Grundig GV 27 EURO, Service Manual

Adjustment Procedures

GV 27 EURO, GV 7… EURO

k

 3 - 4

GRUNDIG Service

1.4 Chassis Board – Frontend (FV)

Test equipment: Oscilloscope with 10:1 Test Probe, Voltmeter, AF Millivoltmeter, Colour Generator

Service work after replacing the
… Tuner, IC7720, IC7721: Adjustments no. 2
… IC7720 (TDA9800T): Remove R3748 

(PLL)

. The new TDA9800T automatically sets a "Default" value.

… IC7780: Adjustments no. 4, 5

Adjustment

Preparation

Adjustment Procedure

1. Demodulator Circuit

PAL, F5725 

(AFC)

SECAM-L,
R3748

(Band I)

2. Delayed AGC

Voltage,
R3742

(AGC)

3. Residual Carrier

Band I,
F5721 

(40.4MHz)

4. Stereo Level

5. Cross Talk

Voltmeter: ................................. IC7720-(15) or IC7721-(20)
EE-mode.

Colour generator 38.9MHz - 500mV

PP

: ...... Tuner 1701-(17)

Colour generator 33.9MHz / 500mV

PP

: ...... Tuner 1701-(17)

Press button "SYSTEM" repeatedly until "SEC" is displayed.

Feed in a PAL white test pattern with sound carrier (without sound
modulation, Ch27, 74dB

µ

V aerial signal) into the warmed-up VCR.

Oscilloscope: .............................................. Tuner 1701-(17)
EE-mode.

Colour generator 40.4MHz - 300mV

PP

: ...... Tuner 1701-(17)

Oscilloscope: ........................................................ F1720-(1)
EE-mode.

Call up the Service Test Programme (see page 2-4).
Call up Level 60 (see page 2-4).

Call up the Service Test Programme (see page 2-4).
Call up Level 61 (see page 2-4).

Set the voltage with F5725 

(AFC)

 to 2.5V 

±

0.2V.

Set the voltage with R3748

(Band I)

 to 2.5V 

±

0.2V.

Set the amplitude with R3742 

(AGC)

 to 550mV

PP

 +0/-50mV.

Set the amplitude with F5721 

(40.4MHz)

 to minimum (5dB

lower at least than the input signal).

Observe the instructions for Level 60 (see page 2-6).
Terminate the Service Test Programme (see page 2-4).

Observe the instructions for Level 61 (see page 2-6).
Terminate the Service Test Programme (see page 2-4).

1.5 Chassis Board – Video/Chroma (VS, VS-S)

Test equipment: Oscilloscope with 10:1 Test Probe, Colour Generator

Service work after replacing the IC7007 or 7110: Adjustment no. 1

Adjustment

Preparation

Adjustment Procedure

The FMF signal must have an amplitude of 420mV

pp

. If the

value deviates by more than 

±

40mV

pp

 there is a technical

defect (e.g. IC7007).

Set Chroma signal with R3007 

(PAL-Curr.)

 to 160mV

PP

±

20mV

PP

(for 2-Head-VCR) or 130mV

PP

±

20mV

PP

 (for 4-Head-VCR).

Set Chroma signal with R3159

(SECAM-Curr.)

 to 210mV

PP

±

30mV

PP

.

Terminate the Service Test Programme, disconnect R3031
from L5001 and reassemble the drive mechanism.

Remove the drive mechanism (see page 1-9)
Call up the Service Test Programme – Level 10 (see page 2-4)
Feed in a PAL red raster test pattern with 75% saturation (ratio
burst: chroma = 1 : 2.2) into the AV1 socket and record it.
Oscilloscope: ................................  R3031 (T7006 – Emitter)

Connect R3031 (T7006 – Emitter) to L5001 (5VASW).

Oscilloscope: ................................................  R3007 – wiper
Feed in a PAL red raster test pattern with 75% saturation (ratio
burst: chroma = 1 : 2.2) into the AV1 socket and record it.

Oscilloscope: ................................................  R3159 – wiper
Feed in a SECAM-L red raster test pattern with 75% saturation
(ratio burst: chroma = 1 : 2.2) into the AV1 socket and record
it.

1. Chroma Recording

Current

PAL,
R3007

(PAL-Curr.)

SECAM-L,
R3159

(SECAM-Curr.)

1.6 Chassis Board – Standard Sound (AL)

Test equipment / aids: Frequency Counter, AF Millivoltmeter, AF Generator, Colour Generator, branded Video Cassette.

Service work after replacing the RP-Head, L5603 or IC7007: Adjustment no. 1, 2

Adjustment

Preparation

Adjustment Procedure

With F5603 

(BIAS R)

 set the frequency to 70kHz 

±

10kHz.

Set the voltage drop across R3600 with R3618 

(BIAS)

 to

15mV

rms

.

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 altered:
To increase the playback voltage at 8kHz: Reduce "BIAS".
To reduce the playback voltage at 8kHz: Increase "BIAS".

Set output voltage with R3160 

(PB-Lev.)

 to 0.5V

rms 

±

50mV.

Observe the instructions for Level 62 (see page 2-6).
Terminate the Service Test Programme (see page 2-4).

Frequency counter: ....................... wire bridge 9034 (Head)
Record

AF millivoltmeter: .......................... BIAS1 or BIAS2 (R3606)
Record.

– Feed in a CCVS signal via EURO-AV1 socket, contact 20.
– Feed an audio signal of 200mV

rms

 (480mV

PP

) from the AF

generator to the EURO-AV1 socket, contact 2 or 6.

– Make a recording of 400Hz and 8kHz each of 1 min at least.

Afterwards play back these recordings (MONO).

– Connect an AF millivoltmeter (oscilloscope) to EURO-AV1

socket, contact 1 or 3.

AF millivoltmeter: ............ EURO-AV1 socket, contact 1 or 3
AF generator (1kHz / 0.7V

rms

):

........................................ EURO-AV1 socket, contact 2 or 6

Feed in a CCVS signal via EURO-AV1 socket, contact 20.
Play back the self made recording (Normal Play).

Call up the Service Test Programme (see page 2-4).
Call up Level 62 (see page 2-4).

1. Erase Frequency,

F5603

(BIAS R)

1.1 Bias, R3618

(BIAS)

1.2 Frequency

Response Test

2. Playback Level for

Mono VCR,
R3160

(PB-Lev.)

for Stereo VCR