Alignment - Grundig STC 50 Serviceanleitung

Abgleich / Alignment

Alignment

All filters and adjustment controls not mentioned in this description are pre-set at the factory and must not be re-adjusted in the case of repairs.
Filters must be replaced in service by a new pre-set one.
Measuring works after replacement or repair:
SAT-Tuner and peripherals
Alignment
Video level Switch the unit to SAT reception (e.g. from the Astra
satellite) then adjust the correct video level (Astra 16MHz).
Oscilloscope: modulator Pin 5
Trigger the composite signal to video frequency.
Inject a SAT generator with ±50kHz AF amplitude via the
AF1 amplitude
SAT input.
Connect a measuring receiver to the output (associated
output channel).
Inject a SAT generator with ±50kHz AF amplitude via the
AF2 amplitude
SAT input.
Connect a measuring receiver to the output (associated
output channel).
Modulate the right AF channel.
Test point: left AF1 channel.
Pilot tone Inject a test pattern via a SAT generator (2.5kHz).
Set the pilot tone to normal position.
Select the audio mode "Stereo/two-channel sound " in the
"Audio" dialogue line of the "Channel programming" menu.
Connect a measuring receiver to the output (associated
output channel).
Residual carrier Inject a colour test pattern via a SAT generator.
Note:
The alignment has to be carried out for every line.
2 - 2
Preparation Alignment procedure
Use R02015 to adjust the amplitude of the composite
signal to 425mVpp.
Use R07205 to adjust the audio level to ±50kHz amplitude.
Use R07105 to adjust the audio level to minimum stereo
crosstalk.
Check with the stereo/two-channel audio setting whether
the TV set displays these functions.
Use R07015 to adjust the pilot tone to ±2.5kHz.
According to picture quality / 1V at decoder socket.
No intercarrier hum is allowed to be heard. Otherwise use
R02015 to reduce the amplitude until the hum is no longer
audible.
STC 50
GRUNDIG Service