Weird noise from crack [solved]

[yun]

Hi, all.

I have some weird noise from my crack. When I turn it on, it is dead silent, but after 20~30 seconds, it starts make some noise, and it sounds like mixed of static noise and squeezing Styrofoam. 
I checked if it is any connection or assembly issue, but no luck. (It happens regardless input cables are connected or not, even without tubes)

Maybe, I will try reflow or re-soldering the headphone jack part, but is there any other recommendation that I can try?

Looking for your advices, and thanks in advance.

[Paul Birkeland]

Plug in some inexpensive headphones and poke around the circuit with a wooden chopstick.  If you can find a spot that changes the noise when you poke it, that can help to focus your efforts.  Also triple check that the two black wires on the headphone jack are well captured by solder.

[Doc B.]

You might try cleaning the tube pins as well.

[yun]

Thank you all. After re-soldering a couple of joints at headphone jack, it looks the noise is gone.
It reminds me always the basic is the most important.

Thank you all!