R&S SMIQ06B - Low Output Power

[energy_hunter]

I was using my SMIQ06B at +8dBm, 915MHz when the output power dropped to -12dBm. When set to 0dBm (no offset) the output power ranged from -20dBm to -16dBm over the course of 15mins.  Has anyone seen this problem?  I'll review the other SMIQ06B repair threads that look awesome in this forum.  Seems like the final amplifier failed or it may be an attenuator is stuck in a high state.  Thanks in advance for any advice.

[DaJMasta]

If it's not present in the higher frequency bands (above 3.something GHz), then it's probably one of the stages on the 3GHz board - and if it's localized to one area on the 3GHz board, it could be localized to one of the filter paths.  Does it show as output unleveled while the error is showing?


If the power is varying slowly, or in an analog manner, it's not going to be the mechanical attenuator.  That can still leave the electronic attenuators, but those should be in the ALC loop, so the output should show as unleveled if that's the case.