4 replies to this topic

[thomas3120]

Hello,
Was looking around my 2600 Jr. mainboard and was wondering what the component(s) 'W2', 'W3' are. I tried looking at the schematics, etc... but couldn't find anything.
They look like resistors, beige in color but with only one black band around the middle.

t

[jaybird3rd]

They're "zero-ohm resistors". As I understand it, these are basically ordinary pieces of wire that have been packaged as resistors so they could be installed by pick and place machines during manufacturing.

[thomas3120]

Ahh, thanks JayBird ..basically just jumpers...

t

[Stephen Moss]

Not exactly, a jumper usually refers two or more pins in a row, two of which are shorted by a shorting link which depending on its position determins the how the equiment functions thus allowing a single PCB design to do several things, for example setting its video mode to PAL or NTSC.
Zero Ohm links are usually used to as a way of continuing a PCB track the has to pass over others predominately (but not always) used on single single PCBs, as JayBird said it allows automated construction of the PCB as opposed to people manually cutting, bending and soldering sections of wire in place.

Edited by Stephen Moss, Tue Aug 23, 2011 5:01 AM.

[thomas3120]

Stephen Moss, on Tue Aug 23, 2011 5:00 AM, said:

Not exactly, a jumper usually refers two or more pins in a row, two of which are shorted by a shorting link which depending on its position determins the how the equiment functions thus allowing a single PCB design to do several things, for example setting its video mode to PAL or NTSC.
Zero Ohm links are usually used to as a way of continuing a PCB track the has to pass over others predominately (but not always) used on single single PCBs, as JayBird said it allows automated construction of the PCB as opposed to people manually cutting, bending and soldering sections of wire in place.

Thanks for the info So basically it's a 'continuation' of a trace b/c of other traces passing by, etc..? Maybe because of some design change or another limitation of a single or double sided PCB?