Here's the breakdown:
* ch - /tʃ/ (one phoneme, representing the "ch" sound)
* e - /ɛ/ (one phoneme, representing the short "e" sound)
* c - /k/ (one phoneme, representing the "k" sound)
* k - /k/ (one phoneme, representing the "k" sound)
Note: Even though the letter "c" appears twice in the spelling, it only represents one sound in the word "check."