Can anyone give me a guess as to what this component is ? It doesn't have any markings on it. Any way to determine the values if it's a capacitor or resistor ? Thanks.

 

Looks like a semi with blanked out part No.
Or could be a a OEM part.
What is the board notation?
Max.

 

There is no board notation. It has 6 legs and only 4 are hooked up. Thanks.

 

Some optocouplers are in white enclosure.

But to get further, we need to see pictures both directly from above and from the solder side.

 

Here are photo's sorry for the quality.

 

Generally in these circumstances it is very difficult without doing a little reverse-engineering on the relation with other components and parts of the circuit to get a feel for what the component actually is.
I concur that many 6 pin IC's in white are opto couplers as in Fairchild examples.
Max.

 

Here are photo's sorry for the quality.

Useless.
Like Max said, tracing out the circuit will tell you what it is, if you're good at this.

 

Get some rubbing alcohol and wipe off the black cover. You might find the marking underneath.

 

I was just trying to get an idea of what type of component it was so I could evaluate it in context of the circuit. two of the legs are not connected and two are tied to ground. One goes through a capacitor to pin 2 of a 555 timer. The other goes through a resistor to a wire. I know this probably doesn't help much, but looking at whatever was suggested will help me. I was thinking it might be a opto.

 

Get some rubbing alcohol and wipe off the black cover. You might find the marking underneath.

I'll try that.

 

If it is in the power supply circuit (big capacitor(s), transformers/chokes, and rectifiers) there is a good chance it is an optical isolator. If it is, I am unimpressed with the creepage distance.