Modifications for the ICOM - RogerK

19-07-1998(IC-W2A) IC-W2A signal levelHere is more info on the the performance of the W2A after the mod.Well folks I have had my IC-W2A for one week now & am,needless to say suitably impressed. But now my comments...Why did Icom have to change the DC input socket to what the W2A has. It is very unusual & as far as I can find out, Icom arethe only people who can supply a plug for it. I think they should have stayed with the more common 2.1mm DC jack as per theIC-32AT.I did some checks of the receivers using an IFR 500A signal generator & the following is what signal level I needed to get 1 "S"point on the W2A's S meters.70MHz, 1mV (milli-volts) 80MHz 0.5mV 90MHz 0.25mV 100MHz 75µV (micro-volts) 110MHz 1.5µV From here to 170MHz lessthan 0.2µV 173MHz 1.5µV 174MHz 75µV 200MHz 75µV 250MHz 0.5mV (whats going on here???) 275MHz 4µV 300MHz 1.5µV320MHz 5µV (changed to UHF main VFO from here on) 400 - 450MHz less than 0.35µV 460MHz 0.75µV 465 - 510MHz less than1µV 520 - 690MHz less than 2µV 700 - 999MHz varies from 7.5µV to 2µV, dips to 0.35µV at 900MHz. Quite impressive, but Iwould really like to get better sensitivity at the 70 - 80mhz end. Studying the circuit diagram shows bandpass/bandstop filters allover the show, so maybe its possible to modify a few to increase sensitivity here.I am gathering together the ciruits of the Icom IC-R1, IC-24AT & W2A to compare the front ends so we will see what comes ofthis experiment in the near future.One other worry was the on/off switch, how do you turn the set off when the battery is flat. I am concerned about running thebattery to zero volts, hopefully this does not occur. I have been disconnecting the battery when charging to prevent anythingfunny happening.The antenna supplied with my W2A is an FA-1443BB, whats the difference between this & the FA-1443B, & the FA-4B suppliedwith an IC-R1.One more gripe, I dont like the plastic plug/covers over the DC jack, headphone, external speaker sockets, they should havebeen rubber as per the IC-32AT, as I can see already that they will not last very long after prolonged use. Boy what a moaner,you say, small complaints but this would really have made it the best. I wonder what Yaesu & Kenwood are going to do tocompete with this?This modification is read 959 times.top of page19-07-1998(IC-W2A) IC-W2A Weak transmit audioTrouble: Weak transmit audio, deviation below the specifications, high end of the speech spectrum missing.Tools needed: A good soldering iron with a sharp tip, desoldering braid, solder, sharp-nosed pliers, small cross-pointscrewdrivers.Cure:1. Open the radio case following the instructions in the owner's manual (p. 45).2. In radios fitted with the UT-63 board, pull out the board.3. Unscrew the two small screws holding the tin plate against the bottom ends of the band modules. Pull out the plate.4. Pull out the band modules.5. Now you see the microfone fitted to the mother board. It should fit neatly against the inside of the fascia panel. If itdoesn't, carry on.6. Unsolder the microphone leads from the mother board. BE CAREFUL not to overheat the board and the wire insulation.7. Pull out the microphone and the rubber gasket.8. Re-install the gasket. Pull in the microphone so that it fits inside the gasket well and press it firmly to the end.9. Re-solder the mic wires. Install the band modules, the tin plate and don't forget the screws.10. Replace the rear panel.11. Tighten the 7 screws.12. Test the audio response.This modification is read 891 times.top of page