Former CBC president Robert Rabinovitch and Guylaine Saucier, who served as chairwoman, are among those who signed the letter to current chairman Remi Racine.
The CBC is trying to absorb a $130-million budget shortfall due to federal cuts, declining advertising revenues and the loss of hockey rights.
The broadcaster announced last month it is slashing some 20 per cent of its workforce over the next five years, while cutting back evening newscasts and in-house production and raising the possibility of selling its flagship headquarters in Toronto.
It also signalled an intention to shift the CBC's priorities from radio and television to digital and mobile services.
Clarence LeBreton, one of the signatories, says he's concerned about diminished production capacity at the broadcaster as a result of the cuts.
Sometimes cosmetic cuts must be made to meet a budget, he says, but recent reductions amount to gutting the venerable broadcaster.
The board of directors is like the "guardian of the temple" and if somebody is dismantling it, "you should at least voice some concern," he said Tuesday in an interview.
"We think this time it's going too far."
Racine said in an email that he would discuss the letter at the next board meeting.
By 2020, CBC plans to cut 1,000 to 1,500 positions from its roster of 7,500 employees. It says that goal will in part be fulfilled by retirements and attrition and that roughly 500 of these jobs will be eliminated over the next 12 to 15 months.
The new job losses are in addition to the 657 the broadcaster announced in April.
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