Hello, I am also repairing a very damaged IFR1200(s). I have been working on it since 2018. The things I have repaired so far are as follows.
1: replaced damaged T/R connector, I had to make a new one from parts of the original and some random junk bits.
2: The PSU unit was out of the unit in parts when I received it, despite replacing all of the parts I can find it does still not work.
3: Using an old PC power supply and an HP printer supply (for the 40 Volt rail), I managed to power up the device to find that it had the checksum error fault. replaced the battery on the CPU card, which fixed that but found the unit restarted quite often. Traced this to a low 5 Volt rail at the CPU, because the PC PSU is not easily adjusted for increased 5 Volts, I fitted a 7805 3 terminal regulator on the CPU board derived from the +12V rail. The CPU now stays up and follows commands.
4: GEN not working, traced to a track on the motherboard worn through due to vibration of the circuit cards in travels in the back of a UTE (truck) up mountains etc. 3 Other tracks also found cut through. Repaired the tracks.
5:The scope worked after repairing a bent connector pin.
6: Unit receives local FM radio stations, now.
7: There were many bulged caps throughout the unit c1 for example on the Digital Board measured 1uF where it should be 10uF. Replaced many caps on most boards.
8: Found damaged connectors on the spectrum analyzer cards from unit being dropped. This took a bit to repair as the connectors are expensive and some not available, during a troll at some hamfests/junksales I found a canadian microwave unit with the same connectors, and cables. So the damaged ones were replaced using those parts and cables.
9: I spent nearly two years trying in vain to repair the PSU unit, I finally gave up, I suspect the toroid in the main oscillator has a crack. I have replaced, all active parts more than once, after putting it back together from the collection of bits I received.
10: Needed an oscilloscope to work on the PSU, so having little $ I bought a couple at hamfests in non going condition. This wasted another year, finally got a BWD (of Australia) scope working OK, and even with that was unable to fix the PSU.
11: tripped over the PC PSU and rats nest of cables, fell down and injured myself and was out of commision for another year recovering. (Chucked the lot in a box)
12: Once recovered, tried to remember how it all went together, and where I was at. (Lots of notes, in notebooks, but after 18 months away from it it took a while to get back interested enough to get to it again).
13: Repaired more mechanical damage to the front straightened shafts of the pots that were bent, replaced the low power input connector, from another device in my junk box.
14: Opened the 150watt power resistor box to find that it was not burned out but rather corroded away especially the 10 Ohm end.
15: Regarding the RF terminator resistor, To purchase a new one was out of the question in excess of NZD 500 landed, So after much searching online for a replacement or new version thereof, I ordered a 100 Watt 10 Ohm caddock and a 100 Watt 39 Ohm Vishay resistor. RS electronics pn# 532-8561, and 810-1246. BE ADVISED they DO NOT fit in the same place. I had to file small part of one of them to fit on a diagonal with the other next to it, drill and tap new holes, move the small components around in the box and swap the 5102 and 5104 connectors on the outside of the box.
810-1246 AP101 39R J 100ppm mounted on the left, Caddock MP9100-10.0-1%10R 100W1% RS 377-8661 mounted on the right. I have pictures if anyone wants to see it. Using the left connector to take input from the T/R connector, and next connector to ATTN
16:It is now 2023 day 31 december. I intend to rebuild the PC PSU supply, (I bought a replacement unit), with the HP 30 Volt power brick 30V + 12V =40V. HP Brick 0957-2286 +30V @333mA
Wish me luck, for getting this thing going after so many years. Andrew ZL2ALW
