PHILIPS
ŠASIJA
GR1AX
MREŽA
Line transistor T7528 defect (4822 124 40754).
1: A defective line transistor T7528 can be caused by a defective C2523 (6.8µF/50V). To prevent reoccurance, replace C2523 with a 68µF/63V capacitor, code number 4822 124 40754.
Line end stage does not function UB is present - 5V is present - D6058 u6030 C 2058 R 3058 ok. 1: Check C2523.
Failures in the power supply.
1: In the event of a failure in either R3616, R3680, R3614, MOSFET 7610 or D6610, it is recommended that all five components should be replaced. During finding do not connect any probe to the gate of the MOSFET 7610 to measure voltages and waveforms as this would disturb the normal operation of the device resulting in its damage or
complete failure. |
|
|
|
||
Check/replace: |
|
|
|
||
TS 7610 (BUK 444-500B; 4822 130 61676) |
D 6610 (BZX79-C10; 4822 130 61219) |
||||
R |
3616 |
(1 Ohm; |
4822 052 11108) |
R 3680 (1 Ohm; |
4822 052 11108) |
R |
3614 |
(6.8 kOhm; |
4822 053 11681). |
2: Check D6613, R3100, IC7103 and Set dead. |
|
Set dead.
Restriction: for sets with serial no. SV.. only. If thyristor 6641 is disconnected, the set starts up.
1:[Due to action of over-voltage-protection circuit]. Disconnect T7100 and see if the set comes on, if so suspect T7100 (4822 130 40947) or a on the 9 volt rail, probably an audio .
2:[Due to action of over-voltage-protection circuit]. If the audio output IC7103 is disconnected, the set starts up. Check if IC7103 (4822 209 60956) or the loudspeaker is defective.
3:[95V line low at 15V]. Cause of the was in the chopper driver
transistor's base circuit, where C2618 (27nF) O/C. It is of the blue plastic block type.
4:[Line output transistor TR7528 (2SC3795) S/C]. Replace TR7528 and check C2523 (6.8uF/63V) for O/C.
5:Check D6613 (15V), D6610 (10V) and D6644 (1N4148) for leaks; line output transistor for S/C and check microcontroller chip TMP47C4323559.
Set dead. Power supply tripping.
1: 95 volt line pulsing. Check/replace RR3614 - 6.8k in chopper driver coupling circuit. REMARKS:
This component may have been strained or failed after a FET failure.
Slow start up of power supply.
1: Replace zener diode D6613 (15V).
Line transistor 7528 blows within 1 sec.
1: Check if IC7020 (TDA8305) gives output. If not, replace IC7020 REMARKS :
Code numbers of line transistor:
BUT11AF 4822 130 42679 BUT12AF 4822 130 43919.
2: Check the small 3.3µH choke L5519 which is in series with the output from the chip (IC7020).
Intermittent dead.
1:Transistor 7521 base loose.(dry joint).
2:L5524 a small coil which filters the supply to the line driver stage is O/C.
3:[95V HT supply OK]. Check C2523 (6.8uF).
No +9V, line output stage is OK.
If no +9V starting voltage, check D6523 for open circuit. (4822 130 61219).
Power supply not working.
Check D6610 for short-circuit (BZX79-C10; 4822 130 61219).
Power supply does not oscillate.
Check C2613 (33nF; 4822 121 42489) on leakage.
Dead, 95V line low at 15V
1: Cause of the was in the chopper driver transistor's base circuit, where C2618 (27nF) O/C. It is of the blue plastic block type.
tripping
1: TDA7052 sound output chip.
No voltage from PSU. +5A present.
1: Check TS7610, TS7614, TS7629, D6610 and D6613. If TS7610 is defective also replace diodes 6610, 6613 and check R3616 and R3680 with the ohmmeter.
No voltage from PSU, computer does not work. +300V present but not +5A.
1: Trip circuit has reacted. Operate with 70V input voltage (variable isolating transformer). If +95V remains below 95V, it is present. in the voltage control. Check TS7628, TS7614, diode 6614 and R3627/3629. If +95V is still not present, remove diode 6638 and switch on with 70Vpp. Now +95V is almost present. Replace diodes 6638, 6639 and 6640.
Line output stage only starts up for a short time, 95V is present.
1:Check electrolytic 2523 which has a loss of capacity.
2:Check start circuit for line oscillator. Consists of diodes 6058 and 6030, electrolytic 2058 and resistor 3058.
NB: These parts are at the control input for the volume. |
3: Check coil L5524 (1.5mH) in the +9V line for O/C. |
PSU repair tip.
Warning: Please do not test on the mains switching transistor! (field effect). May be destroyed. An incandescent lamp is unsuitable as a dummy load. Perhaps PSU does not start up.
Dead.
1: Check 12V zener diode D6030 O/C.
2: Check sound chip and zener diode.
3:From a visual check fuse 1600 2A is "black". Joints of thyristor 6641 (SF2D41) between anode and cathode S/C and at a following test also diode 6642 S/C. Replace both components.
4:Line output transistor S/C, also line output transformerfaulty. On replacing transistor it blows again after a few mins, check L5519 (3.3uh) choke for shorted turns.
5: Check if D6638 is S/C, +94V line, if low check C2618 O/C. |
6: [95V very low]. Check D6671 (BZX79-F4V3). |
7:[PSU ok, no 95V and 9V]. Check TR7100 (BC558A), safety resistor R3100 (1R) and IC7103 (TDA7052).
8:[No 95V]. Check D6638 (BZX79-B36) for S/C.
9:[No line drive]. Check D6030 (12V zener), D6523 (1N4148) and L5524 for O/C.
10: [No output from chopper]. Check D6610 (BZX79-C10). |
11: Replace R3610, R3513 and D6610 (10V). |
No function. Standby LED flashes briefly. 95V and 5V present. Only 4.5V in 9V line.
1: [Replaced audio IC. No result]. TDA8305 is defective causing TR7521 to remain in conduction. 7523 is not driven preventing line oscillator from starting to oscillate. Replace IC.
Appliance is dead with whistling noise coming from power supply.
1: Check for leaky BUT11AF line output transistor, replace and fix any dry joints in the line driver stage.
Appliance is dead with standby LED flashing after a few seconds.
1: Check line output transistor. 2: Check 15V zener diode D6613.
HT varies and sound intermittently goes to max.
1: Replace C2631 (22nF) at the base of standby switching transistor (Tr7631)
Dead, HT low, 9V rail at 5V. |
1: Line output transformerfaulty. |
|
HT goes high. |
1: R3627 (33K) goes high in value in the regulation stage. |
|
Dead, HT correct.
1: Several possibilities here. C2519 (150pF) at pin 26 of TDA8305 or the 12V zener (D6030) in the kick-start circuit associated with pin 11 could be faulty. Check D6523 (1N4148) in line driver start-up supply.
Low 5V to micro chip. |
1: D6644 (1N4148) in the power supply is faulty. |
|
Intermittent dead with HT line at 8V. |
1: D6613 (15V zener) in the power supply. |
|
Appliance comes on intermittently. |
|
|
1: Replace C2058 (22mF.100V) in the kick-start circuit associated with the TDA8305 chip.
Dead after 2 hours.
1:[HT present]. Replace D6523 (1N4148), TR7251 and TR7523 (both usually BC337) and change C2523 (6.8uF) to 68uF/63V. Any one of these components can cause this .
2:Check line scan coil connector for dry joints.
Failure of R3616, R3680, Tr7610 or D6610 in power supply.
1: In the event of failure of any of these components, all must be replaced. Do not connect any probe to the "Gate" of Tr7610, or it will be destroyed.
No power supply, blank screen only. |
1: Check C2044 (4mF). |
Dead. LED flashes after a few seconds.
1: Check line output transistor, if ok check D6613 (15V zener diode).
SOPS defective.
1: If one or more of following components are defective, replace all: R3616, R3618, TS7610 and D6610. It is important not to touch gate of TS7610 (mosfet) with any probe while checking for s as this could cause mosfet to become defective.
Set dead with no 95V output from the power supply.
1: The over-voltage thyristor fired when the ht reached 50V with the mains input fed via a variac. One of the sensing zener diodes, D6638 (BZX79-B36), in the thyristor's gate network was leaky.
Set dead with ht low at 10V.
1: The sound output chip was s/c. Also the BYX79C15 zener diode D6613 was leaky. For the power supply to start there must be 15V across this diode.
Set dead with ht low at 5V.
1: The set was stuck in the standby mode. Checks showed that the microcontroller chip's reset line was pulsing. Zener diode 6671 (BZX79-F4V3) was the cause.
No power supply start up in loaded condition (eg. with lamp).
1: Start up power supply in unloaded condition. This now supplies 95V. Now charge with lamp (e.g. 100W). Power supply should now function.
No output from the chopper power supply which uses a junction FET, whose gate and source are at 12V while 300V is present at the drain.
1: Check zener diode D6610 (BZX79C10). For tuning drift change the ZTK33B voltage stabiliser.
Set dead no output from the power supply.
Set dead no output from the power supply. 1: Check D6638 (BZX79C36) for S/C. It is one of the sensing zener diodes.
Set dead with just 5V on the 95V line. Standby LED is on but set won't start. 1: Check D6671 (BZX79-F4v3) zener diode.
Set dead. Line oscillator not working. |
1: Check 12V zener diode D6030 for O/C. |
Set dead, no HT supply.
1: Check zener diodes D6638/39/40 and thyristor THY6641 in the overvoltage protection circuit. D6638/39 are usally 36V types and D6640 30V but check in the relevant service manaul. THY6641 is type SF2D41.
Dead, output transistor s/c. |
1: Replace choke L5519 (3.3µH). |
||
Dead, no line oscillation. |
1: Check D6030 [12V zener] for o/c and C2044 (4µF) for s/c. |
||
Intermittently appliance is dead and remains in standby. |
1: Check C2631 (22nF). |
||
Appliance is dead or intermittent. |
1: [+9V is low]. Check C2523 (6.8µF). |
||
Random breakdown of line output transistor. |
1: Check Tr7521 and Tr7523. |
||
Unregulated power supply. Pulsating picture and surging sound. |
1: Replace 2523. |
|
No quick start pulse. |
1: 3680 slightly high. |
|
No 9V. |
1: 3680 slightly high. |
|
No regulation. |
1: 3680 slightly high, ie. 8.2ohms. |
|
No SOP supply. EHT OK. [refer to service info SI 009/90].
1: Replace IC7020. 2: Replace 2631. 3: Replace 8.8MHz crystal.
Quick hiccup.
1:7785 memory IC is faulty.
2:2102 has the wrong value.A 0.33µF/100V has been fitted, change to 3.3µF/50V.
Only 90V, B+, hiccups 112V=90V. Picture narrows. |
1: Replace 6614 due to S/C. |
Power supply squealing. |
1: Check 8.8Mhz crystal. |
Slow hiccup
1: Dry joint, S7020 and power supply. 2: 5V line down to 3.5V. 7673/6671 leaky.
Dead power supply after fitting the SBC7020 kit.
1: Check that a solder bridge has not been created between the anode of 6670 and one end of 6669. Great care must be taken when fitting SMDs, they are easily damaged by heat and easy to create solder bridges causing S/C.
Trips intermittently at switch on.
1: Check D6638, D6639, and D6640. All three should be 36V.
No switch on. Low noise on sound.
1: Choke 5524 O/C. 2: If switches on after a while, replace C2523 (6.8uF).
Appliance is dead, low level buzz from loudspeaker. |
1: [9V low at 5.5V]. Check choke L5524 for o/c. |
|
Appliance is dead, slight grunting noise. |
|
1: Check L5524 (1.5mH). |
Trips intermittently at switch on. |
1: Check D6638, D6639, and D6640. All three should be 36V. |
|
No switch on. Low noise on sound.
1: Choke 5524 O/C. 2: If switches on after a while, replace C2523 (6.8uF).
Appliance is dead, low level buzz from loudspeaker. 1: [9V low at 5.5V]. Check choke L5524 for o/c.
No start up. 1: Replace electrolytic capacitor (6.8µF/50V) near the high voltage transformer. 2: [No short measured at line transistor]. Check audio amplifier TDA7052.
Trips at switch on.
1: Check overvoltage sensing zener diodes D6638, D6639 and D6640; if OK check R3100 (1R).
Dead, just buzzing. |
1: [No feed to TR7521 and TR7523]. Check L5524 for O/C. |
|
Voltage +92,5 is only 2V. |
C2523 6,8uF/40V. Replace with 68uF. |
|
KORISNE INFORMACIJE
U743 tuner replacement.
The U743 UHF tuner has been replaced by the U943. In all applications it is a direct replacement. Where the substitution was made during production some components, being no longer required, were deleted at the same time.
This means that in some chassis the tuners are not reverse compatible ie. a U743 cannot be fitted in place of a U943 without first refitting components concerned with the +12V supply to pin 10 of the U743 tuner. The list of changes are as follows:
Old tuner: U743-Phono 482221010339 |
New tuner: U943-Phono 482221010452 |
|
Removed: C2004 |
Connector 9087 |
Connector/coil 9510/5000. |
Up and protection with hotel mode.
Note: The existing code numbers for the up are being recoded to code number 4822 310 31947 (up and protection) without hotelmode. If it happens that a customer especially wants the hotelmode this is available under 4822 310 319822 (up and protection).
/V models always have hotel mode.
Note: /R and /B models may appear with or without hotel mode. Appliances with a /V- behind the model number have always had the hotel mode feature (since production). The only difference concerns the microprocessor, for code numbers see additional information under 4822 310 31982.
New hotel mode.
Note: A new hotel mode has been introduced since production code PM09 and ZB09. This feature is not mentioned in the instruction manual.
Activate: select pr. 38, set at desired max. vol. press the mode/install button on the local control and, at the same time, the sleep timer or OSD on the RC until H+ appears (after approx. 3 sec.). After switching to stand by or off position, the mode is active.
De-activate: As above, except adjusting max. vol., H- appears. Microprocessors new hotel mode.
Note: Microprocessors new hotel mode code numbers.
-App. with 8 local control buttons: TMP47C434N-R221 4822 209 32192 -App. with 3 local control buttons: TMP47C434N-3142 4822 209 32118 Introduced since production code PM05 and ZB05 (not in SV.. app.)
(Before operation see instructions "New hotelmode".)
Audio demodulator reels.
Only in appliances with the SV serial number, during manufacturing the audio modulator reels (position 5034 and 5045) were replaced : 5034= 4822-157-63742, 5045= 4822-157-63238.
Reset circuit.
In appliances with ZB or PM serial number the reset circuit was changed: 2782: new 4u7 4822-124-41577 3741: new 10k 4822-116-52233 9025: plug in bridge has been removed.
Reason for insertion: adaptation for appliances which could not be switched on with a lower mains voltage.
Service manual correction.
There are no coils and no connection between pin 5 and pin 1 of the line transformer (5530). The coils are between pin 10 and pin 1 of the transformer.
UHF tuner U743
With all "Only UHF" appliances (-/05) tuner U743 (4822 210 10339) was replaced by a U943/Phono (4822 210 10454).
New microprocessor IC7700.
A new microprocessor without "Hotel mode" was inserted. 7700= TMP47C434N-3537 (4822 310 31947). For appliances with SV serial number: Insertion calender week 9140
(9142 for LFL-manufacturing);
For appliances with PM/ZB serial number: Insertion calender week 9150. This microprocessor is supplied including the screen.
Tuner UV617/PH
Tuner UV617/PH was replaced by the UV917E/Phono. Also replaced were the following components: In appliances with SV-serial number:
a)3000: Resistor 5M5 ohm (soldered in between pin 22 of IC7020 and pin 11 of the tuner). Adjusted to avoid "picture foldover" when switching channels. Fitted Calender week 9129.
b)3704: Replaced by a 100R to avoid minimum tuning voltage. Fitted: Calender week 9126.
In appliances with ZB or PM serial number:
a) 3065: Replaced by 6M8 ohm (soldered in between pin 22 of IC7020 and pin 11 of the tuner). Adjusted to avoid "picture foldover" when switching over channels. Fitted in Calender week 9129.
Loading...