I have an older model Singer Quantum, sews perfectly and I've never had a problem with it. All metal gears inside, I took the housing off and looked (after the warranty ran out.) The computer part is sealed. I bought it from HSN years ago. The machine repairman who sold Singers said he couldn't sell the model I have as it was made especially for a big sale. The model Quantum he had didn't have several of the features mine did and certainly didn't come with lots of extra accessories. And his had the synthetic made gears!