Samsung's official investigation into the cause of widespread faults with the Galaxy Note 7 will blame "irregularly sized" batteries and manufacturing faults, according to a report from The Wall Street Journal. The company is set to announce the results of its inquiry this weekend, but the WSJ claims to have revealed its conclusions early, citing information from "people familiar with the matter." From the report: The WSJ says Samsung hired three independent "quality-control and supply-chain analysis firms" to conduct its investigation, with these firms concluding that two separate faults affected the Note 7. The first fault relates to devices that used batteries made by Samsung subsidiary Samsung SDI. These batteries didn't fit inside the phone properly, which led to overheating and, in some cases, explosions. When reports of the Note 7 fault first emerged last August, executives initially believed the problem was confined to these particular devices. In response, they increased production of the Note 7 using batteries made by Hong Kong-based firm Amperex Technology. According to the official investigation, this rush to ensure there was an adequate supply of Note 7 devices for the market led to the second fault -- with the increased pressure on production creating unknown "manufacturing issues."