20GR105265B / PHILIPS [TV 51 (47/48) cm picture]

• No tuning.
• Green screen with flyback line. No picture. OSD OK.
• Stops at start up. (extract of circuit diagram attached)
• Vertical collapse. (+ extract of circuit diagram)
• The switched-mode power supply cannot be loaded.
• Sound varies with picture content. (PHILIPS - 20GR105265B information)
• No colour.
• Dead, very slight whistle from PSU.
• Does not start. Slight buzzing in loudspeaker.
• Tuning drifts. (picture attached)
• Stuck in standby. (+ extract of circuit diagram)
• No functions. when cold.
• No OSD. Picture OK .
• No tuning or on screen tuning display.
• Programming unoperational. Limited sound adjustment possible.
• Set comes on in store lock mode. (extract of circuit diagram attached)
• To remove store/lock.
• Print with linearity coil pos. 5800.
• No tuning. only on certain channels. (PHILIPS - 20GR105265B information)
• Does not switch on, standby LED OK.
• No voltage from PSU. (+ extract of circuit diagram)
• No power supply start up in loaded condition (eg. with lamp).
• Blank raster. OSD OK .
• No functions. Hum in loudspeaker. No LED lit.
• New infra red receiver.
• Control micro processors.
• Line tearing and rope effect.
• No picture. TXT OK . (with circuit diagram extract)
• Line tearing. on lower half screen. (with circuit diagram extract) (PHILIPS - 20GR105265B information)
• Very slight vertical foldover with interferences similar to EHT arcing, especially on very white scenes.
• Memory content dropout at positions 4 and 5.
• No line output stage. (extract of circuit diagram attached)
• Whistle.
• Control panel cover.
• Wavy picture. on the right.
• Intermittent audio and picture. (+ extract of circuit diagram)
• PSU switches off with load at U95V. (part of circuit diagram displayed)
• No colour.
• Display goes to F1 a few seconds after switching the set on.
• Error messages indicated by front display flashing. (+ extract of circuit diagram)
• 6613 type change. (picture attached)
• Field foldover at switch on from cold. Effect disappears when appliance warms up. (part of circuit diagram displayed)
• No functions. Standby LED flashes. Relay switches to ON.
• How to de-activate volume limiter. (20GR105265B PHILIPS repair tip)
• No tuning. Impossible to change analog control adjustments (brightness, sound, etc.). (extract of circuit diagram attached)
• Vertical size varies. intermittently.
• The TV does not stop during the tuning phase.
• Unable to retune set or set analogue levels. Store-lock option may be on "Hotel mode".
• Focus adjustment.
• Dead. Low frequency noise on sound.
• Picture is mostly green with flyback lines after 10 secs from switch on. (20GR105265B tips)
• Becomes defective immediately after switch on.
• Frame has shifted sideways. Appliance whistles and does not oscillate correctly. (+ extract of circuit diagram)
• No sound. Picture OK. After a short time TV stops. High frequency noise from PSU. (part of circuit diagram displayed)
• Green picture after few hours, intermittently fault disappears for short while when switching from a station to another. Strange characters in OSD.
• No colour.
• Green screen and at other times no tuning. (extract of circuit diagram attached)
• Searches for channels continuously. (extract of circuit diagram attached)
• Picture is faint with hanover bars. (part of circuit diagram displayed)
• Stations won't change. Picture and sound OK. Other functions OK.
• Sound varies with picture content.
• Dead. Only standby-LED works. Responds to TURN ON command, but no image and no sound.
• Green picture.
• Volume can't be tuned down. No tuning with RC. (with circuit diagram extract)
• Lines on picture after approx one hour. It consists of a band of bright white lines about two inches wide. (+ extract of circuit diagram) (20GR105265B tip from PHILIPS)
• Store lock on the appliance.
• Poor synchronisation. (with circuit diagram extract)
• New IR receiver.
• PSU peeps +95 is ca 0,8v
• Unstable tuning. (20GR105265B tips)
• Excessive green.
• No start-up. intermittently (when cold). (with circuit diagram extract)
• Search jumps on UHF. (PHILIPS - 20GR105265B information)
• Appliance will not switch on at times, but hums in the power supply section.
• No transmitters to adjust and the sound is not controllable.
• No start up. No standby. Attempts to start up, but fails. (PHILIPS - 20GR105265B information)
• Tuning procedure.
• No function. Standby LED flashes briefly. (+ extract of circuit diagram) (20GR105265B tips)
• Does not regulate +95V.
• The following production changes were introduced to prevent the set coming on in the store lock mode when switched on from standby. (picture attached)
• Green screen with flyback lines. Green oscillations. Noise as if HV leaky on picture tube base. (+ extract of circuit diagram)
• Line output transistor becomes warm and in the course of time it becomes defective. (+ extract of circuit diagram)
• Line out of phase. Black band in centre of screen. No colour.
• Volume goes to max. No volume control. (20GR105265B tip from PHILIPS)
• Intermittent colour.
• Secondary main power supply OK except +9V at 5.8V (service info for PHILIPS -20GR105265B)
• Sometimes when turned on, green screen only with flyback lines, at other times no tuning and channel will not change. (part of circuit diagram displayed)
• The tone (sound) tunes well, but the volume cannot be raised.
• No functions. Slow start-up. (part of circuit diagram displayed)
• Two lines going around. (part of circuit diagram displayed)
• Strongly distorted sound by low volume.
• No picture or sound but RCU works correctly. LED flashes when the handset is tried. (part of circuit diagram displayed)
• CRT types. (20GR105265B PHILIPS repair tip)
• Replacing the EAROM. (extract of circuit diagram attached)
• Line output transistor replacement.
• Limited volume. No channel search.
• Volume varies. depending on picture content. (with circuit diagram extract)
• Modification introduced to +9V supply.
• Intermittent channel drift in UHF. Channel search OK. VHF OK.
• Hazy flickering picture at top. (part of circuit diagram displayed)
• Appliance does not function with standby light flashing.
• Dark picture. Audio OK .
• Cannot be programmed and search does not function. Only limited volume adjustable.
• Replacement of surface mounted diode 6637. (picture attached)
• Skips channels during tuning. (picture attached)
• Turns on automatically. No RC or front panel controls.
• No SOP supply. (with circuit diagram extract)
• Excessive brightness.
• Green raster. Faint picture. Flyback lines.
• To release hotel mode (child lock).
• Buzzing sound then switches off.
• Blue picture. Coloured lines.
• White screen with flyback lines. Excessive brightness which increases until PSU switches to protection mode. (extract of circuit diagram attached)
• Whistling from PSU. (+ extract of circuit diagram)
• No sound or picture. Low hum from speaker. (part of circuit diagram displayed)
• Vertical amplitude cannot be fully adjusted, TXT lines can be seen. (extract of circuit diagram attached)
• To put into hotel mode.
• Intermittently narrow picture, but corrects itself shortly after.
• Dead. Power LED is OFF (ON in standby). Hissing from PSU.
• Programme tuning difficulty, stations shifted on tuning bar. (+ extract of circuit diagram)
• No start-up. when cold. (part of circuit diagram displayed)
• Initial volume level is higher than maximum Hotel mode setting.
• How to de-activate Hotel-Mode. (20GR105265B tips)
• No audio.
• No horizontal synchronisation. (extract of circuit diagram attached)
• No audio.
• How to de-activate Hotel-Mode:
• Intermittent colour and intermittent dark vertical bar on picture.
• Noise in audio.
• Line output transistor running hot. (part of circuit diagram displayed)
• Picture fails for a short time. (picture attached)
• Comes on in standby. When program button pressed standby lamp blinks then goes off.
• Unstable tuning.
• No connection for headphone.
• Picture displays lines and strange foldover effect at centre.
• No operation.
• Standby just pulsing.
• Low 5V to micro chip. (+ extract of circuit diagram)
• Programme channel search cannot be called up.
• Colour disappears with VCR-scan (picture search). (part of circuit diagram displayed)
• No line output.
• Memory loss. (part of circuit diagram displayed)
• Line transistor 7528 blows within 1 sec. (+ extract of circuit diagram) (20GR105265B PHILIPS repair tip)
• How to de-activate Hotel mode.
• Difficult startup. Rattling sound from line output trafo.
• Initial volume level is higher than maximum Hotel mode setting.
• Right hand side of screen has a line.
• Sound returns gradually after channel change. (part of circuit diagram displayed) (20GR105265B tip from PHILIPS)
• After switching on the CTV "EXT...1.2.3..." appears on the screen.
• Difficult to tune programmes, stations shifted on tuning bar.
• Sound varies with picture content.
• No line start up; +95 available; +9V is about 4.5V. (part of circuit diagram displayed)
• V-centre adjustment procedure.
• Dead. Low hum.
• "Store" key does not work. (extract of circuit diagram attached)
• No voltage from PSU, computer does not work. (part of circuit diagram displayed)
• Line down middle of screen. (extract of circuit diagram attached)
• No vertical deflection. (+ extract of circuit diagram)
• Horizontal hold adjustment procedure.
• No switch on. Low noise on sound. (picture attached)
• The removal of leaded diodes. (part of circuit diagram displayed)
• Picture shifts. (picture attached)
• Picture is poor with rippling on verticals. (part of circuit diagram displayed)
• Dead with whistling noise coming from power supply. (with circuit diagram extract)
• Green picture. (picture attached)
• Appliance hums slightly (no speaker) horizontal end stage and power supply transistor are ok. Unfortunately no service instructions available.
• Defective purity.
• Picture only in two bars in upper screen section, the rest is dark. (extract of circuit diagram attached)
• Appliance is dead with standby LED flashing after a few seconds. (extract of circuit diagram attached)
• Power supply fault finding. (with circuit diagram extract)
• Won't tune a new channel. Won't activate store function. Picture OK. Sound OK.
• Line output stage does not function.
• Does not shut down (when cold).
• Service manual correction. (part of circuit diagram displayed)
• Sound motorboating when cold. (+ extract of circuit diagram)
• Intermittent colour. (20GR105265B PHILIPS repair tip)
• Quick hiccup. (picture attached)
• No start-up. Standby LED flashes .
• No audio.
• Initial volume level is higher than maximum Hotel mode setting.
• Memory cannot be opened via "rhombus". Stored channels cannot be changed.
• Identification coil adjustment.
• No picture. OSD OK .
• No picture. (+ extract of circuit diagram)
• After operating for one hour it is no longer possible to switch over programmes not even from the front panel. Appliance must be switched on and off then it is possible to change channels.
• Horizontal oscillator adjustment procedure.
• Line output stage only starts up for a short time. (picture attached)
• Production change to line drive. (picture attached)
• Rolling or jittering picture. (extract of circuit diagram attached)
• Vertical roll. (part of circuit diagram displayed)
• No audio.
• Cannot change tuning or stored settings. (+ extract of circuit diagram)
• Excessive horizontal size.
• Menu rolling. (with circuit diagram extract)
• Dim picture with Hanover bars visible. (extract of circuit diagram attached)
• Horizontal white line.
• Difficultly in tuning to correct position.
• SIF DET adjustment procedure.
• Power supply does not oscillate. (extract of circuit diagram attached)
• Enable Hotel mode.
• Dark picture.
• Programs and PP-settings cannot be changed.
• Delay RF AGC adjustment procedure. (20GR105265B tip from PHILIPS)
• Bell filter adjustment procedure.
• No start up, just a buzzing noise in speakers. (picture attached)
• After replacement of the line output transistor BUT12, picture with trapezoid effect, BUT12 overheats and goes defective again. (with circuit diagram extract)
• Dead. At switch on the stand by LED flashes.
• Green picture with retrace lines. After a few restarts picture OK.
• Blown chopper. (with circuit diagram extract)
• Colour sync adjustment procedure.
• No freeze frame or intermittent freeze frame; no sound. (part of circuit diagram displayed)
• Protection device (thyristor THY6641) is triggered at switch on. (with circuit diagram extract)
• 95V available. 9V is only 5.2V. Slight buzzing from loudspeakers.
• No power with abnormal sound. (with circuit diagram extract)
• Line tearing, especially with bright scences. (part of circuit diagram displayed)
• Connection of a loop system to the TV.
• Intermittently dead. (picture attached)
• Change of C2523.
• Tuning drifts. only on certain channels (after a while).
• Dead when switched on via mains switch. Though appliance is on, red LED flashes. Can be switched over to standby. If left in standby for 1 hour and then switched on via RC, functions.
• White unmodulated raster. Picture missing. (extract of circuit diagram attached)
• No colour and vertical black bar across screen.
• Dead. (+ extract of circuit diagram)
• No tuning. (picture attached)
• No standby, humming and standby LED blinks.
• Picture shifted to the right. (picture attached) (20GR105265B PHILIPS repair tip)
• Interference in audio. Interference in picture. (part of circuit diagram displayed)
• No tuning, no remote volume control. (part of circuit diagram displayed) (20GR105265B tip from PHILIPS)
• Enter service mode.
• No function. Standby-LED lights up. Appliance switches on but no picture or sound.
• Switches off by itself. after a while. (part of circuit diagram displayed)
• Sound increases intermittently or "pops", especially during bright scenes. (+ extract of circuit diagram)
• Bright picture. Flyback lines.
• Change of C2523.
• Skips channels during tuning. only on certain channels.
• No HV.
• Enable Hotel mode. Disable hotel mode.
• Change of C2523.
• Right side of picture discoloured.
• Buzz in audio (intermittently). (part of circuit diagram displayed)
• R-Y and B-Y discriminator adjustment procedure. (+ extract of circuit diagram)
• Vertical oscillator adjustment procedure. (20GR105265B tips)
• Poor sync. AGC fault.
• No start-up. Buzzing from speakers and working noise of PSU.
• Excessive HV. after a while.
• Spurious nonsense OSG. Goes to standby after 0.5-2hrs. Loss of tuning.
• Hums softly. (extract of circuit diagram attached)
• Poor reproduction of copy protected tapes. (+ extract of circuit diagram)
• Error codes.
• The fuse and the bridge diodes in the power supply blow.
• Settings do not stay in position. (20GR105265B tip from PHILIPS)
• No picture (when cold).
• Does not switch on. LED is lit in standby. If appliance is switched on with RC, LED switches off.
• Stored channels drift off tune briefly after switch on. Crackle in sound.
• Using a lamp as a load. (PHILIPS - 20GR105265B information)
• SOPS defective. (picture attached)
• No functions. Sound buzzes in loudspeaker. (extract of circuit diagram attached)
• Appliance can not be programmed. Search does not function. Only limited volume control.
• No function. Motorboating from PSU. TV starts up randomly. Intermittent fault.
• Noise in sound. Mute does not function.
• U743 tuner replacement. (+ extract of circuit diagram)
• No picture and sound. Low hum intermittently, no function.
• Picture shifted to the left. intermittently. Line tearing. intermittently. (part of circuit diagram displayed)
• After working normally for a while the TV blocks in any position. The functions do not work.
• Colours flicker and disappears.
• Picture appears slowly.
• Processor numbers (changed).
• Line chirps intermittently. Appliance does not start. Only hum from loudspeakers.
• Intermittently no picture and sound at switch on. Buzz from speaker. (extract of circuit diagram attached)
• Chopper inoperative. (picture attached)
• Switches to standby. (part of circuit diagram displayed) (20GR105265B tip from PHILIPS)
• Dead set. Tries to start. (20GR105265B tip from PHILIPS)
• Reduced horizontal size. (picture attached)
• Vertical line. on the right half screen. (picture attached)
• No start-up. intermittently.
• No colour in OSD.
• No audio.
• Search jumps on UHF.
• Stuck in hotel mode.
• Bright flash on screen and no picture or sound after a few minutes. (picture attached)
• Colour amplitude and phase adjustment procedure.
• Occasionally appliance does not switch on from standby. No further functions are possible.
• Loud chriping after switch on. It becomes lower after a short time.
• Trips. at start-up (intermittently). (with circuit diagram extract)
• Hotel Mode activates by itself. (+ extract of circuit diagram)
• Set won't tune to high frequency channels and lower frequency channels appear to be higher. (with circuit diagram extract)
• Streaks in picture. Picture pulls and rolls intermittently.
• Search jumps on UHF.
• +B very high. (+ extract of circuit diagram) (service info for PHILIPS -20GR105265B)
• Reduced vertical size. at top.
• PAL colour amplitude adjustment procedure.
• Tripping. (extract of circuit diagram attached)
• 10V on 95V line. (+ extract of circuit diagram)
• No picture. Audio OK .
• Correction to service manual LOT winding.
• No switch on after activating mains switch. Whistling noise. (with circuit diagram extract) (service info for PHILIPS -20GR105265B)
• Standby LED lights up and switches off at power on. Appliance will not start up.
• Loosing colour during play-back of a video tape. (part of circuit diagram displayed)
• LED does not flash. Slight buzz in appliance. (+ extract of circuit diagram)
• No channel search. No OSD. (part of circuit diagram displayed)
• Humming, motor noise and other unusual noises. Normal picture.
• LED flashes once, then gurgles. (+ extract of circuit diagram)
• How to switch OFF Hotel-Mode.
• Fizzling sound from speakers at start-up and intermittently picture jagged.
• No or intermittent start-up. (part of circuit diagram displayed)
• Dead. Strange noises from PSU/ line output transformer. (picture attached)
• Slow start-up.
• Buzzing.
• To improve performance with prerecorded cassettes. (with circuit diagram extract)
• Does not stop on stations.
• Unstable tuning.
• Stops working every 2 or 3 hrs. Only starts again after switching off and on again. (20GR105265B tip from PHILIPS)
• Drive for high voltage missing. (picture attached)
• Dead due to action of over voltage protection circuit.
• Will not tune, drifts, colour disappears or interference on a certain channel. (e.g. channel 5 and 59)
• Random breakdown of line output transistor. (extract of circuit diagram attached)
• Slight foldover at upper part of picture if appliance is switched on when cold. Fault disappears after few minutes. (with circuit diagram extract) (20GR105265B PHILIPS repair tip)
• Doesn't tune stations correctly. When cold, crossed lines on low UHF channels. (picture attached)
• +9V supply modification. (picture attached)
• No regulation. (extract of circuit diagram attached)
• Does not start up. Light buzz from loudspeaker. Standby LED produces one brief blink. (PHILIPS - 20GR105265B information)
• Green picture.
• PSU check.
• How to switch off Hotel-Mode.
• White balance adjustment.
• Doesn't store stations correctly.
• No tuning - no channels. (20GR105265B tip from PHILIPS)
• Line output transistor fails repeatedly. (+ extract of circuit diagram)
• Sound varies with picture content. (20GR105265B tips)
• No audio.
• Smeary, washed out picture with bent verticals. (+ extract of circuit diagram) (service info for PHILIPS -20GR105265B)
• No functions. after start-up (intermittently).
• Slow hiccup (extract of circuit diagram attached)
• Dim picture with Hanover bars.
• Local controls inoperative.
• Dead. Low level buzz from loudspeaker. (part of circuit diagram displayed)
• Tuning drifts. only on certain channels.
• No function at switch on from standby. Switches to LOCK (hotel) mode. (+ extract of circuit diagram)
• Replacement of TDA7052 with a TDA7052A.
• Set does not retune or program etc
• Green picture. after warm-up. Lines in picture. after warm-up. Does not change channels.
• Picture centering has shifted horizontally. No OSD.
• How to enter/exit HOTEL mode.
• Colours flickers and disappears.
• Tuning menu can not be called. All other functions OK.
• No picture. No audio. (part of circuit diagram displayed)
• No tuning. No channel lock. (part of circuit diagram displayed)
• No start up from cold and humming.
• How to switch off Hotel-Mode:
• Squealing from PSU.
• No picture, sound ok but on turning up A1 control, frame collapse. (part of circuit diagram displayed)
• Initial volume level is higher than maximum Hotel mode setting.
• Sound goes to max. intermittently and HT varies. (picture attached) (20GR105265B tip from PHILIPS)
• High voltage transistor defective after a while.
• Automatic fine tuning (AFT) field alignment procedure.
• No picture. No sound. Purring sound in loudspeaker. (part of circuit diagram displayed)
• When switching on, only a 10cm stripe on top of screen, the rest of screen is black with flyback lines. After a while, stripe becomes wider. (+ extract of circuit diagram)
• No frame or short frame. (part of circuit diagram displayed)
• No start-up. (with circuit diagram extract)
• Buzz in audio. No picture.
• Dead. Only hum from speakers. (with circuit diagram extract)
• No picture. No sound. Switching on and off from Standby OK.
• Reluctant to start from cold (+ extract of circuit diagram)
• Only some programs with snowy picture can be tuned and on band 1 missing some programs. (part of circuit diagram displayed)
• Intermittently dead. after start-up. (20GR105265B tip from PHILIPS)
• Whistling.
• Red picture. Flyback lines.
• No audio.
• Set dead with just 5V on the 95V line. Standby LED is on but set won't start. (part of circuit diagram displayed) (20GR105265B tips)
• No function, starts up from standby, then goes out.
• The remote control only controls the volume and sound-stop. No function with On-Off and channel change-over, although the display for the operation flickers.
• No +9V, line output stage is OK. (+ extract of circuit diagram)
• Unable to tune or set volume in Prefix mode.
• Modification at line transformer position 5530. (extract of circuit diagram attached)
• Colours flickers and disappears.
• Low frequency noise on sound.
• Picture separating line appears. Whistling.
• Reluctant to start up from cold.
• Blank raster. Flyback lines. (+ extract of circuit diagram) (PHILIPS - 20GR105265B information)
• LED switches on then off immediately.
• Poor synchronisation. when cold. (extract of circuit diagram attached)
• Colour flickers. No colour. after a while. (picture attached)
• Low audio. (+ extract of circuit diagram)
• Programme tuning difficulty. Stations has shifted on tuning bar.
• Intermittent destruction of line o/p transistor. (with circuit diagram extract)
• Height excessive. Defective linearity. Field blanking. (part of circuit diagram displayed)
• Field collapse normally with blank picture. (picture attached)
• Failures in the power supply. (part of circuit diagram displayed)
• Distorted audio.
• No functions, hum in loudspeakers. (extract of circuit diagram attached)
• Change of C2523.
• No tuning possible, F2 appears on bottom of picture and S1 on top.
• Adjustment of +95V. (+ extract of circuit diagram)
• No sound. No picture. Faint motorboating noise.
• Trips. (picture attached)
• Comes on for a short time.
• Blank or green raster. Flyback lines. Faint picture or normal picture. (picture attached)
• Crackling and popping in sound after a short time.
• Excessive vertical size.
• Volume change with great fluctuations in brightness. (+ extract of circuit diagram)
• Defective IC7103 SV-production. (part of circuit diagram displayed)
• No tuning bar when install button pressed and set not in hotel mode. (+ extract of circuit diagram)
• Unregulated power supply. Pulsating picture and surging sound. (picture attached)
• No switch on. Weak whistling noise from PSU. LED is OFF.
• No colour. (picture attached)
• Poor sound, cannot be adjusted louder. When adjusting, sound cuts out. (picture attached)
• Line output stage does not start up. (picture attached)
• Microprocessor screening plate. (+ extract of circuit diagram)
• The TV cannot hold the picture.
• 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. (part of circuit diagram displayed)
• Stored channels are partially lost.
• Line output stage TS7528 is defective. (part of circuit diagram displayed)
• How to reset microprocessor.
• Change of C2523. (service info for PHILIPS -20GR105265B)
• No HT from chopper circuit. (part of circuit diagram displayed)
• Description of SMPS. (+ extract of circuit diagram)
• Picture passes out in the centre. (20GR105265B PHILIPS repair tip)
• Hotel mode.
• Tuning drift, when it is hot the tuning is lost on channel change.
• Line output transistor TR7528 fails at switch on.
• Blank raster. No audio. after a while. (picture attached)
• Only half a picture. (extract of circuit diagram attached)
• Does not start up at once from cold.
• No sound or raster. The 95V HT supply is present at the line output stage but there is no line drive. (with circuit diagram extract)
• During picture changes sometimes a volume increase (plop) is heard. (extract of circuit diagram attached)
• Initial volume level is higher than maximum hotel mode setting. (20GR105265B tip from PHILIPS)
• Buzzing from PSU. when cold. (+ extract of circuit diagram)
• Bright flash on screen. No picture or sound. (picture attached)
• Vertical vibration in cold condition of set.
• No function. When switching on with RC, standby LED lights up. (extract of circuit diagram attached)
• Picture shifted horizontally. (+ extract of circuit diagram)
• Lines across top of picture about 8" in first 100 lines. (with circuit diagram extract)
• Intermittent green picture, channels cannot be programmed. (extract of circuit diagram attached)
• Set goes accidentally into hotel mode.
• Microcomputers and screening plate.
• Slow start up of power supply. (picture attached)
• Unstable tuning.
• Low audio.
• PSU does not start up, if appliance was switched off for a day. Appliance functions after short switch on/off. (extract of circuit diagram attached)
• Intermittent colour.