By Jeffry Bartash Chip makers and related companies led technology stocks Monday, and managed to hold onto early morning gains, after a market updraft had carried the entire sector higher. Advanced Micro Devices Inc. (AMD) gained 2% and Micron Technology (MU) shares rose 1.7%. Shares of chip-software maker KLA-Tencor Corp. (KLAC), however, led the tech stocks in the S&P 500 Index (SPX) with a 4% gain. Not all companies held onto their early morning gains. EBay Inc. (EBAY) shares slipped into the red after being up nearly 2%. Similarly, shares of Apple Inc. (AAPL) and Cisco Systems Inc. (CSCO) retreated to modest gains after being up more than 1% earlier in the day. Shares of International Business Machines Inc. (IBM) and Qualcomm Inc. (QCOM) were up slightly after retreating from gains of more than 1%. The tech-heavy Nasdaq Composite Index (RIXF) was up about 0.2% at 2,313 points. Similarly, the Philadelphia Semiconductor Index (SOX) moved up 0.6% to 373.5 points, while the Morgan Stanley High Tech 35 Index (MSH) struggled to stay above water. Earnings reports begin trickling in for the tech sector this week. Software developer Adobe Systems Inc. (ADBE) on Tuesday will deliver second-quarter results to kick things off. On Thursday, Oracle Corp. (ORCL) will give its fiscal fourth-quarter report, while Research In Motion Ltd. (RIMM) is set to report first-quarter results. Apple will also get lots of attention on Thursday to mark the first day of sales for the new iPhone 4. In just one day last week, Apple said it had taken more than 600,000 preorders for the smart phone.