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NEI CE25 Notes - COLOUR DECODER

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NEI CE25 Notes

Introduction

     There are Three main versions of this Chassis,version One being made by Clarivox in Spain, this is easily identified by being a biscuit coloured board material, and being single sided.

     Version two is made by Vestel in Turkey and can be identified by having a green coloured board material and being double sided copper.

     Version Three was introduced in Spring 94 and is similar to the Vestel chassis, however the Audio output stage uses a different IC and its layout is altered in the audio stage.

  Version Three also has facilities for adaptation to include a Satellite receiver,Single Scart and Mono Audio.

AUDIO STAGES

 (Nicam & Zweiton seperate sections).

General Description.

 I.F Stages.(Nicam UK Version). Intercarrier sound has two paths.The stereo path is via a Quasi Parallel Saw Filter and Ic002,to the Nicam Module. The mono path is also from IC002 but is routed to IC114 (U829). The outputs from the Nicam and Mono stages are selected by IC115 (TDA8425) from the I2C bus, which also controls volume,tone and other audio functions.

 The output from IC115 is fed to the Audio Output stages via a Mute Module on versions 1 & 2, Version 3 mute components are on the main pcb and IC116.

 The Audio Switch Module routes audio signals to and from the Scart sockets.

NO MONO SOUND (Stereo ok).

R517 (10K) on Nicam panel o/c.

NO SOUND.

        Check +26V supply from PSU to IC116,if missing check R133 0R1 Fusible,D108 o/c or Pcb Track from Psu around edge of main board.   Trace Audio with Oscilloscope from Pins 10,11 & 12 of Nicam Module, to pins 18,20 of IC115. From pins 9 & 13 of IC115 to pins 4 & 6 of Mute module.    From pins 1 & 2 of mute module to pins 1 & 5 of IC116.  If the mute module is active ie Muting then check Ident pulse to Pin 29 of IC117,this will make Pin 2 high.    Also check Sandcastle pulse on Fast Text module IC701 Pin 13.   On Version 3 TR135 may be s/c.     If no Audio from IC115 check C237 leaky.

NO SOUND WHEN AV SELECTED.

        IC115 Faulty.

INTERMITTENT MUTING.

         This could happen on early chassis and may be due to Pin12 on IC117 floating,this should be tied down to ground.

SOUND PLOP AT POWER OFF.(Version 3 Only)(Ver 1 has no anti-plop circuit).

        TR136 faulty or R375 o/c,or +16v missing from track on topside. D139 / D140 S/c.  Check other components in circuit.

IC116 GETTING HOT (or failing for no obvious reason ie shorted speaker leads etc).Also RF Oscillation on output pins.

 C282 o/c,

IC116 GETTING HOT (Rf oscillation on one output pin).

 R256 or R257 o/c, C286 or C287 o/c.

DISTORTED SOUND (on Pal I Mono signals).

 L107 off tune or C297 faulty.

DISTORTED SOUND (on Pal I Mono signals when Text is selected).

 CF100 faulty.

MONO AUDIO LOW LEVEL.(Distorted Nicam).

 Pins 2 & 3 of audio switch module may be shorted.

MONO AUDIO MISSING.

  TR111 faulty, R248 (2K2) O/C. Check intercarrier IF input.  

     

  COLOUR DECODER.

 (See also Luma Path section 9).

General Description.

    This section is a more complex system than earlier decoder designs in that it utilises a digital delay system rather than passive delay lines.    Auto greyscale is also used to minimise colour drift as the Tv ages.    IC109 is the Luma delay stage and chroma filtering.   IC113 is a Chroma delay stage. IC111 is a single chip decoder and matrix stages.

NO PICTURE.No OSD (Raster if A1 voltage increased).

        IC111 faulty.In most cases this failure is caused by a FLASHOVER from the Line Output Transformer to Chassis,especially if the LOPT has a date code RB6. Pin 10 IC117 (Dark Current) or Pin 4 Conn 600 o/c. C256 1uF Pin 11 IC117 leaky.  IC111 Pin 24 BEAM LIMITING should be 4.5v nominal, if lower ie 4.0v check R150,D134,R333 and C299.

       On early chassis ie Clarivox, check earth connections to the Jungle module, this can break rather easily if the module is handled roughly.

WEAK PICTURE.NO SYNC. NO SOUND.

        XL102 (4.43Mhz) faulty, No 2FC output from IC111 Pin 8 to IC109 Luma Delay, thus no output from Pin 4 & Pin 6 IC109.

UNCONTROLLABLE BRIGHTNESS.

         IC117 Pin 5 o/C or Filter network R317,R206 faulty.

ANY PRIMARY COLOUR MISSING.

         No output from relavent pin IC117, check relavent de-

coupling cap C252,C253,C257 Leaky. 

MONOCHROME PICTURE and RAGGY DISPLAY

   C202 100nF leaky.

CHROMA UNSTABLE ON TRANSITIONS

     Check R-Y/B-Y output of IC111 Pins 26/27 for clean transitions,if yes check R-Y/B-Y inputs pins 21/22,if oscillation occurs R253 o/c or C243 o/c.   

NO COLOUR.

R337 o/c. IC113 faulty.

WIDE GREEN LINE AT L/H SIDE,NO PICTURE, NO OSD.

C225 (100N) O/C.

NO PICTURE WHEN SW100 SHVS SWITCH OPERATED.

D138 S/C.

COLOUR WILL NOT MUTE VIA SCART 1 WHEN SW100 SVHS SWITCH OPERATED.

IF pin 5 IC109 goes high IC109 faulty. 

FAINT PICTURE & NO SYNC WHEN SW100 SVHS SWITCH OPERATED.

R230 (56K) Low in value.

NEGATIVE PICTURE.

RV004 1K0 O/C or wrong value in Jungle module.

NOISY CHROMA

May be caused by the Focus wire connection at the LOPT not seated

correctly.

MAGENTA AND CYAN ONLY (Chroma out and in to IC111 ok).

Internal problem in IC111

 

For OSD Faults see section 9.

                                                     CRT BASE

General Description.

     IC601 is a triple Video Output Driver which incorporates Auto grey scale circuits.   To finely balance the drives,unusually, preset resistors are added. IT IS IMPORTANT THAT IF A CRT IS CHANGED THE CORRECT SERIES HEATER RESISTOR IS FITTED.

UNCONTROLLABLE BRIGHTNESS (Max Beam Current).

 No Ht caused by R612 O/c, or R137 (10R) Fusible on main PCB.

WASHED OUT PICTURES (Slow to Warm up)

This is usually after the Crt has been changed or from early production, where the Heater series resistor R614 is the incorrect value. See the manual for the correct resistor value.

 

ONE PRIMARY COLOUR MISSING.

 If the drive from the IC111 is missing,the fault could be due to feedback resistor from the feedback pin on IC 601 being o/c, this upsets the Dark current signal and cuts off the drive.

COLOURED TINT (any one primary colour).

IC109 (TEA5101A) faulty.

COLOURED FLASHING LINES.

IC109 (TEA5101A) faulty.

STRIATIONS.

C610 (10Nf) A1 Screen decoupling O/C.

NO RASTER (Raster if A1 Screen is increased).

+12V supply missing check R612 (10R) fusible o/c.

UNCONTROLLABLE WHITE RASTER (With flyback lines).

+200V HT missing check R625 (100R), or R137 (10R) D121 Main pcb.

E/W MODULATOR

(Width control also effects Parabolic W/F to some extent.)

OVERSCAN (Width control works but not fully).  

        R371 1R0 Fusible o/c. Side effect causes T702 BU508 to get hot and fail

OVER SCAN ( Controls no effect)

        Check voltage on IC107 pin 7 if missing C160 s/c or R220 o/c. Check R154 pin 6 + supply, D114 o/c, R368 (2R2) o/c,R371 (1R0) o/c, IC107 (TDA8145) faulty.    If voltage on pin 8 2.5vdc max then C159 (3n3)O/C.

 

OVERSCAN (No Control Functions R317 1R0 fused).

        D117 S/C.

UNDERSCAN with foldover.(No Control Functions).

        D116 O/C may cause R154 to fail also IC107. R181 o/c.

UNDERSCAN no foldover (Controls partial effect).

        D109 s/c (pin 8 IC107 9.5V min).

TOPHALF OF SCAN OK, BOTTOM HALF BOWED OUT.(Controls work                                 partially).

        IC107 faulty.

WIDTH CONTROL AND PINCUSHION CONTROLS PARTIAL EFFECT (Ringing on

Verticals)

        C134 O/C

PINCUSHION CONTROL ACTS AS A WIDTH CONTROL (Width control ok)

Check pin 1 IC107 for vertical ramp, if missing, link from PL102 or track O/C.

Waveform at pin 2 should be same size as other side of R175.

HORIZONTAL OUTPUT.

 General Description.

     This is a typical Line output stage generating EHT, Focus and A1/G1/ Screen control voltages, Crt heater and Video Ht voltages, Vertical output stage supply voltage, and a +5v voltage for Teletext and other functions.   D116 & D117 form part of the line scan correction circuit controlled from the E/W modulator (see section 4).

     

EXCESSIVE WIDTH (See E/W MODULATOR for other faults).

        D117 S/C .  Low Eht.C134 faulty.

NO RASTER. (TR128 S/C).

        C134 O/C. Causes Excessive pulse voltage, may also damage IC107. TX102 s/c turns. Low drive caused by driver stage faulty or R123 high.  R174 fusible o/c or high. TR105/106 and assoc components faulty.

NO LINE DRIVE

        D123 S/C, or wrong way round.  Jungle module earths o/c.

STRIATIONS OR LINE RINGING.

        R135 o/c, Damping network on NOKIA D/Yolk o/c. C610 (10Nf) on Crt base o/c. 

        LK174 Analog earth link adj to DST/C130 high res or dry joint.

RAGGY VERTICALS or WAVY VERTICALS

        R022/C017 in Jungle Module faulty.

        LK174 Analog earth link adj to DST/C130 high res or dry joint.

LINE COLLAPSE ( possibly arking or squealing noise).

        L116 shorting to D121, change D121 and C140.

NON LINEAR SCAN ON R/H SIDE (TR128 BU508 getting hot and may be destroyed).

        TR105 (BC337) o/c.

NON LINEAR SCAN (TR128 temp ok).

        L104 fitted wrong way round.

LINE OUTPUT TRANSISTOR S/C (after 5 mins)

        Line drive voltage low, not turning TR128 (BU508A) off fast enough, usually TR105 (BC337) o/c, poss TR106 (JC501).    Line drive voltage low, (no neg pulses) Track to R121/C312/R122 broken, Why it affects drive voltage is unclear.

        Low dive or wrong frequency,Jungle module earth broken,usually on early Clarivox Pcb.

     R371 1R0 fusible O/C, Side effect of no E/W Correction

LINE OUTPUT TRANSISTOR S/C IMMEDIATELY

D116/D117 S/C, C132 (27n)O/C , C131 (9N1) O/c

PICTURE BREATHING (Changes of width due to Beam current levels, also non linear line scan).

C132 (27N) lower half of E/W modulator caps O/C

                                                       JUNGLE MODULE

General description.

 As the name implies this module does many functions including:- Video If,Vertical & Horizontal oscillators, sync seperator and Quasi-parallel sound circuit.   For more detail see the service manual.

 

RAGGY VERTICALS.

           Poor Solder joint on topside of PCB to Jungle Module. R022 o/c, C017 o/c.

 

NO HORIZONTAL SHIFT.

           R016 to Pin 31 o/c.

PICTURE SHIFTED 10 Cm TO LEFT.

           D734 s/c.

PATTERNING ON VIDEO. (Appears as instability).

  C012 o/c (vertical feedback decoupling).

VIDEO MUTED by IC117. (Distorted Sandcastle).

           IC001 (TDA4504) faulty.

NEGATIVE PICTURE. (Excessive video (2V pp) on pin 6)

           RV004 (1K0) High or o/c.

NEGATIVE PICTURE. (level ok)

           Pin 32 IC001 high or link 107 o/c

NO PICTURE   NO OSD ( Raster if A1 increased).

  On early chassis ie Clarivox check the earth connections to the Jungle module, this can be rather fragile on Single sided pcb's.

Repair using tinned copper wire to strengthen joints.

WEAK PICTURE

R010 (2K2) o/c

VERTICAL ROLL (Local feeder Relay Station)AND TV GAMES SUCH AS SEGA and NINTENDO

Although the video level measured ok, raise the value of RO13 (1K0) to 1K5.

 Low Video back from Text IC110 Check R211 (1K2) may be high if ok going in.

VERTICAL ROLL (Picture cogging)

C009 (10u) O/C causes AGC to not act correctly.

TUNING DRIFT

C22 (2N7) leaky

TOP OF PICTURE PULLING ON VIDEO PLAYBACK.

Change the following components   R22 to 1K5, R23 to  82K, C17 to 4u7, C21 to 68n.

VERTICAL NOISE BARS (Approx 5) across crt.  (Picture very unstable). ( Noise bars also without aerial connection).

Change tuner.  (Disconnect I.F output and retest).

                                         

 KEY PAD/IR MODULE.

 Version 3 only.

         Although intended for version 3 it can be retrofitted to earlier versions if a new cabinet front and connector C950, and headphone/IR panel is added.

KEYPAD WILL NOT FUNCTION (1Key/allkeys).

   This may be due to the connector from the membrane PL955 or the membrane its self, to test s/c pins 1 & 7 on Conn 950, this should make the tv step up 1 channel. If suspect change the membrane carefully.    On large 28' screen tv's the Crt must be

removed to refit the Pcb, due to the short tail on the membrane.



EITHER LED NOT WORKING OR NOT CORRECTLY

    GREEN, check Nicam is ok if yes connect another Led to pin 12 of conn 950, if ok remove pcb carefully.

    RED. Check assoc components after checking Pin 10 of conn 950 =0v. R955 across TR951 causes led to shine dimly when tv is working normally, when in stand-by R954 causes TR951 to conduct fully ie bright led.

NO OUTPUT FROM EITHER SPEAKER

   Conn SK951 contacts faulty, C952/953 s/c.

NO OUTPUT TO ONE OR BOTH H/PHONES

   R956/957/958/959 o/c or faulty SK951.

IMPORTANT !!!!!!

C952/953 & R960 must be fitted to protect the Microcontroller if either Conn 951/954 become o/c.Otherwise large voltages can be generated via the speaker wires running across the Crt.   

                                                 LUMA PATH.

 See also COLOUR DECODER.

General Description.

   The composite video leaves the Jungle Module pin 6, goes to pin 16 IC109, the signal leaves IC109 via two routes.   Pin 4 (delay) goes to TR120/TR121 and is also split, one in phase,one anti-phase, the in phase Video goes to pin 27 IC110 Text Generator for text sync.   The sync signal exits IC110 pin 1 and returns to the Jungle Module to pin 13.

  The Anti-phase video goes to TR122 and then to AV1 pin 19.   If it is a non-text tv the video also is taken from here to pin 13 of the Jungle for Sync.       The other Luma path from IC109 pin 6 goes to IC111 pin 25.

NO LUMA (NO OSD),(GENERAL).

         Check SANDCASTLE either pin 15 of Jungle Module,IC111 Pin 8,or IC113 Pin 14. If distorted or wrong amplitude check pulse at junction of R151,C157 and R152/C155 this should be a 20vPP pulse. If wrong check C155 Leaky. If still faulty disconnect IC111 & IC113, and check junction R173/R151 & C157 this should have a pulse of 300v p/p. R173 High causes a droop on the trailing edge of the top pulse, R121 or R151 High causes the bottom level to be distorted, if pin 8 of IC111 is lifted and the sandcastle pulse modifies, but is not clean and square check R121/R151.   Check +5V supply to IC103 if missing R139 o/c or D122 leaky.

  On early chassis ie Clarivox,the Jungle module earth tabs may become disconnected, (see section 6).   Check R612 (10R) on Crt base. No +12V to IC601 

NO LUMA (OSD OK)

     Check Pin 2 of the Jungle Module this should be Low for Tv mode,if high the IC001 switches to AV mode.   The control for this pin is from the Audio Switch module pin 16.  R286 o/c causes pin 9 IC111 to float to 0.9V. Check pin 36 (IC117) Low for TV, High

for Av.       Check Pin 15 of the Audio switch module, if not 0V ie AV2 mode or between levels this will inhibit video from pin 6 IC109.

     Check 2FC from pin 28 IC 111 if missing this will stop Luma delay IC109 from outputting Luma from pin 6, causes of no 2FC are C203 o/c XL102 faulty,(amplitude 400m/v pin 12 IC109).

NO RASTER UNTIL A1 INCREASED, (then A1 difficult to set, as brightness oscillates).

IC111 (TDA3591) Faulty

VERY WEAK LUMA POOR SYNC (OSD OK).

     R250 (56K) o/c or high. R010 (2K2) jungle module o/c.

    TR120 leaky collector/emitter.

     C295 (10u) leaky, shunts luma from pins 4 & 6 of IC109.

     C210 (10u) leaky, shunts luma thus sync source to IC110

NO LUMA FROM OR TO ANY PARTICULAR PIN ON SCART SOCKETS.

 Obviously check signal path to the particular pin in question.

NEGATIVE PICTURE.

  RV004 o/c or High (Jungle Module).

INTERFERENCE ON PICTURE AS VOLUME IS INCREASED.

  Lead PL107,PL108 trapped in Crt rimband.

MICROCONTROLLER

General Description.

This is a dedicated Microcontroller from the PCA84C640 range, but its functions are

controlled by a Mask Program designed soley for NEI. There have been 4 Software versions to date.   The purpose of the Microcontroller is to control all Digital (Text Tuning and Keypanel) functions and all Analog (Volume,Saturation,Contrast Etc) functions via the I2C bus system.

   At power on the reset cycle starts and the Controller interrogates the Set-up conditions,Key panel,and periferal sections ie Text,Nicam etc via the I2C bus. When the controller is activated either by Remote Control or versions with the keypadthe I2C bus becomes fully operational. See manual for a full description.

WILL NOT COME OUT OF STANDBY (Red Led Stays On half brightness).

     If Pin 41 (SYBCONT) stays low, check XL103, this cannot be done directly due to Scope probe capacitance loading the oscillator, check the Strobe Pins P13©P19, if there is no clocking change XL103.

     If clock pulses are on P13©P19 but P41 stays low, disconnect all devices on the I2C bus except IC112 (Memory) & R296/297 pullSup resistors.    IMPORTANT  Make sure amplitude of I2C Bus is correct ie 5vPP. If the Micro now comes out of Stand-by check

each of the modules on the I2C bus, not forgetting IC115 analog control. Reset components C263/R295 or their supply may be faulty. Check connections of PL950 on Versions 1 & 2, if the pads are broken the TV will not operate.

COMES OUT OF STANDBY BUT NO FUNCTIONS,NO RASTER,AND WILL NOTRETURN TO STANDBY.

     This is typical of the I2C buss crashing and disconnecting all the items on the buss will pinpoint this, however if the ground from the PSU to main ground is o/c (Link 172 under C130)this will give the same symptom.

WILL NOT GO TO STANDBY. (Raster and Audio active but Standby led lit).

    TR130 (BD234) s/c in psu.

WILL NOT TUNE (Osd working Ok).

     Check the Tuning Voltage Line (TV),this should swing between 0-28V DC depending upon OSD display position. If there is no voltage, check Pin 1  for a 5vPP Squarewave with a varying mark/space ratio, if the output of pin 1 is ok suspect TR126, associated components and + 33V supply.    If the output from pin 41

is not ok change IC117. If the TV is a Multi-band type ie B1-B3/UHF, check that just one of the band switch pins is active, if more than one pin is high this will stop the tuner from working correctly, check TR108/109/110/112/113/114 and associated components.

WILL TUNE (Will not store OSD OK).

     Check R320, C266  IC112.

WHEN TUNING WILL NOT STOP ON SIGNALS (OSD OK). (to stop tuning sweep, press Fine Tune on handset this will enable the video signal to be tuned, then traced more easily).

     Check Pin 29 Ident, this should go high when a signal is present,if not check Pin 14 IC001 (Jungle module) R011 (15K) may be o/c.

     Check video to Pin 27 IC110 if missing R217 o/c.

     Check adjustment to RV001 (Horiz Freq Jungle module).

MICROCONTROLLER Cont..

WILL NOT STORE ANALOG LEVELS IN PP MODE.

     Check IC112 as the Analog and Tuning memory are in different segments.

NO OSD DISPLAY (Tv functions normally).

     1. Check sync inputs to Pins 27/28 both must be present.

     2. Check Outputs Pins 22/23/24/25 each pin will depend upon the colour used on the OSD, Pin 25 (blanking) will always be active .

OSD WRONG COLOURS OR WRONG LEVELS.(Text Ok).

     Check Pins 22/23/24 for +5v pp levels and via TR117/118 & 123 to Colour decoder IC111 Pins 14/16/18.

OSD WRONG COLOURS OR WRONG LEVELS. (Text Levels incorrect).

     Check IC111,C255/258/259 & R279/281/283.

OSD SHIFTED HORIZONTALLY,SQUASHED or ELONGATED.

     If IC117 has been changed check value of C260,(see manual for value). If IC117 has not been changed check R286 & C260.

NO OSD. All functions ok.

     D133 s/c.

ANALOG FUNCTIONS INCORRECT.

     If one control ie Brightness has an effect on other functions, check the +5v supply to R315/316/317.

     If one function is not working check relavent component network & IC111.

AV SWITCHING INCORRECT.

     Pin 36 is Low for TV, High for AV. 

     Pin 34 is Low for TV/AV, High for AV2.

If ok check TR115/116 and assoc components,if Ok check outputs from Audio Switch module.

DEFAULTS TO AV1 AT POWER ON.

     Pin 8 circuit active, pin 12 must be 0v. Check earthing on Fast Text PCB or Link to Controller o/c allowing pin to float.

NO REMOTE FUNCTIONS.

     Check IC195/ R296.

 

  NICAM MODULE.

   General Description.

      The Nicam decoder as used in the Uk is contained in one module and is connected to the Microcontroller via the I2C bus.   For a detailed description see the service manual.

NO NICAM (Led or Osd shows no Nicam signal).

   Carrier PLL not locked, or Data PLL not locked, see manual for alignment details.

NO NICAM (Led or Osd showing nothing wrong).

   Check audio outputs at pins 6 & 8 of IC502, if no output check IC501/502 , + Supplies and associated components. If audio is on pins 6 & 8 trace through IC503/505 and assoc components.

NICAM SLOWLY OSCILLATING IE PLOPPING.

    Check alignment of C544 (data PLL) and adjust as per manual.

 

NICAM DROPOUT.(Versions 1 & 2 only).

   L503/504 may be wrong value, should be 1mH.

        

    POWER SUPPLY

     General description.

  The Power Supply is a modern conventional Switch Mode type,however the regulation is controlled from the secondary side and fed back via an Opto Coupler IC101.  Current limit is set by R102, 0R22 and is a Fusible type.

 NO OUTPUT (IC100, TR100, IC101, R102, R109 may be destroyed).

  This catastrophic failure is due to R102 failing or being out of tolerance, unfortunately it sometimes causes TR100 to break-down its Base/Collector junction and damages the following:- IC100, TR100, IC101, R102, R109 (13K7), C107, C108, D104.

   It is also wise to change C109 from 2u2 to 3u3, and D104 from a 300mw to a 1W3.

    Another cause of multi component failure is C105 1N8 dry joint or leaky or R328 o/c.

NO OUTPUT (TR100) FAILS IMMEDIATELY.

R107 (1K5) going low  R112 (240K) going high, C122 (22U) low value

NO OUTPUT( as above but TR100 gets very hot (100 degC) before failing).

L100 1u8 dry joint or O/c.  Normal heatsink temp measured on case of TR100 approx 50/60 deg C.

     

 NO OUTPUT (No major failures).

    R101 o/c,R103 o/c,R112 0/c,R115 o/c,R116 o/c,C110 o/c, C111 o/c,C112 s/c,C122 o/c,IC101 pins 3&4 s/c,D104,o/c,D106 o/c,

 NO OUTPUT (TRIPPING).

    Remove all components from secondary of Tr100 Pins 4,6,8. TR128 s/c.   Also check R109 (13K),R111 5K6 high.  If D104 (5V1) zener is 300 m/W change to BZX85 type.

Pin 4 Ground track o/c. (ESPECIALLY AFTER PSU BLOWUP).

LOW HT (64V nominal).

  Check ripple of voltage Pin 5 IC100 must be millivolts, if higher check C110 o/c.

HIGH HT  180V (No control).

 IC101 faulty, no feedback to IC101 or IC100, TR102/103/104 and assoc components, C125 s/c,R124/125 (39K0 o/c. IF VOLTAGE OF C114 (160V) IS EXCEEDED THEN CHANGE C114.

HT LOW (+139v) NO RASTER (PSU GROUND ©7V relative to SIGNAL GROUND). Also I2C Bus appears to fail ie TV looks ok in standby but then no control after coming out of standby.

   Earth link TOP to earth link BOTTOM o/c. LK172 sited under C130.

HT OK ON STANDBY BUT DROPS AT POWER UP (This may be from 145v to 120v depending upon current requirement).

    R112 240K o/c.

WILL NOT GO TO STANDBY. (Raster and Audio active but Standby led lit).

   TR130 (BD234) s/c.

   

NOISY TRANSFORMER (high pitch squealing).

R117 (4K7) o/c, C113 (47N) o/c.

POWER CONSUMPTION

                 +16v/+12v 40m/a quiescent,400m/a typical.

                 +26v       70m/a quiescent,1.13A max volume

                 +154v     300m/a nominal,400m/a max beam

 

TELETEXT

    General Description.

           The basic Teletext system is a 4 chip solution including a Co-Processor on a sub-panel to determine the Text features ie Tops Text, Fast Text etc. The Text system will not

operate without the Sub-panel.  A full description is included in the service manual.

NO TEXT (No Headers or page numbers).

 XL701 o/c on Fast Text panel.

NO TEXT (Header Ok & Fast/Tops Boxes ok).

    Check VCS pulse IC110 pin 25/IC105, C186 (22nf) o/c.

NO TEXT (Page number only).

    XL101, C189 faulty, L105 (15uH) o/c, C190 (27pf) o/c,     

 R200 (6K8) o/c.

CORRUPT TEXT. (Headers and Page Nos ok).

    C184 leaky.

    C184 (1n0) o/c.

    C185 (470pf) o/c.

    C187 (270pf) o/c.

    C188 (100pf) o/c.

    R201 (68K) 0/c.

     TUNER & BANDSWITCHING

      General Description.

        In the UK the Tuner is of a UHF only type,and Bandswitching components are eliminated, however in certain markets ie Eire and Europe the bandswitching components are fitted, those being TR108 © TR114 and assoc components, a multi-band tuner fitted.

ONE BAND NOT SELECTING.

   Check components of relavent Band switch

NOISY PICTURE (no agc control effect).

 C226 leaky or R274 o/c.

 

NOISY PICTURE (agc control ok).

 Tuner low gain.       

TUNER DRIFT

C22 (2N7) in Jungle module leaky. TR126 (2N3904) leaky or low gain. C272 (100p) noisy.  C199, C271 (100N) leaky.

VERTICAL NOISE BARS (approx 5) across crt.  see jungle module page 8

VERTICAL OUTPUT

  General Description

          The Vertical output stage is devided into two parts, the Oscillator and drive, located in the Jungle module, and the output stage IC106.  Active feedback is connected between the two stages.

FULL COLLAPSE

 R140 o/c. May be caused by IC107 (TDA8145) going S/c.  If O/p IC fails, disconnect Pin5, if then ok, IC107 faulty.

NEAR FULL COLLAPSE

 D113 (ZTK33) low voltage.

LINE PAIRING AT TOP OF SCREEN

 Instability caused by R148 o/c.

HEIGHT JITTER.

  C013 (220nf) R027 (1M3) in Jungle module.

FRAME CRAMPING (Bottom half ok, Top half severely cramped but no

fold©over).

   R019 (43K) (Jungle module) goes high to 80K approx.

   R018 (15K) (Jungle module) goes high.

    SCART SOCKETS

    General description.

          There are two Scart sockets,both having different features. Scart 1,Composite video in and out, Stereo Audio in and out,SVHS input and Pin 8 Switching. Scart 2, Composite video in and out, Mono Audio out, Stereo Audio in, RGB Inputs, Pin 8

switching, Fast blanking input.

NO VIDEO INPUT AV2.

  TR904 (Av Switch module) not switching.

NO AUDIO OUTPUT AV1 pins 1 & 3.

  Components on Audio Switch module relative to channel affected.

AV1 PIN 8 SWITCH FAULT.

  TP106 Circuit on Fast/Tops Text module faulty.

AV2 PIN 8 SWITCH FAULT

  TP104 Circuit on Fast/ Tops Text module faulty.

NO HORIZONTAL PICTURE SHIFT ON RGB.

  All assoc components on Fast/Tops Text module.

     

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