The World of Free Packet Radio Software Amsterdam The Netherlands
THE WORLD OF FREE PACKET RADIO SOFTWARE AMSTERDAM THE NETHERLANDS
THE NL3ASD MODIFICATIONS PAGES - THE R7000 DISPLAY PROBLEM
MODIFICATIONS FOR THE R7000 DISPLAY SENSITIVITY PROBLEM
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.
NOTE
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.
SOLUTIONS
Repairing your own radio my void you warranty and only allow a qualified technician to do the job, otherwise damage could happen to your R7000.
If the VCO does not track then a major alignment would have to be done after.
Check the ICOM IC-R7000 Service Manual for more details before starting this repair, and to make sure I have not made any typeing errors you should get a copy of the ECO from ICOM.
1ST SOLUTION
Replace on the DC to DC Board the following capacitor. 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
decrees
the overall sensitivity of the R7000. Replace on the Display Board C19 and C20 a 10 uf 16VDC capacitor I
found that on my R7000 C19 & C20 were the cause of my display problems. They are 10
uF electrolytic
capacitors that are lemon 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
SERVICE BULLETIN UNIT MODEL R7000 SB# 9288-004
EFFECTIVE DATE 4/1/88
SERIAL #
AFFECTED: ALL PRODUCT
GROUP: Amateur
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 NUMBERS
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.
7. Estimate time to complete is 1 hour
8. Page 2 of the eco has a new schematic but no information
