NFF = No-fault-found

To prevent no-fault-found (NFF) product returns and increase the success of consumer ... Minimize the cost of product support and instances of NFF returns ...
www.maskery.ca/industry/consumer.htm

利用3100手机故障查找仪可以快速方便地筛选出市场上返回来的实际上并没有故障（"No Fault Found"）的设备。此外，3100还可在移动设备（如手机）离开服务中心时提供快速功能验证， 从而保证设备返回到客户手中时工作时正常的。3100没有显示屏，利用PC ...
www.jicheng.net.cn/products/html/willtek_3100_p.html

Taiwanese terms:
非不良退回(No Fault Found; NFF). 外箱检查(Out of box audit). 市价反应(On time pricing). 价格低减( Price reduction). 过保固期之零件退回折价(Out-of-Warranty Core Credit; OOW Core. Credit). 成本低减(Cost Reduction) ...
thesis.lib.ncu.edu.tw/ETD-db/ETD-search/ getfile?urn=89431006&&filename=89431006.pdf

未发现错失, no fault found，NFF. 9513, 无归档时间, no filing time. 9514, 无初次错误, no first error. 9515, 无流动闸头, no flux gate head. 9516, 无框对齐 顺序, no frame alignment sequence. 9517, 无保护带记录, no guard band recording ...
terms.nict.gov.tw/upload/download/ download_20060222144745_62002.xls