Yamaha HTR-5450 Service Manual page 11

Besides the above possible causes, the cause may be a disconnected connector or around the CPU.
PS PRT and DC PRT displays include the abnormal A/D value in % (voltage value obtained by considering 5V as 100%).
Concerning this value, refer to DIAG menu No.11 AD DATA CHECK.
• Protection history
When the protection function has activated, its history is stored in memory with a memory backup. Even when no
abnormality is noted while the unit is being serviced, an abnormality which has occurred previously can be defined as
long as the backup data has been stored. The protection history should always be cleared before returning the unit
from service.
The protection history is cleared when DIAG is cancelled by selecting "RSRV" (Memory initialization) from the setting
items of the DIAG menu No.10 PRESET or when the backup data is erased.
• Operation procedure of DIAG menu and SUB-MENU
There are 14 MENU items and some SUB-MENU items as well.
DIAG menu selection
Main unit: Select the menu using ∞ (Forward) and § (Reverse) keys of
PROGRAM.
Remote control unit: Select the menu using
SUB-MENU selection
Main unit: Select the sub-menu using ∞ (Forward) and § (Reverse) keys of
PRESET/TUNING.
Remote control unit: Select the sub-menu using
keys.
* Only the remote control keys indicated in the MENU List can be used to select
a sub-menu directly.
• Functions available during DIAG
In addition to the DIAG menu, functions as listed below are available.
• Input selection, 6CH input
• Center/Rear/Sub-woofer level adjustment
• Muting
• Power on/off operation
* Functions related to the tuner and the set menu are not available.
* It is possible to confirm Menu No.12 "IF STATUS" while keeping the signal process (operation status) of each DIAG menu
by using the INPUT MODE key of the main unit.
PS PRT display
(When the power is turned on without this abnormality corrected, the protection
function activates about 1 second later to shut off the power relay. Display may not
light if there is an abnormality with the power supply for the display.)
Cause: There is an abnormality in the power supply section (voltage).
Supplementary information: As the power from the following sources is detected, it
is possible to determine where an abnormality exists.
Main (5): Transformer secondary winding
CB222 (AC voltage)
Input (4): Regulated power supplies
±25, +12A, +12B, -12, +5D
DC PRT display
(When the power is turned on without this abnormality corrected, the protection
function activates about 3 seconds later to shut off the power relay.)
Cause: A DC output from the power amplifier of any channel is detected.
(Forward) and (Reverse) keys.
(Forward) and
RX-V520/RX-V520RDS/HTR-5450/HTR-5450RDS
DIAG menu selection
PRESET/TUNING
SUB-MENU selection
(Reverse)
PROGRAM
Use these keys for
DIAG menu selection.
Use these keys for
SUB-MENU selection.
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