Just hummmm ( even if its just in your head ), then walk your hummm scale...when you get to the right note just trans that to your instrument. lol look you picked the right note on the first try Te Heeee.

Past that if you wish...just get someone to hit a note on your keyboard for you, and think the scale then pick the note. After doing that just for fun, many notes will just start to stand out to you and your dependence on "scale in your head" will get smaller.

But a side tip...pending the quality of your tape deck, the tape your playing ( and other factors ). What your hearing from the tape isn't going to be exactly in pitch ( with say solid 440/438 whatever ), its a good idea to find a song on the tape to tune your instrument to.