4538_R7100_new_filte..
Contents
1. E10 7T 80 kHz The procedure The tools apart from the usual set of screwdrivers you will need a soldering iron with a small tip and possibly a desoldering pump Note one of the small new filters circled in red ta iN Poa ha yi aL te URTE lt ALEL r 4 r itis ki bis D kS clin a i A a el gee a a i ts as Tak i A bk ay D a De he a a E a i Di a a a m a A G Y s ne i bisa lt pa S e eS a I A te te a Sa an ate ae W SA E i a y k a uke s i aa ht LA i p Tel i i be x ny al a A T ed s od i jee F Ti A y Me Unplug the speaker so you can get rid of the top cover 7 a KG Rw i Unplug the receiver Remove the top cover only unscrew 8 screws Unplug the coaxial from the converter board Remove the 4 screws that lock the REG unit then carefully move it away follow the instructions at page 33 of the instruction manual section Disassembling The filters are in the area circled in red ee Ri ase m AG unplugged L S l aI W9te8I Zoom in of the filters area The filters you want to remove are the two blue components circled in red I suggest to remove the 2 back up batteries for safety note the polarity you will loose all your memories sorry Remove the screws that block the MAIN unit then carefully tilt it upwards to do this follow the instructions at2. page 4 5 of the service manual section mechanical parts amp disassembly And install the new ones FI1 shown here for this position I used the 110 kHz filter Repeat the procedure for FI2 where I used the 80 kHz filter Remove the filters using care FI1 shown here Now that the new filters are soldered in place re assemble your receiver following your steps backwards don t forget to put the batteries back again taking extra care to the correct polarity There should be no need for calibration Please feel free to contact me if you want to exchange ideas at iz2eas arrl net Enjoy your Icom IC R7100 Michele IZ2EAS iz2eas arrl net
3. Replacing the Wide FM filters of the Icom IC R7100 by Michele D Amico IZ2EAS Introduction The Icom IC R7100 is a great receiver unfortunately if you are interested in FM DX you will find the original WFM IF filters way too wide 230 kHz What T will describe here is a simple procedure to replace the original WFM filters with narrower ones But first let me state it very clearly do it at your own risk I will accept no liability for any damage you will do to your radio to yourself or to this sector of the Universe by following the procedure outlined in this document Old and new filters The filters you want to remove are marked FI1 and FI2 in the schematic they are located on the Main Unit and they are identical SFE10 7MMH A Now the question is which filters to choose for a replacement It really depends on how crowded is the FM band on your side of the planet and what are your expectations Let s say that in principle you should use filters not wider than 110 kHz so one choice could be a couple of 110 kHz filters But I live in Italy and here the FM band is a jungle i e great fun so I decided to use a 110 kHz and a 80 kHz filter Someone suggested I could even use the couple 80 53 kHz but I decided not to go that far since I wanted to keep distortion at low levels With my choice 110 80 distortion can be hardly noticed while the selectivity is still very good I used a couple of MuRata filters marked 10 7HY 110 kHz and
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