ICOM IC-2AT, IC-02AT Wright, Tim AL7DS: "Those Tantalizing Twos," _73_ magazine, June 1986 p. 60. Description of modifications requires illustrations. Article has very good mod for IC-2AT, to cover portion of 150 MHz range and preserve ham band. The IC-02AT modifications are valid only for units with serial numbers below 34000. A simpler IC-2AT mod is described in _73_, October 1981 p. 113. X-News: tesla rec.radio.amateur.misc:12147 From: wa2ise@cbnewsb.cb.att.com (robert.f.casey) Subject:mars/cap mod file for the IC2AT Date: 12 Jan 92 20:17:13 GMT Message-ID:<1992Jan12.201713.26613@cbfsb.att.com> copied from packet: Msg# TSF Size #Rd Date Time From MsgID To 10043 BF 2566 1 27-Dec 2052 N2MOD 2631_NY2S MODS@ALLUSA () Sb: Icom IC-2AT MODs. MODification File For ICOM IC-2AT --------------------------------- If you have studied the schematic diagram for this radio, you will notice that pins 15 and 16 are not indicated on the programmable divider chip IC1 (TC9122). By simply connecting pin 15 thru a switch to pin 1, you will be able to move the radio up in frequency by 10 MHZ. Some of these radios were sold without covering 140-150 MHZ. The modification for this extended coverage is described below: 1) Open up the radio and locate the FLEXIBLE BOARD, this connects the thumbwheel switches to the MAIN BOARD. 2) At the MAIN BOARD end of the FLEXIBLE BOARD, add a jumper at location C4. There should already be a jumper at location C2. 3) At the thumbwheel switch end of the FLEXIBLE BOARD, remove the jumper which connects C3 and COM. 4) Reassemble the radio. Coverage is now 140-150 MHZ.(MARS/CAP) Now, if you activate the switch described above, the radio will now operate in the 150-160 MHZ range, after L3 adjustment, described below. OPERATION and L3 ADJUSTMENT: ---------------------------- 1) Activate switch and dial up a known active frequency. 2) Adjust L3 until PLL locks up and radio begins receiving. (you need an active frequency to tell when this happens) 3) To return to 140-150 MHZ, repeat above steps with switch off. NOTES and DISCLAIMER -------------------- 1) Drill a hole in the case of the radio so that L3 can be adjusted from outside of the radio. 2) The above information is presented for educational purposes only, and is not an endorsement of any particular practice. 3) This MOD has been in operation for 6 years with no ill effects on the radio 4) This MOD courtesy N2MOD. -------------------------------------------------------------------------- Note: I haven't tried or verified this, proceed at your own risk. And do not transmit outside of legal bands! WA2ISE ========================================================================= Date: Sat, 24 Mar 90 15:00:22 EST From: mgb@tecnet1.jcte.jcs.mil Subject: IC-2SAT TX/RX mod I read a posting a few weeks ago where a gentleman was interested in any mods for the IC-2SAT that extended transmit or receive frequency range. I didn't pay much attention to it then, but when the XYL got one for me as a birthday present... that attitude changed markedly! :-) Well, I gathered up all I could find on the issue and broke out the soldering iron and took apart the radio that was less that one day old. (OH NO Mr. Bill!!!!) Here's the straight scoop and I HAVE tried this but you still proceed at your own risk (in case you were so foolish as to not know that :-) Take the battery cover off the bottom and remove the two screws. Remove two screws directly behind PTT button. Remove one screw where handy-carry strap goes. Gently pull on the front half of the radio and the radio will split apart but don't pull TOO far because the front half of the radio is still attached to the back half with that flexible plastic film wiring stuff. Fold front half to the right and lay it down. WARNING: The battery//cover release button can now pop out and a little itsy-bitsy tiny spring can take off for parts unknown. (Ask me how I know this... I spent 2 HOURS looking for that little sucker!) Pull the button out of the case NOW and watch out for that blasted little spring! All work is done on the circuit board inside the FRONT half of the radio (the part that you just pulled off). EXTENDED RECEIVE: Look along the RIGHT side of the circuit board and about halfway down the right side you will see a tiny circuit board that is mounted VERTICALLY on it, aligned from top to bottom. Look at the TOP of this little tiny board and you will see a normal diode (D-9) that is vertically mounted on the vertical board. Sounds confusing, but you can't miss it, it's right on the top end of the board. Cut this diode. Don't try to unsolder it... CUT IT. Take my word on it. WARNING: Don't pull the diode away from the board and leave it hanging. When you put the radio back together it is a very close fit and if you short the diode, the radio won't work. The PLL stays unlocked but no damage will occur. (yeah, I did that too :-) If you stop right here and reassemble the radio, you will now have extended RECEIVE capability after you reset the radio according to the instructions in the manual on the first page. And it REALLY is extended. My PLL was still locked up down around 88 Mhz and actually received FM broadcast stations although it obviously sounded BAD! :-) The radio freq. read-out now will go all the way up past 1 GHz, but that's just the dial read-out, check the Channel Indicator and when it goes to a "U" for "Unlocked" you can keep an eye on PLL performance, however I was amazed at where the PLL was locking up and the fact that it was actually receiving (albeit poorly) across a very very wide range. Yes, of course the sensitivity is way down the further you wander from the 144-148 design frequency range but it still is pretty impressive, and the new freqs. can be stored in memory and scanned. EXTENDED TRANSMIT: Look for the big IC directly in the middle of the main board on the front cover (IC-1 40608). Go to the bottom right corner of it. Move your eyes slightly to the right and you will see three chip resisters in a row. Just to the right of THOSE you will see three silk screened dots that are bracketed by a rectangle of white ink lines where a factory diode package would have gone. The "dots" form a triangle with one at the top and two at the bottom. Install a diode (1N914 or equivalent) with the cathode on the TOP dot and the anode on the bottom left dot. This will give you extended transmit from about 138-163 or so. But if you believe that trying to get a diode in there (without shorting out a lot of stuff) is impossible, (and you are very close to being correct) then FORGET this approach. Instead get Icom's diode DA (# 1750000160) and install IT in the same place. I tried using the 1N914, and it was a TOUGH job. It worked but looked horrible and was in imminent danger of falling off. I tried it out, verified that it worked... and pulled it right out. I have the diode DA pack on order now and will do it right when it gets here. I would politely suggest that you forget trying to use the 1N914 unless you have a micro-miniature repair facility at hand. (I did and still didn't like it). To avoid hate mail .... I have to remind you that it is illegal to transmit on the air with this radio out of the Amateur Bands unless a legitimate emergency exists. (Type acceptance and all that.) However if you (like me) plan on using it for a quick and dirty sig-gen into a dummy load, then it is the cat's meow! Mark Bitterlich WA3JPY mgb@tecnet1.jcte.jcs.mil ============================================================================= Date: 5 Jul 90 18:46:11 GMT From: noose.ecn.purdue.edu!rvl4.ecn.purdue.edu!cromwell@iuvax.cs.indiana.edu (Bob Cromwell) Subject: Icom IC-2SAT enhancements, part 2 To: info-hams@ucsd.edu A friend of mine in Germany mailed me a *very* intriguing photocopy of a letter he received from someone who works for Icom-Europe. It's an internal ICOM memo with details on how to do all sorts of nifty tricks with the IC-2SE (which may nicely translate to IC-2SAT tricks). I have attempted to exactly duplicate the memo below, mangled spelling, unclear passages, and all. I don't have an IC-2SAT service manual yet, and so I'm not qualified to say if this is all really applicable or not. And, the German at the closing is a mystery. I typed "fu:r" to indicate "fr". Anyone with more details, please let us know! Bob Cromwell KC9RG cromwell@ecn.purdue.edu ps: For the people asking "what was your original diode matrix, that appears at the end. There was some thought that the matrix programming changed after the first few (hundred? thousand?) models. This is from the schematic that came with mine, with serial number in the 9500's. pps: Before you ask "where's part 1", that was the article titled "Icom IC-2SAT", where I gave results of signal generator testing.... >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [page 1] ICOM ICOM (Europe) GmbH Himmelgeister Strasse 100 4000 Du:sseldorf 1 F. R. Germany Phone: 0211 / 34 60 47 Fax: 0211 / 33 36 39 Telex: 8588082 ICOM D To: Icom Dealer Dusseldorf, 14.4.89 I C O M S E R V I C E I N F O R M A T I O N I C - 2 S E Push Key + switch on Requested Mode Remark LIGHT + MON CPU RESET Clear all Memories LIGHT + FUNC FULL DISPLAY Display Func Test ---------------------------------------------------------------------------- LIGHT + V/M SIMPLE MODE Info on Equipment LIGHT + C (SCAN) MULTI-FUNCTION MODE Details in Handb. ---------------------------------------------------------------------------- LIGHT + FUNC + V/M RECEIVER MODE (All Band) All Band - no Tx ---------------------------------------------------------------------------- 1. Start SIMPLE MODE TRANSCEIVER MODE/ Tx only HAM-Band/ 2. Light + FUNC + C multi-function mode Rx see list below ---------------------------------------------------------------------------- Extent Transmitter Install Diode AD (D6) Tx: 139-163 MHz (FM) Manual AM/FM Mode Change all Bands: Rx Band Ranges: 1. Change to RECEIVER MODE (not receive mode) 75 - 106 MHz (FM) 2. FUNC + PTT (working in RECEIVER MODE) 108 - 130 MHz (AM) 138 - 169 MHz (FM) Note: (+) 174 - 192 MHz (FM) 1. keep pushing each key at same time, 204 - 243 MHz (FM) 2. switch on equipment, 250 - 291 MHz (FM) 3. hold (about 4sec.) until "SET" appear, 310 - 370 MHz (FM) 4. release keys and requested mode appear; Easily tunning step change (5 - 50 KHz): 1. push and hold FUNC key for 2sec. 2. rotate TUNING CONTROL. 3. Push FUNC to return to previous mode. Frequency ranges are appoximately and not garantied. Receiver sensitivity garantied only in HAM-Band (144 - 146 MHz). In RECEIVER Mode equipment running exclusively as a Receiver, cannot transmit at all. Achtung: nur fu:r den Fachha:ndler zum Zwecke des Service bestimmt. Es mu:ssen die Bestimmungen des Fernmelde-Anlagengesetz heachtet werden. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [page 2] IC-2SA/E Frequency range expantion * Remove any diode position on D6 * Install diode DA (code No. 1750000160) position D6 After this modification frequency lock range will be expand typicaly : RX (MHz) : 108 - 140 (AM) , 138-169 (FM) , 310-370 (FM) , TX (MHz) : 139 - 163 (FM) , ------------------------------------------------- | | | | | | | | | R R | | 3 3 | | 9 8 | | o | | R R R ### <--- | | 4 4 4 ### | | 1 2 3 o o R | | 6 | | ___________ 1 | | / \ | | / \ | | | SP1 | | | | | | | | | | | \ / | | \___________/ | | | ------------------------------------------------- >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [explanation of page 2] Yeah, the above is crude, just meant to give the relative locations of the mysterious diode, SP1, R38, R39, R41, R42, R43, and R61. The 3-terminal box with an arrow drawn to it (the arrow is in the original image) looks like the below. A diode is connected from the lower left tab to the upper tab. ___ | | -------------------- | / | | --- | | /_\ | | ____| | | / | | | | -------------------- | | | | --- --- >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [diode matrix programming] To simplify/fool-proof this, if the schematic has: (X) --->|--- (Y) I'll say "from X to Y". From the "IC-2SAT IC-2SET SCHEMATIC DIAGRAM": Japan Version D6: DA115 from KEYI2 to KEYS2 Europe Version D5: DA115 from KEYI0 to KEYS3 D6: DA115 from KEYI2 to KEYS2 Italy Version D5: DAN202U from KEYI1 to KEYS3 and from KEYI0 to KEYS3 D6: DA114 from KEYI0 to KEYS2 U.S.A. Version D4: DA115 from KEYI2 to KEYS3 D9: ISS254 from KEYI1 to KEYS2 Australia Version D5: DA114 from KEYI1 to KEYS3 D6: DA115 from KEYI2 to KEYS2 Asia Version D4: DA115 from KEYI2 to KEYS3 Now, can anyone use this to figure out the Icom-Europe memo??? Bob KC9RG cromwell@ecn.purdue.edu ============================================================================== From: TPDugan@dockmaster.ncsc.mil (Tim Dugan) Newsgroups: rec.radio.amateur.misc Subject: Icom IC-2SRA Mods Date: 29 Mar 1992 20:09:48 -0800 Organization: UCSD Usenet Gateway Lines: 145 Sender: daemon@ucsd.edu (The Devil Himself) Message-ID: <920330040824.343731@DOCKMASTER.NCSC.MIL> NNTP-Posting-Host: ucsd.edu I recently inquired about mods for the IC-2SRA, but didn't get any response, except for some requests to share anything I learned. So I figured it out myself, and here they are: IC2SRA Summary: Extended Receive, Extended TX (136-174 MHZ) Modification Instructions for the Icom IC-2SRA Handheld The IC-2SRA appears to be very similar to the IC-W2A, with a Wideband Receiver unit replacing the UHF RF unit. Not having an IC-W2A or the service manual for it, I can't be sure. This mod is very much like the IC-W2A mod by AA7BQ, which I used as a starting point. Extended Receive Right out of the box, the IC-2SRA Ham Band will tune 136-174 MHZ, and transmit 140-150 MHZ. Although the Receiver Band will tune 25-950 MHZ, sensitivity is better on the Ham Band side. Direct entry of frequencies outside of the amateur band is not as convenient as it could be. But there is an undocumented (by Icom) feature which makes it easier. Enable extended receive by holding down the 3, B, and # keys while turning on the power. Keep your fingers on the B and # keys for a minute, and you can see the full LCD function display. Besides what is normally seen, there are also VOX, TOT, RIT, and VXO displays. Makes one wonder if there are additional undocumented features? I haven't a clue! There are other key combinations which will do the same thing. With this done, the dial select step can be set to 10 MHZ, and the first digit for frequency input can be selected as 100 MHZ in SET mode. The display will now go from 50-500 MHZ, but don't think that you can receive in that range. You can believe signals in the 136-174 MHZ range, but outside of that you are most probably hearing images. Extended Transmit This is the fun part. The radio is designed to allow a wide range of applications, meeting amateur band requirements all over the world. This is accomplished with a diode matrix on the Logic unit. For the US, this involves diodes between lines D2 and 10 (D16), and between lines D3 and 11 (D22), on the Main CPU (IC2). To open up the full 136-174 MHZ range for transmit, diode D22 is removed, and diode D19 is instaled between IC2 lines D0 and 11. The diodes are very small three legged surface mount components. Icom doesn't publish any information on the CPU logic (that I know of), so I'm not sure just why any of this works. But it does work! Start by ordering one MA133 diode, order number 1790000860, from Icom America customer service in Bellevue, WA, at (206) 454-7619. Don't bother trying to order through one of the regional service centers, as they normally just forward part orders back to the corporate headquarters anyway. Cost in March 92 was $2.43, plus $1.75 handling. I don't know if they have a minimum; I ordered four diodes which brought the Visa charge to a litle over $10.00. When the diode arrives, it's time to open up your radio. You need a set of small Phillips head screwdrivers which can be found at any Radio Shack. Remove the five screws on the back, and two smaller screws on the side of the case under the PTT switch. Don't worry about the screw for the handstrap, it is screwed into the metal back and comes off with the back. With the screws removed, the back is easily lifted off. This much is shown pretty well on page 57 of the instruction manual where it talks about installation of the UT-63 (which is already installed in the US version of the IC-2SRA). Now remove the UT-63, and the PTT rubber. In front of you is the Receiver unit, stacked on top of the VHF RF unit, which is on top of the Logic unit. That is where we need to end up, so start disassembling. The Receiver unit is held to the VHF RF unit by a small screw on each side. You won't have any trouble figuring out which ones they are. There is also a small screw at the bottom of the Receiver unit, which fastens a spring clip holding the two units together. Remove the screws, and keep track of them. Both units are then individually removed by gently unplugging them from the Connector unit with a down and out movement. At this point you should be impressed by the well thought out design of the radio, and the ease with which it can be taken apart. In front of you now is the Logic unit, but there is a plastic encased metal foil, the CPU shield, still in the way. This shield is under the wiring harness between the Logic unit and the Connector unit. It isn't attached to anything, and can be gently curled and slipped out to the right. Here's kind of what you'll see under the CPU shield: IC1 IC2 --------------- --------------- ---- . . Time Clock Crystal -> X3 D16 ---- . . Periods "." -> .not used represent . ------ solder pads . . X4 <- Tone Clock Crystal D22 ------ . . . D19 . . . not used . Now the fun really begins! The diode that you received in the mail, and the one that you have to remove, are very small. They are also quite rugged, so don't let the size intimidate you. You do need to be clever about it though, and there is certainly more than one right way to go about it. You need a magnifying glass of some sort, and a fine tipped soldering iron. I wrapped a piece of solid No. 12 copper wire tightly around the tip of my 25 watt Weller. I brought a one inch lead straight out from the tip, and filed the end smooth. Ready for pin point soldering, start by removing diode D22. I put a knife blade under one end and applied light pressure while touching my No. 12 tip to the diode lead closest to the knife. Then the next lead, and the last one. Pops right off with no problem. You're not going to reuse it (unless restoring to original configuration), so it doesn't matter if it does get dinged up a bit. With D22 out, all that's left is installing D19. I used a pair of tweezers to place the diode in position, with the three leads sitting on top of the little blobs of solder already on the board. Then gently holding the diode in place with a toothpick, I tacked each lead in place. Don't add any solder, there's enough on the board already to do the job. After one lead is tacked down, the diode will stay in place without the toothpick. As I said, there are other ways to go about installing this very tiny diode (actually there are two diodes in the little chip), so do what makes you comfortable. Or find a friend with a steadier hand to do it for you! Now you just put it all back together again, starting with the CPU shield. If you have trouble sliding it into place, you might be trying to put it between the wiring harness and it's plastic backing. After the extended transmit mod the CPU resets itself (at least it did for me), but now you have the same features provided by the extended receive mod, without having to repeat the mod. You also can transmit 136-174 MHZ. As to be expected with a unit designed with 145 MHZ as the center frequency, performance varies. At 145 MHZ my handheld put out 7 watts into a dummy load. It does that throughout the 2 meter amateur band. At the ends of the "designed" transmit range, 140 and 150 MHZ, the power is down to 6.8 watts. Dropping down from 140 to 136 MHZ, the power is down to 6.2 watts. Going up from 150 MHZ, I got readings of 5.75 at 155, 4.25 at 160, 3.2 at 165, 2.2 at 170, and 1.75 watts at 174 MHZ. These readings are with a Radio Shack meter, so your mileage may vary. Nevertheless, a remarkable radio! Enjoy, and please don't transmit on frequencies you're not licensed for! Tim KA3YYP TPDugan@dockmaster.ncsc.mil ============================================================================