A former chief executive of S4C says the channel is wrong to "go to war" with the UK government over funding.
Geraint Stanley Jones believes S4C's board has lost "credibility and authority" in recent months.
In BBC Wales' Week In Week Out programme he calls for a government review of the S4C Authority.
But authority chairman John Walter Jones defends the decision to seek a judicial review on the announcement it would be partly funded by BBC.
Chancellor George Osborne also confirmed in the Spending Review last week that S4C's budget would be cut by 25% by 2015.
The channel was also hit earlier this year by the sudden departure of its chief executive Iona Jones.
Geraint Stanley Jones, who was S4C chief executive from 1989 to 1994, said the events of the last few months had undermined the channel's standing.
"There is a provision in the 2003 Act for the [Culture Secretary Jeremy Hunt] to instigate a review if necessary every five years and I think that should be done," he says.
"I think we need a touch of credibility and authority brought back to the board of S4C.
"We need to know the answers to certain questions which are hanging around, why things happened, and why at that particular time.
"But more importantly we need to look how they are managing the situation with regard to the future."
The programme also hears from Conservative Vale of Glamorgan MP Alun Cairns, who was was involved in negotiations by a group of Tory MPs to try to keep the channel independent.
But Mr Cairns said he had had little help from the S4C Authority.
"The authority have got us into a position where they have completely undermined the channel they're supposed to be working for and representing in their negotiations with the DCMS (Department for Culture Media and Sport).
"It is a wholly impossible situation."
But John Walter Jones has defended the channel's efforts to negotiate a good settlement, and said it did not get a fair hearing.
"We were asked to write a scenario for the future of a public service broadcaster in less than a month, which we did," he said.
"And then the decision last week meant more to other parties than S4C."
Meanwhile, Welsh language campaigners will debate a call for people to refuse to pay their licence fee from December over government plans for S4C.
At its annual conference in Aberystwyth on Saturday members of Cymdeithas yr Iaith Gymraeg [the Welsh Language Society] will claim it is the "beginning of the end for Welsh language broadcasting."
The Welsh Language Board has also described UK ministers' treatment of S4C as "deeply offensive."
But speaking in the House of Commons on Monday, Culture Secretary Jeremy Hunt said S4C's funding was now secured for four years.
He said the new partnership with the BBC would be "sustainable" and would help S4C with its recent problems of audience share.
Week in Week Out is on BBC One Wales on Tuesday, 26 October, at 2245 BST.