Batboard

All:

I'm currently working on an IFR 1200S that belongs to a museum ship our communications group is associated with. We found it on the floor under a bench in the electronics lab along with a Rohde & Schwarz signal generator (next thing to work on). Both were sitting in a bit of water due to a small leak after the winter. Needless to say, nothing is on the floor there anymore and we think we have the leak fixed.

I have the 1200S working pretty well now except for the spectrum analyzer. I did find a switch problem that was causing the baseline to drop well below the bottom of the display, but I'm having some issues now doing an alignment on the Spectrum Analyzer display. I'm not able to get it to hit all the right levels for -40, -70, -90, and -30 with the same settings. I'm wondering if I should just start over with a full alignment of the unit, which I haven't done yet.

Second, it's showing firmware version 1.4. Is there any reason to upgrade the firmware and if so is newer firmware available? I do have a PROM programmer, so can take a file.

Thanks,

Chuck

Well, I'd hope nobody just gives you "a file" of the firmware, as that is a copyrighted work. You can contact Aeroflex Service and see if the firmware is up to date (I'll ask around at work tomorrow and see what I can find out, but the most assured way to find out would be talk to service).

I'd suggest a full cal if you have the equipment to do it. You might also have a dirty attenuator.

Makes sense about the firmware rights. I'll get with Aeroflex about that.

Actually, the attenuator is in pretty good condition and I was checking a number of other things on it yesterday evening and most everything is spot-on. The only known issue at this time is the spectrum analyzer calibration. As a matter of practicality I could even live with that if I had to, but it would keep bugging me every time I looked at it.

Guess I'll set aside some time to do the full cal.

Thanks

If you want a full alignment, you can try Kurt at KG Electronics. We have sent units to him in the past and were happy with his work and his prices.

http://www.kgelectronics.com/

As mentioned before would go through the whole 1200 calibration in order.

That way you have a solid base ...would use the high loop adjustment procedure on the KG electronics website ...much more direct method of doing the alignments.

The spectrum analyzer adjustments have quite a bit of interaction so it can take a couple of passes on some of the sets to get them close.
At the very least start at the beginning of the 1200S scope calibration. It takes a few minutes and needs a good external signal generator ( that could be your issue as well if the signal gen used has some output level conditions ...may want to verify on another SA )


PS the output attenuator has nothing to do with the Spectrum analyzer and there is no input attenuator on the 1200 as well,

I didn't mention that the spectrum analyzer is also off frequency by -7KHz. If I am looking at a signal at a given frequency, the indicated signal on the spectrum analyzer is 7KHz to the left of zero. If I tune the IFR to 7KHz below the desired receive frequency, the signal on the spectrum analyzer moves to the zero point.

Sorry folks. Please ignore that last message. I posted it in the wrong thread.