home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
World of Ham Radio 1997
/
WOHR97_AmSoft_(1997-02-01).iso
/
mods
/
icom
/
icom_r
/
r7000_00.doc
< prev
next >
Wrap
Text File
|
1997-02-01
|
2KB
|
45 lines
R7000
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 40db).
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. *
* note 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 decress 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 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.
CONT IN R7000.1