20GR105568R / PHILIPS [TV]

• Only half a picture. (part of circuit diagram displayed)
• Initial volume level is higher than maximum hotel mode setting.
• The TV does not stop during the tuning phase.
• Appliance does not function with standby light flashing.
• Interference in audio. Interference in picture. (picture attached)
• No power supply start up in loaded condition (eg. with lamp).
• How to switch off Hotel-Mode: (20GR105568R tip from PHILIPS)
• Production change to line drive. (with circuit diagram extract)
• Sound varies with picture content.
• How to reset microprocessor.
• Tuning drifts. (part of circuit diagram displayed)
• Volume varies. depending on picture content. (part of circuit diagram displayed)
• Appliance will not switch on at times, but hums in the power supply section.
• Store lock on the appliance.
• Horizontal white line.
• Unable to tune or set volume in Prefix mode.
• Menu rolling. (+ extract of circuit diagram)
• No picture. OSD OK .
• No functions. Hum in loudspeaker. No LED lit.
• Automatic fine tuning (AFT) field alignment procedure.
• Doesn't tune stations correctly. When cold, crossed lines on low UHF channels. (with circuit diagram extract)
• Streaks in picture. Picture pulls and rolls intermittently.
• LED flashes once, then gurgles. (part of circuit diagram displayed)
• Hazy flickering picture at top. (with circuit diagram extract)
• Service manual correction. (extract of circuit diagram attached) (PHILIPS - 20GR105568R information)
• No tuning. Impossible to change analog control adjustments (brightness, sound, etc.). (+ extract of circuit diagram)
• Settings do not stay in position.
• No power with abnormal sound. (extract of circuit diagram attached)
• No switch on after activating mains switch. Whistling noise. (with circuit diagram extract)
• How to de-activate Hotel-Mode.
• Buzzing from PSU. when cold. (extract of circuit diagram attached)
• Bright picture. Flyback lines.
• Intermittent colour.
• Dead. Low level buzz from loudspeaker. (with circuit diagram extract)
• No channel search. No OSD. (part of circuit diagram displayed)
• After working normally for a while the TV blocks in any position. The functions do not work.
• Change of C2523.
• Change of C2523. (20GR105568R tip from PHILIPS)
• Intermittently dead. (extract of circuit diagram attached) (20GR105568R tip from PHILIPS)
• Quick hiccup. (picture attached)
• Intermittent channel drift in UHF. Channel search OK. VHF OK.
• Change of C2523.
• Green screen with flyback line. No picture. OSD OK.
• Cannot be programmed and search does not function. Only limited volume adjustable.
• Becomes defective immediately after switch on.
• Red picture. Flyback lines.
• Control panel cover.
• Standby LED lights up and switches off at power on. Appliance will not start up.
• No sound. No picture. Faint motorboating noise.
• Line tearing. on lower half screen. (with circuit diagram extract)
• Blank raster. No audio. after a while. (part of circuit diagram displayed)
• New IR receiver.
• No colour.
• How to de-activate Hotel-Mode:
• Reluctant to start up from cold.
• Sound varies with picture content.
• Humming, motor noise and other unusual noises. Normal picture. (20GR105568R tips)
• No audio.
• Poor reproduction of copy protected tapes. (picture attached)
• No start up from cold and humming.
• Occasionally appliance does not switch on from standby. No further functions are possible.
• Programme channel search cannot be called up.
• No picture. No sound. Purring sound in loudspeaker. (+ extract of circuit diagram)
• Picture centering has shifted horizontally. No OSD.
• Dead. Low hum.
• Buzz in audio. No picture.
• No picture, sound ok but on turning up A1 control, frame collapse. (+ extract of circuit diagram)
• Programme tuning difficulty. Stations has shifted on tuning bar.
• Chopper inoperative. (+ extract of circuit diagram)
• No colour and vertical black bar across screen.
• How to switch off Hotel-Mode.
• No function, starts up from standby, then goes out.
• No sound or picture. Low hum from speaker. (part of circuit diagram displayed)
• Trips. (picture attached) (PHILIPS - 20GR105568R information)
• The tone (sound) tunes well, but the volume cannot be raised.
• Very slight vertical foldover with interferences similar to EHT arcing, especially on very white scenes.
• No functions. after start-up (intermittently).
• No tuning. (with circuit diagram extract)
• SIF DET adjustment procedure.
• Excessive horizontal size.
• No line output.
• During picture changes sometimes a volume increase (plop) is heard. (+ extract of circuit diagram)
• No start-up. intermittently.
• Set dead with just 5V on the 95V line. Standby LED is on but set won't start. (part of circuit diagram displayed)
• The fuse and the bridge diodes in the power supply blow.
• Set does not retune or program etc
• No start-up. Buzzing from speakers and working noise of PSU.
• Line output stage only starts up for a short time. (picture attached)
• Sound increases intermittently or "pops", especially during bright scenes. (part of circuit diagram displayed)
• Microprocessor screening plate. (part of circuit diagram displayed)
• Appliance hums slightly (no speaker) horizontal end stage and power supply transistor are ok. Unfortunately no service instructions available.
• Replacement of TDA7052 with a TDA7052A.
• Line output transistor replacement.
• Defective IC7103 SV-production. (part of circuit diagram displayed)
• Bright flash on screen and no picture or sound after a few minutes. (with circuit diagram extract)
• Volume can't be tuned down. No tuning with RC. (extract of circuit diagram attached)
• Reduced horizontal size. (picture attached) (20GR105568R tip from PHILIPS)
• +9V supply modification. (+ extract of circuit diagram)
• No horizontal synchronisation. (with circuit diagram extract)
• Line output stage does not start up. (picture attached)
• Poor synchronisation. when cold. (+ extract of circuit diagram)
• No connection for headphone. (20GR105568R tips)
• 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.
• No regulation. (+ extract of circuit diagram)
• Trips. at start-up (intermittently). (picture attached)
• No audio.
• Stops at start up. (picture attached)
• Blown chopper. (extract of circuit diagram attached)
• Search jumps on UHF.
• Identification coil adjustment.
• Field foldover at switch on from cold. Effect disappears when appliance warms up. (picture attached)
• Sound goes to max. intermittently and HT varies. (part of circuit diagram displayed) (PHILIPS - 20GR105568R information)
• No OSD. Picture OK .
• 95V available. 9V is only 5.2V. Slight buzzing from loudspeakers.
• Skips channels during tuning. (part of circuit diagram displayed)
• Skips channels during tuning. only on certain channels.
• Set won't tune to high frequency channels and lower frequency channels appear to be higher. (extract of circuit diagram attached) (service info for PHILIPS -20GR105568R)
• Dim picture with Hanover bars visible. (extract of circuit diagram attached) (20GR105568R tips)
• Picture is faint with hanover bars. (part of circuit diagram displayed)
• No functions. when cold.
• No function. When switching on with RC, standby LED lights up. (extract of circuit diagram attached)
• Does not regulate +95V.
• Does not shut down (when cold).
• Green picture after few hours, intermittently fault disappears for short while when switching from a station to another. Strange characters in OSD.
• Picture is poor with rippling on verticals. (picture attached)
• No start-up. intermittently (when cold). (extract of circuit diagram attached)
• Green screen with flyback lines. Green oscillations. Noise as if HV leaky on picture tube base. (+ extract of circuit diagram)
• Low frequency noise on sound.
• Microcomputers and screening plate.
• Tuning menu can not be called. All other functions OK.
• Dead. Power LED is OFF (ON in standby). Hissing from PSU.
• Power supply fault finding. (extract of circuit diagram attached)
• Fizzling sound from speakers at start-up and intermittently picture jagged.
• Stored channels are partially lost.
• Intermittently dead. after start-up.
• Only some programs with snowy picture can be tuned and on band 1 missing some programs. (extract of circuit diagram attached)
• Picture only in two bars in upper screen section, the rest is dark. (extract of circuit diagram attached)
• Whistle.
• No tuning.
• Blank raster. OSD OK .
• No vertical deflection. (extract of circuit diagram attached)
• Blank or green raster. Flyback lines. Faint picture or normal picture. (part of circuit diagram displayed)
• Line output transistor becomes warm and in the course of time it becomes defective. (part of circuit diagram displayed)
• Low 5V to micro chip. (part of circuit diagram displayed)
• Replacing the EAROM. (picture attached)
• 6613 type change. (+ extract of circuit diagram)
• Dead. Only hum from speakers. (+ extract of circuit diagram)
• No picture. No audio. (part of circuit diagram displayed)
• Difficult startup. Rattling sound from line output trafo.
• No audio. (20GR105568R tip from PHILIPS)
• No function. Standby-LED lights up. Appliance switches on but no picture or sound.
• Unstable tuning.
• No voltage from PSU. (picture attached)
• Noise in sound. Mute does not function.
• No sound. Picture OK. After a short time TV stops. High frequency noise from PSU. (with circuit diagram extract)
• Set goes accidentally into hotel mode.
• Spurious nonsense OSG. Goes to standby after 0.5-2hrs. Loss of tuning.
• Dim picture with Hanover bars.
• No functions. Sound buzzes in loudspeaker. (extract of circuit diagram attached)
• Excessive HV. after a while.
• Distorted audio.
• Limited volume. No channel search.
• PAL colour amplitude adjustment procedure.
• New infra red receiver.
• Dead. Strange noises from PSU/ line output transformer. (extract of circuit diagram attached)
• Search jumps on UHF.
• Line output stage does not function.
• Initial volume level is higher than maximum Hotel mode setting.
• No colour. (extract of circuit diagram attached)
• The TV cannot hold the picture.
• Switches off by itself. after a while. (picture attached)
• Picture shifted to the right. (with circuit diagram extract)
• No audio.
• Slight foldover at upper part of picture if appliance is switched on when cold. Fault disappears after few minutes. (with circuit diagram extract)
• Excessive brightness.
• Line chirps intermittently. Appliance does not start. Only hum from loudspeakers. (20GR105568R tips)
• CRT types.
• V-centre adjustment procedure.
• No functions. Standby LED flashes. Relay switches to ON.
• 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.
• Modification introduced to +9V supply.
• Turns on automatically. No RC or front panel controls.
• Print with linearity coil pos. 5800.
• Picture passes out in the centre.
• Sound motorboating when cold. (with circuit diagram extract) (20GR105568R tip from PHILIPS)
• Tuning procedure.
• Picture is mostly green with flyback lines after 10 secs from switch on.
• Memory content dropout at positions 4 and 5.
• Dead due to action of over voltage protection circuit.
• Picture separating line appears. Whistling.
• No picture. (+ extract of circuit diagram)
• Standby just pulsing.
• LED switches on then off immediately. (PHILIPS - 20GR105568R information)
• Searches for channels continuously. (with circuit diagram extract)
• No freeze frame or intermittent freeze frame; no sound. (+ extract of circuit diagram)
• Blue picture. Coloured lines.
• Field collapse normally with blank picture. (+ extract of circuit diagram)
• Picture fails for a short time. (with circuit diagram extract) (20GR105568R PHILIPS repair tip)
• No picture and sound. Low hum intermittently, no function.
• Vertical vibration in cold condition of set.
• How to switch OFF Hotel-Mode.
• Unable to retune set or set analogue levels. Store-lock option may be on "Hotel mode".
• Green picture with retrace lines. After a few restarts picture OK.
• Slow start-up.
• To improve performance with prerecorded cassettes. (extract of circuit diagram attached)
• No start-up. (+ extract of circuit diagram)
• Colours flickers and disappears.
• Colours flickers and disappears.
• Intermittently narrow picture, but corrects itself shortly after. (20GR105568R tip from PHILIPS)
• Line out of phase. Black band in centre of screen. No colour.
• Display goes to F1 a few seconds after switching the set on.
• White unmodulated raster. Picture missing. (picture attached)
• Initial volume level is higher than maximum Hotel mode setting.
• Two lines going around. (extract of circuit diagram attached)
• Intermittent colour.
• No audio.
• 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)
• U743 tuner replacement. (extract of circuit diagram attached)
• No tuning bar when install button pressed and set not in hotel mode. (+ extract of circuit diagram)
• The removal of leaded diodes. (part of circuit diagram displayed) (service info for PHILIPS -20GR105568R)
• Line transistor 7528 blows within 1 sec. (extract of circuit diagram attached) (20GR105568R tips)
• Stations won't change. Picture and sound OK. Other functions OK.
• Buzz in audio (intermittently). (+ extract of circuit diagram)
• Slow start up of power supply. (picture attached)
• Tuning drifts. only on certain channels (after a while).
• Secondary main power supply OK except +9V at 5.8V
• Bell filter adjustment procedure.
• Comes on for a short time.
• White balance adjustment.
• Lines on picture after approx one hour. It consists of a band of bright white lines about two inches wide. (+ extract of circuit diagram)
• Picture displays lines and strange foldover effect at centre.
• Defective purity.
• Comes on in standby. When program button pressed standby lamp blinks then goes off.
• "Store" key does not work. (picture attached)
• To put into hotel mode.
• Focus adjustment. (PHILIPS - 20GR105568R information)
• Error codes.
• SOPS defective. (with circuit diagram extract)
• Random breakdown of line output transistor. (part of circuit diagram displayed) (20GR105568R tip from PHILIPS)
• Line output transistor fails repeatedly. (+ extract of circuit diagram)
• No tuning or on screen tuning display.
• Intermittent audio and picture. (part of circuit diagram displayed)
• Appliance can not be programmed. Search does not function. Only limited volume control.
• No HT from chopper circuit. (extract of circuit diagram attached)
• 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 colour.
• Dead set. Tries to start.
• Horizontal oscillator adjustment procedure.
• Right hand side of screen has a line.
• Dark picture. Audio OK . (service info for PHILIPS -20GR105568R)
• Volume goes to max. No volume control.
• Enable Hotel mode. Disable hotel mode.
• Line tearing and rope effect.
• Stuck in hotel mode.
• No function at switch on from standby. Switches to LOCK (hotel) mode. (part of circuit diagram displayed)
• Intermittent colour and intermittent dark vertical bar on picture.
• No picture (when cold).
• Change of C2523.
• Volume change with great fluctuations in brightness. (+ extract of circuit diagram)
• Does not stop on stations.
• PSU switches off with load at U95V. (picture attached)
• Buzzing. (PHILIPS - 20GR105568R information)
• No colour in OSD.
• Colours flicker and disappears.
• PSU check.
• No functions, hum in loudspeakers. (part of circuit diagram displayed)
• Dead. Only standby-LED works. Responds to TURN ON command, but no image and no sound.
• Modification at line transformer position 5530. (+ extract of circuit diagram)
• Does not start up at once from cold.
• Vertical amplitude cannot be fully adjusted, TXT lines can be seen. (picture attached)
• Excessive green.
• Dark picture.
• No tuning - no channels.
• Rolling or jittering picture. (part of circuit diagram displayed)
• Difficultly in tuning to correct position.
• Won't tune a new channel. Won't activate store function. Picture OK. Sound OK.
• Low audio.
• No frame or short frame. (+ extract of circuit diagram)
• Picture shifted horizontally. (part of circuit diagram displayed)
• The switched-mode power supply cannot be loaded.
• Stuck in standby. (part of circuit diagram displayed)
• No picture or sound but RCU works correctly. LED flashes when the handset is tried. (+ extract of circuit diagram) (20GR105568R PHILIPS repair tip)
• Colour disappears with VCR-scan (picture search). (picture attached) (20GR105568R tips)
• Blank raster. Flyback lines. (part of circuit diagram displayed)
• Power supply does not oscillate. (extract of circuit diagram attached)
• Vertical size varies. intermittently.
• How to de-activate Hotel mode.
• No start-up. Standby LED flashes .
• No transmitters to adjust and the sound is not controllable.
• Vertical collapse. (part of circuit diagram displayed)
• Green raster. Faint picture. Flyback lines.
• Green picture.
• Doesn't store stations correctly.
• Slow hiccup (picture attached)
• Squealing from PSU.
• No +9V, line output stage is OK. (picture attached)
• Protection device (thyristor THY6641) is triggered at switch on. (extract of circuit diagram attached) (20GR105568R tip from PHILIPS)
• Colour sync adjustment procedure.
• Green screen and at other times no tuning. (extract of circuit diagram attached)
• Right side of picture discoloured.
• Frame has shifted sideways. Appliance whistles and does not oscillate correctly. (with circuit diagram extract)
• Line output transistor running hot. (picture attached)
• No tuning. No channel lock. (+ extract of circuit diagram)
• Crackling and popping in sound after a short time.
• Strongly distorted sound by low volume. (service info for PHILIPS -20GR105568R)
• Intermittent destruction of line o/p transistor. (picture attached)
• No audio.
• Stops working every 2 or 3 hrs. Only starts again after switching off and on again.
• Unstable tuning.
• 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. (with circuit diagram extract)
• Memory loss. (extract of circuit diagram attached) (20GR105568R PHILIPS repair tip)
• Hotel mode.
• No voltage from PSU, computer does not work. (+ extract of circuit diagram)
• Local controls inoperative.
• Failures in the power supply. (+ extract of circuit diagram)
• No function. Motorboating from PSU. TV starts up randomly. Intermittent fault.
• Adjustment of +95V. (picture attached)
• Tuning drifts. only on certain channels.
• Dead. (picture attached)
• Programme tuning difficulty, stations shifted on tuning bar. (with circuit diagram extract)
• No picture. No sound. Switching on and off from Standby OK.
• Line down middle of screen. (extract of circuit diagram attached)
• Description of SMPS. (with circuit diagram extract)
• Bright flash on screen. No picture or sound. (part of circuit diagram displayed)
• No start up. No standby. Attempts to start up, but fails.
• To remove store/lock. (20GR105568R tips)
• No tuning possible, F2 appears on bottom of picture and S1 on top.
• Stored channels drift off tune briefly after switch on. Crackle in sound.
• Connection of a loop system to the TV.
• 10V on 95V line. (extract of circuit diagram attached) (PHILIPS - 20GR105568R information)
• Poor synchronisation. (with circuit diagram extract)
• No SOP supply. (part of circuit diagram displayed)
• Height excessive. Defective linearity. Field blanking. (with circuit diagram extract)
• Lines across top of picture about 8" in first 100 lines. (part of circuit diagram displayed)
• After switching on the CTV "EXT...1.2.3..." appears on the screen.
• Dead. At switch on the stand by LED flashes.
• Poor sound, cannot be adjusted louder. When adjusting, sound cuts out. (with circuit diagram extract)
• Does not start up. Light buzz from loudspeaker. Standby LED produces one brief blink.
• Sound returns gradually after channel change. (with circuit diagram extract)
• No operation.
• Loosing colour during play-back of a video tape. (with circuit diagram extract)
• Low audio. (part of circuit diagram displayed)
• Set comes on in store lock mode. (part of circuit diagram displayed)
• Poor sync. AGC fault.
• Whistling.
• Green picture.
• Appliance is dead with standby LED flashing after a few seconds. (picture attached)
• No or intermittent start-up. (picture attached)
• LED does not flash. Slight buzz in appliance. (part of circuit diagram displayed)
• Picture shifted to the left. intermittently. Line tearing. intermittently. (+ extract of circuit diagram)
• No start-up. when cold. (with circuit diagram extract)
• Vertical roll. (+ extract of circuit diagram)
• Dead, very slight whistle from PSU. (service info for PHILIPS -20GR105568R)
• No functions. Slow start-up. (picture attached)
• Dead. Low frequency noise on sound.
• Does not start. Slight buzzing in loudspeaker.
• Search jumps on UHF.
• After replacement of the line output transistor BUT12, picture with trapezoid effect, BUT12 overheats and goes defective again. (extract of circuit diagram attached)
• Green picture. (extract of circuit diagram attached)
• Green picture. after warm-up. Lines in picture. after warm-up. Does not change channels.
• Replacement of surface mounted diode 6637. (picture attached)
• Noise in audio.
• Using a lamp as a load.
• Unstable tuning.
• Picture shifts. (+ extract of circuit diagram)
• Picture appears slowly.
• Dead with whistling noise coming from power supply. (with circuit diagram extract)
• No switch on. Low noise on sound. (+ extract of circuit diagram)
• Sound varies with picture content.
• Loud chriping after switch on. It becomes lower after a short time.
• Difficult to tune programmes, stations shifted on tuning bar.
• No function. Standby LED flashes briefly. (part of circuit diagram displayed)
• Line output stage TS7528 is defective. (extract of circuit diagram attached)
• No line start up; +95 available; +9V is about 4.5V. (+ extract of circuit diagram)
• Initial volume level is higher than maximum Hotel mode setting.
• No audio.
• Hums softly. (picture attached)
• Delay RF AGC adjustment procedure.
• No picture. TXT OK . (with circuit diagram extract)
• 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 switch on. Weak whistling noise from PSU. LED is OFF. (service info for PHILIPS -20GR105568R)
• Cannot change tuning or stored settings. (with circuit diagram extract)
• No standby, humming and standby LED blinks.
• Colour flickers. No colour. after a while. (picture attached) (20GR105568R tip from PHILIPS)
• Unstable tuning.
• Reduced vertical size. at top.
• To release hotel mode (child lock).
• Processor numbers (changed).
• Horizontal hold adjustment procedure.
• Change of C2523. (service info for PHILIPS -20GR105568R)
• How to de-activate volume limiter.
• Memory cannot be opened via "rhombus". Stored channels cannot be changed.
• Programs and PP-settings cannot be changed.
• Vertical line. on the right half screen. (+ extract of circuit diagram) (PHILIPS - 20GR105568R information)
• No picture. Audio OK .
• The following production changes were introduced to prevent the set coming on in the store lock mode when switched on from standby. (with circuit diagram extract)
• How to enter/exit HOTEL mode.
• Programming unoperational. Limited sound adjustment possible.
• No tuning. only on certain channels.
• R-Y and B-Y discriminator adjustment procedure. (+ extract of circuit diagram)
• White screen with flyback lines. Excessive brightness which increases until PSU switches to protection mode. (+ extract of circuit diagram)
• No HV.
• No line output stage. (with circuit diagram extract)
• Wavy picture. on the right.
• Does not switch on, standby LED OK.
• Reluctant to start from cold (extract of circuit diagram attached)
• No tuning, no remote volume control. (part of circuit diagram displayed)
• Vertical oscillator adjustment procedure.
• Enter service mode.
• Whistling from PSU. (with circuit diagram extract)
• Correction to service manual LOT winding.
• Buzzing sound then switches off.
• Hotel Mode activates by itself. (+ extract of circuit diagram) (20GR105568R PHILIPS repair tip)
• Smeary, washed out picture with bent verticals. (part of circuit diagram displayed)
• Colour amplitude and phase adjustment procedure. (20GR105568R tip from PHILIPS)
• Error messages indicated by front display flashing. (picture attached)
• Drive for high voltage missing. (with circuit diagram extract)
• Sound varies with picture content.
• +B very high. (picture attached)
• Will not tune, drifts, colour disappears or interference on a certain channel. (e.g. channel 5 and 59)
• Control micro processors. (PHILIPS - 20GR105568R information)
• Intermittent colour. (20GR105568R PHILIPS repair tip)
• No start up, just a buzzing noise in speakers. (extract of circuit diagram attached) (20GR105568R tip from PHILIPS)
• Line output transistor TR7528 fails at switch on.
• PSU does not start up, if appliance was switched off for a day. Appliance functions after short switch on/off. (picture attached)
• Enable Hotel mode.
• No colour.
• Tuning drift, when it is hot the tuning is lost on channel change.
• Excessive vertical size.
• PSU peeps +95 is ca 0,8v
• Intermittently no picture and sound at switch on. Buzz from speaker. (part of circuit diagram displayed)
• High voltage transistor defective after a while.
• Intermittent green picture, channels cannot be programmed. (with circuit diagram extract)
• Line tearing, especially with bright scences. (picture attached)
• Initial volume level is higher than maximum Hotel mode setting.
• Does not switch on. LED is lit in standby. If appliance is switched on with RC, LED switches off.
• Sometimes when turned on, green screen only with flyback lines, at other times no tuning and channel will not change. (+ extract of circuit diagram) (service info for PHILIPS -20GR105568R)
• Tripping. (part of circuit diagram displayed)
• Switches to standby. (part of circuit diagram displayed)
• Unregulated power supply. Pulsating picture and surging sound. (with circuit diagram extract)