Electronics > Repair
Aeroflex IFR-2398 / calibration / repair help
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George Edmonds:
H

Reoly #54 in this posting.

G Edmondsi
EB4CUV:
Hi George,

Sorry for the inconvenience. In that post #54 the attached .pdf is from the rceiver front-end board and I don't see any other archive.
The schematic that I need is of the input board where the N connector is and not for the front-end because the diodes are burned.

Thanks,
Julio
George Edmonds:
Hi Julio

Having now had a little time to look at your photograph I would be very surprised if this is the only damage.

At present I cannot provide a schematic of the input assembly, but you do not need one, just a little information.  The only RF path components are C1, DC blocking capacitor which is a 1uf at 25V device and the two catcher diodes CR1 and CR2, these diodes are MSMP-3892, data sheet attached.

All the rest of the input assembly is providing a plus and minus reference supply derived from the main instruments + and – 15VDC supply.  CR3 and CR4 are MMBZ5232LT1 Zener diodes.

Regrettably I suspect that there will be further downstream damage, particularly to the solid state switches.

Hope this helps

G Edmonds G6HIG
EB4CUV:
Hi George,

Thanks for your help George. People like you make life easier for others.

I've removed the bad diodes from the input board, leaving just the capacitor until a replacement arrives.

Your suspicions are true. The first solid state switch on the front end board is damaged.
I have done what vk2cow said in post #56, remove the first AH002R2 switch and bridge pins 1 and 7.

Now, I inject a 40Mhz and -30db input signal into the N connector and the device passes all the tests correctly.
I'm on the right track.

By injecting other signals, the device measures almost correctly. The next step is to do a good calibration.

The next question is: where can I find the calibration software or some other that can handle the device?

Again, thank you very much for your time and help. I hope my experience is useful to others as well.

Julio, EB4CUV
Ron Castle:
Hi George,

Ours is working but the center of the screen is all washed out. I guess I can use the video out would you know what the display P# might be.
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