Code:
=COUNTIFS('Repairs'!$R$6:$R$5000,"<>" & "",'Repairs'!$E$6:$E$5000,"Tablet")
Btw. As COUNTIFS() and SUMIFS() work with a single condition too, I simply use only them always instead COUNTIF() and SUMIF() - so whenever I need to use several conditions instead of one, I simply can add conditions instead replacing entire function.
COUNTIF() counts entries in a range matching defined condition for single column. COUNTIFS() counts entries in a range matching defined condition(s) for single or several columns.
SUMIF() calculates SUM() of entries in single column in range matching a defined condition for another column. SUMIFS() calculates SUM() of entries in single column in range matching a defined condition(s) for single or several columns.