Upon close inspection of an Arduino Uno, it doesn't appear that Pin 13 is connected to a 1k. There is a trace that runs to the part labeled "102" below the L smd LED which goes to that LED. So is pin 13 connected to a resistor or not? If so where is it?
There is a trace that runs to the part labeled "102" below
102 = 10 with 2 zeros = 1000 ohms = 1kOhms
OLD arduinos had a 1k resistor connected between the AVR pin and "pin 13", enabling you to plug an LED directly into the connector.
Newer Arduinos (starting with or before diecimila) have a direct connection between the AVR and pin13, but added an on-board LED with its own resistor.
You can still find tutorials on the net that say that pin13 has a resistor an can therefore be directly connected to external LEDs, but those are outdated and incorrect; 99% of the Arduinos you come across will be newer than that.
Pin 13... along with 12, 11, and 10 ALSO connect to the ICSP circuits and off board connector.
And the software pulses pin 13 high briefly BEFORE your "setup()" subroutine executes....
Ah, the fun we have when we look into the details... sigh.