A range of manufacturing issues led to a shortfall in iPad shipments in Q1, according to a . Market researcher IHS iSuppli has cut its iPad forecast for the year by about almost 10%.

FIRST LOOK:

Reporting its this week, Apple said it sold 4.7 million iPads during that period. "The sales were lighter than expected, a sentiment echoed by Apple executives who expressed frustration the company didn't produce enough devices to meet demand," according to Dow Jones.

IHS iSuppli originally forecast iPad sales of 43.7 million for all models in 2011. It's now dropped that to 39.7 million. That's because, the research firm says, Apple ran into problems with the quality of liquid crystal display panels, and shortages for the speaker in the iPad 2 tablet computer.

These problems were not related to the March earthquake and tidal wave, according to IHS iSuppli. But the research firm says Apple could face later this year quake-related supply issues that would prevent it from boosting iPad production.