るだけ～てみるTry as much as one can
This pattern says that someone will at least try an action to the extent they can, even though success is uncertain. It often expresses determination without suggesting confidence about the result.
How the pattern works
The part before だけ sets the available limit: what can be done, or at least what is worth attempting. The part after it repeats the same action and adds てみる, which presents the action as a trial. The surrounding context normally explains why the result is uncertain.
Trying up to the available limit
成功するかは分からないが、手がかりを探せるだけ探してみる。
I do not know whether it will work, but I will try searching for as many clues as I can.
AnalyzeThe potential form sets the maximum attainable extent, while the repeated verb names the action actually attempted.
Common forms in use
The ending can be polite or volitional without changing the central meaning.
More than simply trying
てみる by itself simply presents an action as a trial. The repeated pattern with だけ adds an extent or minimum-effort idea: try as much as possible, or at least make the attempt despite doubt.
初めての料理だが、作ってみる。
It is a dish I have never made before, but I will try making it.
AnalyzeThis is the basic trial form; it does not state that the person will do as much as possible.
More examples
この案が通る可能性は低いが、説明するだけ説明してみる。
This proposal is unlikely to be accepted, but I will at least try explaining it.
Analyze資料が十分ではないが、確認できるだけ確認してみます。
The materials are insufficient, but I will try to check as much as I can.
Analyze一度しか会えないので、聞けるだけ聞いてみよう。
There will only be one chance to meet, so I will try asking as much as I can.
Analyze勝てる自信はない。それでも、やれるだけやってみる。
I am not confident that I can win. Even so, I will try to do everything I can.
Analyze連絡がつくか分からないが、電話するだけ電話してみた。
I did not know whether I would get through, but I at least tried calling.
Analyze古い記録なので見つからないかもしれないが、探せるだけ探してみます。
Because it is an old record, it may not be found, but I will try searching as thoroughly as I can.
Analyze