E4418A/B CLIP和测量板怎么升级

我有几年前购买的E4419A功率计，直到现在只用于8487传感器，问题是如果我将E4413A传感器连接到通道A并降低功率从+10到-60dBm，一切都看起来很棒直到你
达到-30dBm标记，如果你降低，电表上的电平读数会下降到-70dBm并保持在那里，一旦你回到-30dBm再次读数就可以了，这个问题不会出现在B频道上
测量板！
我正在寻找这个单元的原理图，看看我是否能找到问题，但如果有人对板上的问题有任何建议，那么id很感激，也有人有原理手册的＃部分吗？
第二个问题是关于测量板上的EPROM，几年前有一个升级套件可以使用E9300系列传感器，但它现在已经过时了，有没有这个EPROM的immage或hex文件可用或者
有人有可以复制的EPROM吗？



     以下为原文

  i have a E4419A powermeter i bought a few years ago and up until now only used with 8487 sensors , the issue is that if i connect a E4413A sensor to channel A and step down power from +10 to -60dBm everything looks great up until you hit the -30dBm mark , if you go lower the level reading on the meter jumps down to -70dBm and stay there, as soon as you go back to -30dBm the reading is ok again , this problem does not appear on Channel B and follows the measurement board !
I was looking for the schematics on this unit to see if i can find the issue but if somebody has any suggestions on what the issue might be on the board then id appreciate it , also does anyone have the part# for the schematic manual ?

Second question is in regards to the EPROM on the measurement board, there was a upgrade kit available a few years ago to enable to use of E9300 Series sensors but it is now obsolete , is there a immage or hex file for this EPROM available somewhere or does anyone have a EPROM that can be copied ?