k
3 - 6
GRUNDIG Service
Adjustment Procedures
TVR 3710 …, TVR 5100 …, TVR 5500 …
3.3 Signal Chassis – Deck Control / Deck Electronic (DE)
Test Equipment / Aids: Test Cassette
Alignment
Preparation
Alignment Procedure
1. Head switching
position (GAP)
Play back the test cassette and press one of the buttons
x
/
c
on the remote control.
On successful alignment the TVR switches to stand-by.
If the procedure was not successful, the TVR ejects the test
cassette.
Causes: Test cassette, headwheel or technical defect
(e.g.
µ
C)
3.4 Signal Chassis – Frontend 2 (TU2)
Test Equipment / Aids: Digital Voltmeter, Oscilloscope
Alignment
Preparation
Alignment Procedure
1. Demodulator
circuit
PAL, L5303
(AFC2)
SECAM-L,
R3322
(L´ADJ2)
2. Start-up of the
tuner control
voltage
R3341
(AGC2)
Connect tuner 1301-(5) to GND.
Digital voltmeter: ....................... tape deck – IC7410-(61)
Reception: PAL-BG
Colour generator 38.9MHz, 35mV
rms
to tuner 1301-(17)
Reception: SECAM-L, band 1 (channel 04)
Colour generator 33.95MHz, 35mV
rms
.... tuner 1301-(17)
R3341 "fully clockwise"
Feed in a white test pattern without sound carrier (UHF range,
channel 24, 67dB
µ
V aerial signal) into the warmed up TVR.
Oscilloscope: .......................................... tuner 1301-(17)
With L5303
(AFC2)
set the voltage to 2.5V
±
0.2V.
With R3322
(L´ADJ2)
set the voltage to 2.5V
±
0.2V.
Remove the ground connection.
With TDA9800T/V3 (IC7300) fitted:
With R3341
(AGC2)
set the voltage to 500mV
pp
-1dB.
With TDA9812T (IC7301) fitted:
With R3341
(AGC2)
set the voltage to 400mV
pp
-1dB.
3.5 Signal Chassis – Video/Chroma (VS)
Test Equipment / Aids: Blank Cassette, Oscilloscope with 10:1 Test Probe, Frequency Counter, Colour Generator
Alignment
Preparation
Alignment Procedure
1. Sync frequency
R3010
(SYNC-FREQU.)
2. Chroma recording
current
PAL
R3029
(PAL-CURR.)
SECAM-L
R3027
(SECAM-CURR.)
AV recording without input signal
Frequency counter: ............... connector contact 1902-(2)
Connect IC7051-(2) via 150
Ω
and 22
µ
H to +5V supply.
Oscilloscope: ........................ connector contact 1902-(2)
Feed in a PAL red raster test pattern with 75% saturation
into the AV socket and record it.
Feed in a SECAM-L red raster test pattern with 75%
saturation into the AV socket and record it.
With R3010
(SYNC-FREQU.)
set the frequency to 3.8MHz
±
10kHz.
With R3029
(PAL-CURR.)
set the chroma signal to 85mV
pp
(-12.5dB of the FM signal).
With R3027
(SECAM-CURR.)
set the voltage to 55mV
pp
(-17dB
of the FM signal).
Remove the150
Ω
resistor and 22
µ
H coil.
3.6 Signal Chassis – Standard Sound (AL)
Test Equipment / Aids: Blank Cassette, AF Voltmeter
Alignment
Preparation
Alignment Procedure
1. Bias (70kHz),
R3618
(BIAS)
1.1 Frequency
response
2. Playback level
R3606
(PB-LEVEL)
Record any signal.
Measure the voltage drop on R 3600 with AF voltmeter.
– Feed in a CCVS signal via AV socket, contact 20.
– Feed an audio signal of 50mV
rms
from the AF generator to
the AV socket, contact 2 or 6.
– Record the 400Hz and 8kHz signals each for 1 min at
least. Afterwards play back these recordings.
– Connect an AF millivoltmeter to the AV socket, contact
1 or 3.
Sound generator (1kHz / 0.5V
rms
): ....................................
................................................. AV socket, contact 2 or 6
Record (Normal Play).
Play this recording back.
Adjust voltage drop on R3600 to 15mV
rms
with R3618
(BIAS)
.
Check the frequency response.
The voltage ratio of 400Hz to 8kHz must not be higher than
1:0.7 or 0.7:1 (
±
3dB). If the voltage ratio exceeds these
limits, the bias must be corrected:
To increase the playback voltage at 8kHz: reduce "BIAS".
To reduce the playback voltage at 8kHz: increase "BIAS".
With R3606
(PB-LEVEL)
set an output level of 0.5V
rms
Load the test cassette and call up the Service Function:
– Press button
¢
■
(STOP) on the remote control followed by
¢
e
(playback) on the local keyboard and hold them down for
5s at least.
– With button
G
on the remote control call up the "SERVICE
CONTROL" function.
– With button
]|
on the remote control call up the "GAP
POSITION" function.
