From: postmaster@asarin.ORG.AR
Newsgroups: rec.radio.amateur.equipment
Subject: Re: << HELP >> WANTED MODS...
Date: 7 Dec 93 12:57:57 GMT
Organization: ucsd usenet gateway
Lines: 124
Message-ID: <gate.a497Dc1w165w@asarin.org.ar>
NNTP-Posting-Host: ucsd.edu
Originator: daemon@ucsd.edu

Hi Chris (N0OXI) and ALL!

Here are some mods for the Yaesu FT-290r mkII radio...

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FT290.1

	FROM: M. P. ("JUG") JOGOLEFF, WA6MBZ
	      @ K6TZ BBS

	RE:   YAESU MICRO-PHONE NUMBER MH-15 C8.

        MOD.: HOW TO PREVENT THE TOUCH-TONE PAD FROM 
AUTOMATICALLY KEYING UP YOUR RIG.

	RIGS INVOLVED: THIS MIC. COMES WITH THE YAESU FT 290 MK 
II (2 METER RIG), THE FT 690 MK II (6 METER RIG), OR THE FT 490 
MK II (UHF RIG),  AND POSSIBLY OTHERS.

	1) TAKE THE THREE (3) BACK SCREWS OFF.
	2) TAKE THE TWO (2) SCREWS OFF THE CIRCUIT BOARD TO FREE 
IT FROM THE CASE.
	3) FIND THE RED WIRE GOING TO THE MICRO-SWITCH, IE, THE 
PTT LINE.
	4) FOLLOW THAT RED WIRE TO THE CIRCUIT BOARD.  AT THAT 
PLACE ON THE CIRCUIT BOARD ANOTHER RED WIRE WILL JOIN THE FIRST 
ONE.
	5) UN-SOLDER BOTH RED WIRES FROM THE CIRCUIT BOARD AND 
CLEAN UP THE SOLDER MESS, OTHERWISE HUM WILL OCCUR.
	6) SOLDER THE TWO RED WIRES TOGETHER AND COVER WITH TAPE 
OR SHRINK TUBING.
	7) PUT THE CIRCUIT BOARD IN PLACE AND SCREW IT DOWN.
	8) PUT THE "LOCK" SLIDE SWITCH BACK IN PLACE.
	9) PUT THE REST OF THE CASE ON.
	10) PUT THE OUTSIDE SCREWS IN.
	11) YOU ARE NOW READY TO TRY IT OUT, SO GO AHEAD AND RE-
ATTACH IT TO YOUR RIG!
	12) ALL SHOULD WORK:
	    PTT WORKS AND RELEASES,
	    MIC PASSES AUDIO,
	    TOUCH TONES WORK WHEN PTT BUTTON HELD,
	    TOUCH-TONE RED "LED" STILL LIGHTS UP WHEN TOUCH-TONE 
PAD KEYS ARE DEPRESSED, EVEN IF PTT BUTTON IS NOT HELD DOWN,
	    NO HUM NOTICED.

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FT290.2
		 FT-290R (first version)  Extensions
The pins no 38,39,40,41 near HMCS45C are used for extensions.
     PIN No          BAND         STEP FM/SSB              SHIFT
38   39   40   41     MHz         KHz     Hz    
--------------------------------------------------------------------------
*    *             140-150        25      1000           7.6MHz
                                 100       100
--------------------------------------------------------------------------
*    *    *        140-144        10      1000            1MHz
                                  20       100    
--------------------------------------------------------------------------
*    *    *    *   140-150         5      1000     no shift possible
                                  10       100
--------------------------------------------------------------------------
*              *   144-146       12.5     1000           600KHz
                                  25       100  (European version)
--------------------------------------------------------------------------
*    *         *   144-149        10      1000          600KHz
                                  20       100 
--------------------------------------------------------------------------
*         *        140-150        25      1000           5MHz
                                 100       100
--------------------------------------------------------------------------
     *    *        140-150        25      1000           5MHz
                                 100       100
--------------------------------------------------------------------------
     *    *    *   144-148         5      1000        600KHz
                                  10       100
--------------------------------------------------------------------------
     *         *   144-148         5      1000         600KHz
                                  10       100
--------------------------------------------------------------------------
          *        140-150        25      1000         1.6MHz
                                 100       100  (FB for 70 cm transverter)
--------------------------------------------------------------------------
          *    *   144-146        10      1000          600KHz
                                  20       100
--------------------------------------------------------------------------
               *   144-148       12.5     1000           600KHz
                                  25       100
--------------------------------------------------------------------------
*         *    * 143.5-148.5       5      1000            600KHz
                                  10       100
--------------------------------------------------------------------------
Thanks to F1GAN for this info.
                           73   Serge  F1EMT  @  FF6KDC

-------------------------------------------------------------------------------

FT290.3

				    FT-290R

There is a very "hard" de-emphasis in FT-290R. This can cause serious
problems copying packet signals with some demodulator chips, eg. like the
XR2211.
By a common request, here is a modification of this popular TCVR for packet
radio. It was made after a RADIO-REF article in several copies, by HA5OB,
HA5DI, HA3MA and others. Increasing the intelligibility in noisy environment,
this modification is also useful in FM voice communications.
You'll have to add only a serial RC unit, the R being 4.7 kOhm, and C being a
1uF tantalum capacitor. Put them between the pin 9 of IC Q1019 and the
collector of transistor Q1021, with the positive leg of the tantalum
capacitor to the collector of the transistor. These points can be found as
test points, near to IC Q1019. Solder the components together, wrap some
insulation around them, then solder to the test points mentioned. That's all
you have to do!
With this modification, FM reception will sound somewhat noisy, but much
louder.
73, Sanyi/HA3PG

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73's and Merry Christmas for ALL, de Ed - LU7AKC @ LU7AKC.#COL.CF.ARG.SOAM
<postmaster@asarin.org.ar>
