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For Authorised Service Agents Only
Ref No: 339643015367487SHR
Date: 05/10/2009
TECHNICAL INFORMATION Created by
Panasonic UK - Service Group
Document Category: Knowledge Base
Subject: ERROR CODE
Model(s) Affected: DMR-EZ45VEB DMR-EX75EB DMR-EX85EB DMR-EZ25EB DMR-EZ27EB
Problem / Issue U80 and U81 Fault Code
Solution: See Below
The U81 code indicates errors on the IIC data lines between the freeview (called backend PCB) and digital
PCB which control the recording functions.
The U80 code indicates errors on the IIC data lines between backend and timer IC on main PCB which
control the boot up/remote functions
1) Reflow the on board flash ROM and memory on the backend PCB--some dealers report this as curing
intermittent U80/U81 codes.
2) Also check and reflow the edge connectors on backend PCB and main PCB. Also check/ reflow the
soldering of the digital PCB's connection socket on main PCB.
3) Using an oscilloscope, check all LT supplies to digital PCB and backend PCB areas are OK (free of
ripple)> see circuit board interconnection diagram (in service manual) to easily check what voltages are
going these pcbs.
CHECK THE BACKEND PCB 3.3V 12V, 1.8V LINES CAREFULLY AS NOISE /RIPPLE ON THESE LINES
MAY CAUSE PROBLEMS.
See the unit's interconnection diagram in the service manual for an easy view of PCB interconnections and
voltages on socket pins.
See attached diagram for example from ex75 of interconnection diagram
4) If the unit is working and fault intermittent, upgrade the unit's firmware -available from (Pananet System)
5) Next, carefully reflow inside of tuner and retest > especially the surface mount ICs in the tuner. After
reflow clean the PCB thoroughly with flux cleaner. C304 (electrolytic) on the tuner PCB may also be
replaced.
6) Replace tuner if fault persists and retest. Also inspect the soldering in the new tuner as in point 5.
7) If the above fails to cure the issue then replace the freeview backend PCB and retest and go back to
step 1 if necessary.
8) Some dealers report that using used 3 or 6dB attenuators (in aerial feed) to bring down high signal
strengths stops intermittent U80/U81 codes.
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Use a digital strength meter to look at aerial levels. If they are high, try an attenuator. The unit's own signal
strength meter in the menu can also give an idea of strengths. Typically if the strength bar is already 100%
then try a 3dB or 6dB attenuator to see the problem improves.
Trying a 6dB attenuator in line with aerial can be an effective test.
Most aerial systems should have a least this level of safety margin in the signal strengths (good aerial feed
etc) before blocking and pixilation occur. The benefit of this is that it may also take down unwanted MUX
signals that are causing the decoder problems.
If problems persist then email AV technical with the following:
1. Serial and model numbers
2. Software versions levels > noted from the service mode> see service manual
3. The channels being viewed when the error happens > MUX2 channels (itv and ch4 dvb) seems to be
more problematic!> but please confirm
4. How often the fault occurs in a week or day
============
Please check that C1801 is not leaky or S/C if so IC1801 will also need to be replaced these components
are located on the POWER/DIGITAL IF PCB.
The IC supplies the 1.8 Volt rail. Please see attached foil layout for location.
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