Top octave divider chips

[ionsager at sn.no]

I need some MM5824. Keyboard Systems have them at $18. Is that the
going rate for these chips? 
They are used in the Korg PS series and seems to have a high failure
rate. 6 were blown in the PS I'm repairing.
I have similar experience with the MM5823 used in the PolyMoog. 
Is it just bad luck or are these chips prone to failure?
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Ingar.				               Norway