Technology of Q 2500 colour TV set
Changes to these values will be communi-4.2.10 Service mode
cated via the I2C bus to the appropriate proc-
essors during the adjustment procedure and In order to carry out chassis tuning the device
can then be adjusted to the required values. must be placed in the required service mode.
All data read in on start up as well as data The remote control can then be used to call
changed by the customer during operation, is up all the necessary functions for chassis tun-
checked during operation by continuous ing, with a few exceptions. After successful
communication between the SDA 6000 and tuning the new values must be saved.
the signal processors. If deviations occur
these are corrected immediately. The exact functions available in the service
mode can be found in the service instructions
for the appropriate device.
This is particularly the case for time-
dependent tuning values such as, for exam-
ple, white value, black value and c.r.t. leak-
age current. For this reason in devices incor-4.2.11 Video text
porating the Q 2500 chassis, ageing of, for
example, the c.r.t. only becomes apparent
when the scope of control is exhausted and In the 100Hz TV set system the videotext
the c.r.t. is totally worn out. In our chassis function and the production of overwriting
these dynamic tuning values are therefore OSD is now the responsibility of the CCU SDA
subject to special treatment. The values for 6000.
For this reason the FBAS signal is fed to pin
these functions held in the memory are auto-117 of the CCU. The CCU controls full data
matically updated to the current values on separation and memory administration inter-
each save procedure. In this way updating of nally. The VT pages are then stored in the
the current wear-determined values on start SDRAM I 2916.
up is not necessary, which the end user will The VT information as also the OSD overwrit-
surely notice.
ing are applied to pins 112/113/114 of the
For control and adjustment procedures via the CCU as RGB signals.
remote control and local operating buttons the
changes are initially made only in the working
4.2.12 Picture signal processing
memories of the appropriate IC?s and in the
register of the SDA 6000. Normally the saving Picture signal processing is implemented by
of values in EAROM must be implemented by highly integrated modern circuits that have
an additional command (usually the OK but-
ton). If the remote control is used to switch the been used for the first time by Loewe, in simi-
device to standby, then the data in the register lar IC variants, in the Q 2300 chassis genera-
of the SDA 6000 is available when the unit is tion. The highly integrated IC?s mean that for
restarted. The data within the unit, such as the the two 100 Hz generation chassis Q 2100
last volume level set is retained. and 2200, the 100 Hz module necessary for
the signal board can be dispensed with. All
the ICs necessary for signal generation can
When the unit is switched off at the mains the be fitted without problem on the component
microprocessor register is deleted, and on the side of the signal board. This also provides
next start up only the EAROM data is avail-much simpler faultfinding, which is also fa-
able. So that specific settings are retained, the
EAROM has an area for ?Last memory? data. voured by the clear signal flow.
On shut down the data is saved to this area
(e.g. last programme location). In addition, a
few seconds after programme location change
the set programme location is saved in the
Last Memory data area.
Document Q 2500 78 ? Loewe ProCollege |
ACEC
