Having issues soldering

[Shawn Northrop]

I am trying to modify a Dr. Sampler. I am having trouble soldering to the board however, the solder does not stick to anything, it seems like the board is covered with something. when i touch two ends of 1 wire to the point i want they connect the circuit (which is what i want), however i can not get them to stay there. Any suggestions?

[R.G.]

Get the copper clean where you want to solder. It should be metallic-shining clean. Use fine sandpaper if necessary on small spots to remove grunge.

You cannot solder to dirty, oxidized, coated, or greasy copper.

[343 Salty Beans]

definitely the clean deal. Also, try tinning the wire before you solder the joint.

[BrianJ]

I really, really want to know what your doing to the DR. Sample.

[Shawn Northrop]

I was attempting to make an edrum for my sound art class, i bought a piezo buzzer a 20 sampler from radio shack and a 1/4 inch adapter. I removed the play button from the sampler (which just connected a circuit) and wired a NpN transistor to both sides of the circuit. I then wired the base of the transistor to the piezo buzzer. So basically everytime the buzzer was struck the circuit was connected and the sample played. I want to do this to the Dr. Sampler but underneath the buttons is a black surface (both sides of the circuit). If i connect them with a wire the sample plays, however i cant solder to them. I dont think its because of grease, but ill try that thanks

[Paul Perry (Frostwave)]

Shawn, you can't solder to that stuff because it is (or WAS!) conductive rubber.
Only hope is to trace some PCB traces coming away from the switch & solder to them.