Electronics > Repair
Aeroflex IFR-2398 / calibration / repair help
<< < (10/16) > >>
WernerFalken:
After many years of on/off work, I just completed the Backup/Restore process for the 2398 (python). As it is fairly similar, you might give the backup a shot. If the unit has its calibration data intact, I'd advise against attempting the restore (of course), but getting it backed up is important.

For the 2398, specifically, the calibration process should be trivial to workout now that the backup/restore is done. Pairing the commands with the service manual should be pretty straight forward, but I am no longer in possession of a fully working 2398... sigh.

PS Much of the seed work credit for this outcome goes to andy_silicon, btw. Without his work, I wouldn't have had to spend time doing this :) Much of the blame goes to him....lol
BravoV:
Colby, appreciate the work.  :-+

Is it possible to backup the cal data through the serial port instead of through GPIB ? As I don't own one.  :'(
WernerFalken:
If you can issue the commands and retrieve the data that way, it should be possible. The returned data is simple text/floating point data that I dump to a file. It isn't some special binary formatted file dump from the machine or anything. Issue a command, read the result, store the data. Restoring the data is similar - just commands repeated for each calibration data element.

I'd like to say that I'd try it soon, but I doubt it. I did keep my one, barely functioning unit out, so maybe some day I'll try.
tech255:
I have been reading this post with avid interest as i have a 2399b with rf problems the yig test fails in the self test routine so im just about to start having a go at repairing it, i think ive identified the white blob with 101 if you follow this link theres several on the page.

https://www.rf-microwave.com/en/transistors-rf-fet-gaas-fet/

http://www.hp.woodshot.com/hprfhelp/4_downld/products/xrs/atf10136.pdf

Ive got access to a spectrum analyzer that will get to 6ghz but no probe just wondered if i could connect it directly just to measure Whats needed with maybe capacitor or resistor in line.

Any help would be useful
Thanks


zed dez:
Hello all,

@tech255: From my previous experience with my 2395 (same as 2398 but with a frequency extender 3-26.5GHz) I'd say that YIG Fail is due to the YIG itself. It is part of a PLL and the error is triggered if unable to lock. My unit was overheated (faulty cooling fan) and inside the YIG found some gold wires disconnected (the main coil and the supply in my case). Carefuly inspect them with a microscope. When OK I can confirm the YIG will lock even when RF Synth module is opened and the only conection needed is the 10MHz reference. Also, you can check the 3.2-6.2GHz directly, it is outputed at second upper exit, counting from the IF output. A simple capacitor probe will be enough, and the LO level is very high, you can't miss it. Set the SPAN to zero.

@Colby: Many thanks for your work, helped me a lot for my 2395. It is same as 2398 (even the passwords are the same). I can confirm the GPIB link can be substituted by the RS232. Inspired by your work wrote my own calibration utility and a TRAALL? to display the trace on my laptop and play with it. The 2395 is going up to 115200. At this moment all calib data in my unit is erased, only zeroes.
Still I have 2 problems:
- For the attenuator calibs 0 to 50dBm I'll have to guess a reference for the input test signal, I don't have FCAL2398 to know how exactly is setting the RF generator during calibration steps.
- It is still unclear to me how the YIG slope is determined. I guess the offset is based on the internal test signal by tuning to 40MHZ and then gently sweeping the YIG till it gets a max level value. For the slope a second test at the other end of the band will be required, let's say 2GHz. With a single point it is assuming the GHz/volt curve is perfect linear, that is close but not perfect.
In plus, the 2395 is fitted with a frequency extension re-using the same LO (x1, x2, x4) with extra sweeps to cover the 3-6-13-26GHz bands. At it's input there is an YIG filter that must be calibrated to go in tandem with the LO YIG.
Maybe extra GPIB commands, since I don't have PSOP adapter to read the flash I'll try to boot a linux or DOS, with external keyboard pressing ESC at boot the unit is entering BIOS like a PC :)

A good new year to everyone!
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod