Subject: R7000 Display/Sensitivity Problem

If you are having trouble with you Icom R7000 display being flaky
and then a sudden decress in sensitivity try the following:


PROBLEM:   ICOM R7000 radios that are used 24 hours a day for a long time
           (2 years ) when shut off the display will become flaky and it
           is also possible for a lost in overall gain (3 to 40 db).

SOLUTIONS: Officially there is ICOM ECO SB# 9288-004, attached below.

           Unofficially from Tech who repairs R7000
           The ECO does help the display problem, but most likely
           it is not the problem. 


1st SOLUTION:
    Replace the following capacitor on the DC to DC Board.
    Check the noise with an oscilloscope on both sides of
    R3, if the noise is not way down on one side then
    replace C2 a 33uf 16V capacitor. Noise feedback
    can decress the overall sensitivity of the R7000.

    Replace C19 and C20 on the display Board
    with a 10 uf 16VDC capacitor.

     I found that on my R7000 C19 & C20 were the cause of my
     display problems.  They are 10 uf eletrolytics capacitors
     that are lemmon yellow pc mounted units, when they go bad
     the base of the yellow caps change to a brown color.

     I put in the following ECO first but it did not help.  If
     you look at the service manual you will see that the ECO
     values are on the schematic but my unit had the old values.
     I suggest that you check the above first, it is a lot easier
     to do, C19/C20 can be done in 10-15 min while the ECO will
     take about a hour.


2nd SOLUTION:  The ECO

ICOM America, INc
2380-116th Ave, N.E.
Bellevue, Washington 98004
206-454-7619

BACKGROUND INFORMATION:
    Display failure do to weak components

TECHNICAL INFORMATION:
    Improvement in DC to DC converter and display power supply.

PARTS AFFECTED    BOARD TYPE        CHANGE TO      NEW PART NUMBER
Q1/Q2 2SC 1214    DC to DC Board    2SC 2655       906-00385
R1/R2 3.3 KOHM    DC to DC Board    5.16 K         915-01173
C3/C4 PF          DC to DC Board    0.001 MF 50V   918-01500
                                    ceramic cap

Q11/Q12           Display Board     2SC2655        906-00385
R31/R32 3.3KOHM   Display           5.16k Ohm      915-01173
C13/C16           Display           0.001 MF       918-01500

DETAIL PROCEDURE:

 1.  Remove top and bottom cover.
 2.  Remove front panel sub-assembly from main chassis of radio
 3.  Remove the DC to DC board and replace components as listed
 4.  Reinstall DC to DC board.
 5.  Replace front panel sub-assembly onto main chassis of radio
 6.  Replace top and bottom covers.