T. Ment wrote:
On Wed, 26 Jun 2019 16:25:17 -0400, Paul wrote:

It's too bad you didn't mention the Ebay item, to see
if there was any semblance of a specification for it.

https://www.ebay.com/itm/382885459517

They say:


Max. Forward Current: 20mA

- For red ,yellow ,green it is 2V , 20mA ,forward voltage is 2-2.2V


Maybe I'm overvolting it. I think that motherboard pin had 5v. But I'm
not sure. I need to open the case and check it again. I'll get back to
you later on that.

Obiwan, use the maths.

Plug in the 2.2V instead of the 1.6V in my example.

Select a current flow, less than 20mA, like 4mA, and
work out the 1/4W resistor to use.

5V - 2.2V 2.8V
----------- = Rseries_ohms = ------ = 700 ohms
0.004 amps 0.004A

If there is 180 ohms already on the motherboard, we need
another 520 ohms. Look in the assortment pack I showed,
for the nearest higher value compared to our calc
value of 700 minus the 180 already on the motherboard.

"Increasing resistance = Less light"

*You can only hurt the LED, if you plug direct to +5V*

With some resistance in the circuit, and not exceeding
the PIV if you were to plug it in backwards, you're
made in the shade.

____ new-Rseries _____
\ /\ / +
x x LED
/ \/ \______________________ -

twisted
pair
harness

The resistor needs to be series-connected to limit
the current flow and reduce LED intensity.

Paul