old motherboards, amps and the like…

Can some1 provide me with a link on how to read capacitors and resistor values as well?

TIA!

2

Hi

Resistors: probably not worth it as they are very cheap!

Caps: your better off with new ones as they can be difficult to test

Pots: yeah 2nd hand is good

Switches: yip good

Leds: no problem there either

Sorry I dont have a resistor value chart handy but they should be easy to find?

LO

3

Not that I use it, I measure. But here a resistor chart:

http://members.tripod.com/~schematics/resistor.htm

happy scavenging!!

js

4

Hey

Normal resistor (5-10%) have 4 color rings.

Ring 1, Ring 2, Ring 3 and Ring 4.

One of then will be gold or silver.

Place the resistor with that one to the right, Its ring 4.

Take the number of ring 1 (from the color code below), write it on a paper.

Take the number of ring 2, and write it to the right of first number.

Place the number of zero’s from ring 3 coler code and place it to the right of the 2 number.

Thats you resistor value in ohm.

Remove 3 zero’s and its in Kohm or remove 6 zero’s and its in Mohm.

Color code:

Color____Number__Number of zero’s

Black______0________non

Brown_____1________0  ( 1 )

Red_______2________00 ( 2 )

Orange____3________000 ( 3 )

Yellow_____4________0000 ( 4 )

Green _____5________00000 ( 5 )

Blue_______6________000000 ( 6 )

Violet______7________0000000 ( 7 )

Grey_______8________00000000 ( 8 )

White______9________000000000 ( 9 )

Like this

Resistor   Brown, Green, Red, Gold

Value               1,          5,     00            =1500Ohm or 1.5Kohm

Try for your self:

Green,Blue,Yellow,Silver=?

Yellow,Violet,Brown,Gold=?

Gold,Green,Red,Red=?

Orange,White,Black,Gold=?

Hope this helps

Kent

5

Heya!

Check out http://www.coinoptech.com/tech/res.html

More fun than a table when you are digging through the parts bin for a resistor… :wink:

Smash

6

I built my midi > sync  < midi converter with scavenged parts. Only the chips were new.

If you are careful you can get stuff off boards and use it. :wink:

I don’t have a resistor chart. I tell LO the colours and he tells me what they are :wink: :wink: :wink:

ian

7

Thanks a lot for all those replies! I suppose values are written on capacitors? I also have a multimeter that allows me to test caps although I am not to sure how it works…

Doing MrM little test:`

Green,Blue,Yellow,Silver=560 KOmhs

Yellow,Violet,Brown,Gold=470 Omhs

Gold,Green,Red,Red=2.2 MOmhs

Orange,White,Black,Gold=39 Omhs

Thanks smash for the neat app too :slight_smile: (I didn’t use it to solve the test though hehe)

Thanks every1

8

The cap measuring is normally done with frequency tests. A certain frequency goes in, the cap is pulled down to ground with a resistor and voila, you have a low pass filter. The capacity is then just measured by the loose of voltage.

For scavenging: I really do think that its only worth it for a little more expensive parts. I did scavenge stuff also, but:

Resistors, LEDs, diodes and transistors are so cheap that ordering them is just much less work.

Pots, switches and so on are worth being scavenged, cause theyre just more expensive.

Be carefull with scavenging caps. Especially electrolytic caps. First, they get melted very easily, and second, if they were not used for a long time (about 5 or more years) it *can* (although really seldom) happen, that they blow up although you have putted them in with the rigth polarity.

Hope I could help you.

9

Oh yes im very wise when it comes to electronics: :-/

where there is a

#1 I colour in red

#2 I colour blue

I think they call it “paint by colour”

10

Hey Xcen

Good job on my test. I did not get you on the reverse one, Nice :smiley:

Kent