What was the problem with using valves in computars?

The main problems with using valves in computars were:

* Size and weight: Vacuum tubes were large and heavy, which made them difficult to use in compact computers.

* Power consumption: Vacuum tubes consumed a lot of power, which made them inefficient and expensive to operate.

* Heat production: Vacuum tubes generated a lot of heat, which could damage other components in the computer.

* Reliability: Vacuum tubes were not very reliable and often failed, which made it difficult to maintain computers.

These problems were largely solved with the development of transistors, which were smaller, more efficient, and more reliable than vacuum tubes.