I agree with Iku and it is ってみたかった。
The last "い" changes into かった when it is about past.
I wanted to try
やってみたかった
want to try
やってみたい!
For example;
(mi-te) 見てみたい→見てみたかった I wanted to see (it)!
(i-tte)言ってみたい→言ってみたかった I wanted to say
(ta-bete)食べてみたい→食べてみたかった I wanted to eat
[A supplementary explanation]
なかった/ない, these are denying expression which work like this:
やってみたくなかった。
I didn't want to try.
なかった means past-denial.
ない is about now, present tense.
ない/なかった work like 'No' for each of present and past tenses.
no,not,isn't,hasn't,haven't.
wasn't,didn't,hadn,t,have never.