Zero ohm resistors?

[BigSteve]

Is there any purpose to the zero ohm resistors other than manufacturing convenience?

I have an STFM board (C070789 Rev D) that I want to fit the HD (floppy) board and the row of resistors that appear to be 'links' (L5 to L11) to the parallel port) are interfering.

Can I simply replace these with links ensuring they don't short to the ground trace below? I note that 'L' for component shorthand often indicated an inductor. Does this apply to Atari?

TIA

[stephen_usher]

Yes, you can just replace them with header pins and a jumper.

[exxos]

They used to be RF filters in a 3 pin package. Atari used zero ohm resistors on later machines. You can wire link them instead just be careful not to short to the center pin as its gnd .

[sporniket]

Can I simply replace these with links ensuring they don't short to the ground trace below? I note that 'L' for component shorthand often indicated an inductor. Does this apply to Atari?

"Lxxx" just before an external port ought to be "T filters", an "EMI LCL Filter", at least, this is mentionned on the STe schematics.

T_filter_mention_ste_original.png

On my conversion into Kicad, I used the dedicated symbol :

T_filter_kicad.png

[BigSteve]

Awesome - that makes life easy - thanks for quick response to all who replied. This looks to be a great forum!

:D

[Maximilian]

In some cases I have seen a 0 ohm resistor being used as a sort of fuse, and in those cases I have seen these fail.

But seeing the previous responces it is not likely in an Atari.

[terriblefire]

A 0 ohm resistor can also be used to add a pseduo extra layer for those one or two signals you need to route over each other. Used mostly on single sided PCBs etc.

[rubber_jonnie]

Atari do tend to use links or zero ohm resistors in a few places. Look at the STE board for example. The TOS ROM Jumpers, W102, W103 & W104.

These are usually linked with the same zero ohm resistors.

As long as you're sure any replacement doesn't cause a short, a simple wire link is just the same, at least in the case of the ST.