Msg Nr. : 33977 Da : EA5XE Per : MODS @EU Tipo/status : B$ Data/ora : 0821/0423 Dimensione : 3472 Titolo : Alcune modifiche per l' FT 990 . Bid (Mid) : 702_EA5XE YAESU FT990 - 1.5 to 30 MHZ TX mod: ----------------------------------- -Open FT990 like explained in your OPERATING MANUAL. -Localise JP5002 on "CONTROL UNIT" and close it with solder. -If no transmit between 4 to 6.5 MHZ and 8 to 10 MHZ, do the following: 1) Display 5.5 MHZ in CW mode, "meter selector" to ALC, push "MOX" button and adjust VR1003 on "RF UNIT" for normal ALC meter deflection. 2) Display 9 MHZ and do the same with VR1005. / \ -- -- -- 73 de Romualdo (Ї..Ї) / EA5XE @ EA5XE.EAV.ESP.EU Msg Nr. : 49373 Da : IW3GRX Per : MOD Tipo/status : PN Data/ora : 0521/2129 Dimensione : 5627 Titolo : Alcune modifiche per l'FT990 Bid (Mid) : 4354_IW3GRW ллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллл From : N3GPP @ N3GPP.#EPA.PA.USA.NA To : MOD @ ALLUS Date : 920202/1710 Msgid : BF 6@N3GPP, 5258@W6VIO $6_N3GPP Subject : YAESU FT-990 GENERAL COVERAGE TRANSMIT MOD FOR MARS OPERATION YAESU FT-990 REMOVE TOP COVER LOCATE AND REMOVE CTRL BOARD (CTRL BD. IS THE FAR RIGHT VERTICLE BD LOOKING AT THE TRANCEIVER FROM THE FRONT. REMOVE TWO PHILLIPS HEAD SCREW AND LIFT OUT BOARD.) LOCATE JP5002 (JP5002 IS LOCATED ON THE FAR RIGHT OF THE PC BOARD NEAR THE TOP OF CHIP Q5016. Q5016 IS THE THIRD BIG CHIP LOCATED AT THE FAR RIGHT OF THE PC BOARD.) SOLDER JUMPER JP5002 RE-INSTALL BOARD SET MODE TO CW METER TO ALC RF CTRL FULLY CLOCKWISE ADJUST VR1003 AT 5.000 Mhz TO FULL ALC METER READING. ADJUST VR1005 AT 8.000 Mhz TO FULL ALC METER READING. VR1003/1005 ARE LOCATED ON THE FAR LEFT VERTICLE BOARD LOOKING AT THE TRANCEIVER FROM THE FRONT. THE POT ARE ADJUSTABLE FROM THE TOP. THERE IS NO NEED TO REMOVE THIS BOARD. RE-ASSEMNBLE THE RADIO AND YOU ARE READY TO GO. I WOULD LIKE TO HEAR OF ANY OTHER MODS AVAILABLE FOR THE FT-990. I'AM SURE THERE IS A LOT OF STUFF THAT CAN BE DONE THROUGH THE KEYPAD LIKE ON THE KENWOOD TS-850. 73'S BOB ллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллл From: wa2ise@cbnewsb.cb.att.com (robert.f.casey) Newsgroups: rec.radio.amateur.misc Subject: FT990 and 1000 extended xmit mod file Keywords: mod file Message-ID: <1992Apr4.145318.5487@cbfsb.cb.att.com> Date: 4 Apr 92 14:53:18 GMT Sender: news@cbfsb.cb.att.com Organization: AT&T Lines: 18 copied from packet: Msg# TSF Size #Rd Date Time From MsgID To 7086 BF 1241 0 28-Mar 1106 F6HKA 80214_FC1MAC MODS@WW () Sb: Modification FT990-1000 I received a mail from AA6SQ about Extended transmitter frequency range for FT990 and FT1000 -Remove top and bottom covers. Remove top screw on each side which holds front panel to chassis. Pivot front panel down slowly. CAUTION : if you let it go, it will flop down rapidly and probably tear somethins loose. Behind the meter will be the CNTL unit. It has a metal cover about 4 * 8 inches. Snap the cover off. Look to the top of the unit. You will see JP-3. Remove the solder connection on JP-3. Best 73 and good traffic on HF bands . Bert fF6HKA ========================================================================= Note: I haven't tried or verified this, proceed at your own risk. And do not transmit outside of legal bands! WA2ISE ллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллл Article: 32166 of rec.radio.amateur.misc From: kchen@Apple.COM (Kok Chen) Newsgroups: rec.radio.amateur.misc Subject: Re: FT990 mod for extended tx Message-ID: <76900@apple.apple.COM> Date: 17 Jan 93 23:01:05 GMT References: <1jcftdINNh42@tamsun.tamu.edu> Organization: Apple Computer Inc., Cupertino, CA Lines: 51 blw7149@tamsun.tamu.edu (Brandon Lee White) writes: >I received a mail from AA6SQ about Extended transmitter frequency range >for FT990 and FT1000 >-Remove top and bottom covers. Remove top screw on each side which holds >front panel to chassis. Pivot front panel down slowly. CAUTION : if you >let it go, it will flop down rapidly and probably tear somethins loose. >Behind the meter will be the CNTL unit. It has a metal cover about 4 * 8 >inches. Snap the cover off. Look to the top of the unit. You will see >JP-3. Remove the solder connection on JP-3. This appears similar to the mod given for the FT-1000 that is given in "Radio/Tech Modifications, Volume 5B," ISBN 0-917963-011-3, published by artsci, inc. BUT! The mod for the FT-990 that appears in the same book is completely different. I tend to believe the book, since the control unit for the FT-990 is on a plug-in card to the motherboard, and not a thing attached to the front panel. I did not attempt to make the extended range mod, but I did make a mod to my FT-990 (didn't read of this mod anywhere, I simply traced the schematics) to reduce the minimum power output from 10W to about 3.5W, to operate QRP using the last ARRL 10m contest. (I just felt like getting 59 reports from everyone that weekend, and, except for one truthful gentleman in NC, I did :-). I didn't blow anything up, but do the following at your own risk. Find the R.F. power control pot in the schematics. All this pot does is to supply a variable voltage level to the ALC circuitry. Trace the signal from the pot to the ALC goodies, and you will find a series limiting resistor whose value is 1/10 that of the pot's max value. This is what limits min power to about 10W. I simply paralleled this fixed resistor (a surface mount resistor on the board with the ALC sensing circuitry) with a smaller axial resistor. You have to raise power to 8W or so to get the automatic antenna tuner to buzz and click. That may be why the power control knob would not go below 10W on a stock unit; would only confuse all the appliance operators :-). BTW, has any other FT-990 owners noticed that the built-in computing SWR meter is quite inaccurate at powers below 25W? 73, Kok Chen, AA6TY kchen@apple.com Apple Computer, Inc. ллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллллл