[Yaesu] Again: DVS-2 audio improvement

[morel]

DVS-2 audio quality improvement

I'm posting once again this mod; anyway you can find all the Yaesu
reflector postings on the archives at: www.contesting.com

Problem: when DVS-2 is used with FT-1000D or FT-1000MP , FT-990,
the transmitted audio is distorted due to high output level . 

Note:this is a design problem cured by Yaesu as follows:

1. On the transceiver AF unit: change the R-3161 chip resistor
   from 1K to 4.7K ( for the "D" ); for the "MP" you have to find
   the similar resistor.

2. On the DVS-2 unit : 

   * on the top side of the board make an etch cut between C-1003
     and Molex connector J-1001 ( it's a very tight space ).
   * connect a 5.6K resistor from C-1003 nearest end to J-1001
     pin 6.
   * on the bottom side of the board, make an etch cut on the 
     trace placed at abt 1'' from the upper/rigt side of the J-1001
     solded pins.
   * add a 5.6K resistor across the etch cut you just made.
   * add a 5.6K resistor from the J-1001/Pin 5 to the nearest 
     ground trace. 
   * add a 5.6K resistor from J-1001/Pin 6 to the nearest ground
     trace.   

Dis-asembling the DVS-2:

1. The sole philips-screw closing the DVS-2 box is placed under
    the right-upper side rubber foot ,near the control cable.

2. After opening this screw, use a large flat screwdriver to open the
    plastic enclosure. Apply resonable force on every side of the
    enclosure. Pay attention to reset button and to lower side
    opening to prevent mechanical and/or estethical damages.

3. They are two cards inside: the upper PCB ( contents the keys , 
    leds and the switch; is fixed to front panel by screws ); the second
   is the component PCB with lots of SMDs. The connection between
   the two boards is done by a small unlocked SMD connector. Extract
   very carefully the bottom PCB from this connector and do the changes.

4. If the DVS-2 unit is in use more than one year, replace the 3V
    lithium battery model SONY CR-2032 ( with soldered pins for PCB). 
    The first models have some leakage and the back-up battery is being
    exhausted in less than one year. No need to replace the battery if
    the voltage measured is more than 2.8v.  

5. To re-assembly the unit, insert carefully the botom card into the
    upper card connector. Insert very carefully the bottom plastic
    enclosure into the front panel , paying attention to the control cable
    and to small reset button. Then, check for fully closure of the box
    and put inside the upper hole the philips-screw. Apply the sticky
    rubber foot over the screw head and that's all.

73 de Morel, 4X1AD



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