YAESU FT290R MODS 
     
    Most of these mods have been published at some time or other in 
    various radio magazines. 
    The ones marked with (()) I have not tried and cannot guarantee        that they work. 
    REMEMBER TO REMOVE THE NICADS AND DISCONECT THE POWER BEFORE            STARING ANY WORK ON THE 290 
     
     
    BRIGHTER RECIEVE AUDIO 
     
    First remove the lid from the set, then with the back of the set 
    towards you look in the bottom left hand corner and find the           relay. Just behind this are 2 green ceramic capacitors which form      part of a de-emphasis network comprising C110,C109,R82 & R89. Take     a pair of long nosed pliers, reach in and crush C110 which is the      one nearest the relay, then shake out all the bits.  
     
     
     
    ((RESET TO 145MHZ)) 
     
    This mod resets the cpu to 145mhz and sounds a bleep to tell you       its been done. 
    Remove top and bottom covers, locate the hole in the case near the     SO239 socket.It is covered by a stickon aluminium label. Make a        hole in this label and install a push to make, non-latching            switch. Connect one side of this switch to ground and the other        side to pin 4 of J5003 which connects the keyboard unit to the         control unit. A 1nf capacitor should also be connected from pin 4      to ground for decoupling. 
    Replace the covers dial up any frequency press the button and the      set should reset to 145mhz and bleep. 
     
     
     
    LISTEN ON INPUT 
     
    Place the set in front of you controls towards you, remove the         bottom cover and locate the black/white wire on SK1 its the tenth      one from the left. Cut this wire at the socket and insulate the        free end. Now find the green/white wire on SK1 and solder the          anode of a 1N4148 diode to it. Connect the cathode of the diode to     the red/white wire soldered to the pcb adjacent to the mic socket.     You must insulate the diode leads to prevent shorts. 
    Now when the call button is pressesd it allows listen on input on      both +shift and -shift. However when you want the rig to transmit      a toneburst you must close the PTT at the same time as pressing        the call button.         

                                    

    ((CURING SYNTHSISER WHINE)) 
    Early 290s suffered from a high level of whine you can try moving      the wiring harnesses around inside the rig whilst monitoring the       whine on another rig. The real cure on early 290s is, if you have      a delicate hand for soldering, locate LO6 in the synthesiser and       solder a 15pf capacitor in parallel with it. This can usually be       soldered between the hot ends of C24 & C25 which are at the rear       of the IC in the synthesiser unit.  
     
      ((MODIFIED SQUELCH)) 
     
    This mod reduces the difference  in  level  between  the  opening      and closing points and speeds up the operation of the squelch          enabling the scanner to work better. 
    To do this mod reduce C94 from 4.7uf to  1uf,increase  R79  from 
    270kohm   to   330kohm  and  add  a  10uf  tantalum  or  sub           miniture electrolytic between the  leg  of  R78  (4.7k)  to  the       body  of  the transistor T1007


    PORTED AND REALIGNED FROM PC TO AMIGA FORMAT BY BOB G0LBQ - N6XDI.