8753A衰减器怎么了？

您可以运行多个测试。
如果它锁相任何部分，则意味着功率放大器的信号源可能正常。
8753A没有衰减器。
您应该运行源预处理服务测试，然后运行源锁相服务测试。
首先，您必须在8753A CPU板上移动跳线，以便将服务测试结果写入闪存。
造成故障的一个可能原因是腔振荡器（3.8 GHz固定振荡器）的漂移，不允许低频锁相。
如果它漂移得太远，则预调功能无法找到正确的信号。
在这个论坛搜索8753来源，你会发现很多关于服务来源的帖子。



     以下为原文

  There are several tests that you can run.  If it phase locks over any portion, it means the source is likely OK for power amplifiers.

There is no attenuator in the 8753A. 

You should run the source pretune service test and then the source phase-lock service test. First you must move a jumper on the 8753A CPU board to allow the service test results to be written to the flash memory.  

A likely cause of trouble is drift in the cavity oscillator (3.8 GHz fixed oscillator) that doesn't allow the low frequency phase lock.  If it has drifted too far, then the pretune function can't find the right signal.  Search this forum for 8753 source and you will find many posts on servicing the source.

谢谢joel博士，我已经做到了。
测试46：模拟总线常通测试45：通过默认预调校正常数测试48：默认校正常数失败（即使我增加功率电平）现在我在所有频率上都有一个假锁定消息我已发布的跟踪对应于
服务手册中的源组图3。
而且与BTW服务手册相比看起来相当糟糕，我似乎无法修改poxer级别，即使在高频率下我已经使用模拟总线使用A而不是R Yig更改采样器似乎相当不错我已阅读此论坛你能不能
请给我下一步？
巴斯蒂安



     以下为原文

  Thanks dr joel, 

I have already done this. 

test 46: analog bus constant pass
test 45: pass default pretune correction constant
test 48: default correction constant fail (even if I increase the power level)

Now I have a false lock message on all the frequency

The trace I already post is corresponding to figure 3 of source group on service manual. And it seems pretty bad compared to the service manual

BTW, I seems I could not modify the poxer level even at high frequency

I have changed the sampler using A instead of R 

Yig current using analog bus seems pretty ok

I have read this forum

Could you please give me next step ?
Bastien

拔出光源，测试腔振荡器。
应该具有3.8 GHz + -10 MHz，大约+8到+12 dBm;
如果关闭超过约30 MHz，则无法锁定。
如果您没有源扩展板，则可能需要单独取消挂钩和偏置。



     以下为原文

  pull out the source, and test the cavity oscillator.  Should have 3.8 GHz +-10 MHz at about +8 to +12 dBm; if it is off by more than about 30 MHz, it can't lock.  You might need to unhook and bias it separately, if you don't have a source extender board.