There are fresh signs of softness in the semiconductor sector.

Pacific Crest’s Michael McConnell earlier today cut his estimates on Fairchild (FCS), ON Semi (ONNN), Taiwan Semiconductor (TSM) and Texas Instruments (TXN), while his colleague Ruben Roy, who follows specialty semi stocks, cut estimates on Atheros (ATHR) and Xilinx (XLNX).

McConnell provides a number of indications of trouble in semi land. He says checks since the Chinese New Year indicated that IC distributor resales are falling slightly below forecasts for Q1, with sequential growth declines of 5%-15%, rather than the flat to down 10% quarter that had been expected. “Distributors have cited slower-than-expected bookings from notebook ODM customers, Apple (AAPL) iPod ODMs, Korean customers and excess component inventory at Chinese handset vendors,” he wrote.

Meanwhile, he says distributors see a flat Q2; in a normal year demand would be up in the mid-to-high single digits, he says. “Expectations for weaker resales have been attributed to low visibility since the Chinese New Year, a slower macroeconomic demand environment and more-conservative build plans at end customers,” he writes.

McConnell says pricing on analog chips is “intensifying,” and that a “margin reset” is coming for the group.

Here are a few other tidbits from McConnell and and Roy:

• Acer expects overall units to decline 15%-20% sequentially in Q1, he says, with Q2 units flat to down 4%.
• Toshiba, he says, now sees a flat Q1 sequentially, versus up 5% previously.
• Notebook ODM units forecasts are for 5% growth in Q2 in aggregate, at the low end of 5%-10% seasonal growth over the past two years.
• At Taiwan Semiconductor, he says wafer shipments are forecast to track flat in Q2, “far below normal seasonality” of up mid-to-high single digits. “We believe this to be a significant development because wafer demand at TSMC server as a proxy for the fundamental health of the semiconductor industry,” he says.
• Texas Instruments, he says, has dropped prices on ints low-end LoCosto basebands to match Infineon (IFX) and Mediatek. Wafer shipments forecasts at the company’s supply-chain partners for Q2 are down double-digit percentage; normal would be up double digits.
• Fairchild, he says, has seen customer resales in Asian-Pacific; with forecasts for Q1 of mid-to-high single digit declines, rather than the flat quarter previously expected.
• ON Semi, he says, is losing share in Sony’s PS3 for power management to Renesas
• Atheros, according to Roy, is on track for Q1, but “checks indicate a slower ramp for Atheros’ Bluetooth business” than he had expected. He cut estimates for 2008 and 2009.
• Cisco, Roy says, has slowed orders to both Xilinx and Altera (ALTR). Roy says he is “increasingly cautious” about the June quarter for Xilinx.
• Broadcom, Roy says “has reduced wafer starts at its primary foundry TSMC,” shifting capacity to some other foundries for price reasons.