SMIQ6L - wrong freq. at output - [SOLVED]

[piotrekjan]

Hi All,

I've killed accidentially my SMIQ6L. Not sure how I've done it, as I've removed covers and front display module and then installed these back, but now unfortunatelly seems to be damaged. Also made some check inside display module but I hope not killed by ESD.
The issue is that it stopped provide proper frequency. As this, does not have display it is pretty difficult to guess what failed.
In general my observation is that when I set 10MHz it sets 660MHz, if I set 50 MHz it sets 700 MHz.
The level change works correctly.
My first doubt would be that there is missing signal at some mixer but I'm not specialist in repairing such equipment and do not have even idea where start searching in what module...
I would appreciate some suggestions how to start with this repair.

[piotrekjan]

Had anyone chance to talk via RS-232 with this generator ? I'm able to send commands, like turn off/on RF but not able to get response...
I'm wondering if possible to get diagnostics over RS-232 maybe this would be some starting point ?

Regards,

[piotrekjan]

By connecting via GPIB I was able to read status.

The error I have is 211 - "Summing loop unlocked"

I've also tried command :DIAG:MEAS:POINT2? - instrument return 0.5310 in programming manual is 3.52 - however no idea yet where point 2 is.
Below the values from :DIAG:MEAS:POINTx? commands:
1 - 0.001904
2 - 0.5310
3 - 0.001563
4 - 0.000732
5 - 0.0458
6 - 5.0098
7 - 3.3286
8 - 8.0000
9 - 9.0000
10 - 10.0000

Starting from 8 the readout is just number of measurement point - so values from 8 up are not idicative anymore.

[Update]
Only calibration was necessary. After doing it via GPIB it everything came back to normal operation.

[mcckevin]

Hi Piotrekjan -- I too am getting error 211 - "Summing loop unlocked" after replacing the output fet on my SMIQ03B Signal Generator. This error wasn't present before I fixed the FET. I tried all the calibrations I can find from the front panel yet the error 211 persists. Can I ask you to expand a little on you comment

"[Update] Only calibration was necessary. After doing it via GPIB it everything came back to normal operation."

What commands did you send over the GPIB bus to fix the error 211? Thanks.
Kevin

[piotrekjan]

Sorry for late answer but I do not visit this forum too often.

The GPIB sequence to fix it is following:

*RST;*CLS
:SYST:PROT1:STAT OFF, 123456
:CAL:VSUM?
:CAL:ALL?
:SYST:ERR?