68KE3912 / SIERRA [TV 70-74 (66-70) cm picture]

• Picture jitters. intermittently.
• 3 mins after start up, the picture turns blue with horizontal white lines then after everything returns to normal. (picture attached)
• No picture or sound. "E" in display. PB via AV ok.
• No picture via E1/E2 SCART. No horizontal/vertical sync. Jagged horizontal and interference lines. Picture OK via RF input, except few shaky lines on top when changing channels.
• IC7260 changed type. (with circuit diagram extract)
• Screen is completely blue with white flyback lines when warm.
• Picture is visible but there is a white veil over screen. Sound OK. (SIERRA - 68KE3912 information)
• Error codes. (picture attached)
• In standby, LED goes off after 10mins and no longer possible to switch on TV. If standby is not used TV functions perfectly. (with circuit diagram extract)
• Pulses on and off. Slowly stays on longer and longer till it finally comes on fully. (service info for SIERRA -68KE3912)
• No raster, EHT and heaters ok. (with circuit diagram extract)
• Horizontal pulling of picture with considerable change in brightness. (part of circuit diagram displayed)
• No colours in SECAM. (part of circuit diagram displayed) (68KE3912 tips)
• Vertical ondulation of the picture. (picture attached)
• 140V rail fails after 5 minutes. (+ extract of circuit diagram)
• Picture appears faintly in black and white. The bottom of the screen is white. (+ extract of circuit diagram)
• No picture, no sound. Display shows "F1". (picture attached)
• Poor contrast, reduced width with ripples down picture. (with circuit diagram extract)
• U743 tuner replacement.
• Picture has shifted to the right. Colours drop out. Picture becomes blue or red. Picture position changes. (extract of circuit diagram attached) (68KE3912 tip from SIERRA)
• No picture via E1. Distorted and saturated picture.
• PSU blown after implementation of modification.
• R2665 O/C. (+ extract of circuit diagram)
• In standby PSU fails and destroys BUT11. (+ extract of circuit diagram)
• Picture jitters. Picture shifted to the right.
• BUT11 blown when switched to standby. Switching on/off with mains switch is OK. (extract of circuit diagram attached) (68KE3912 SIERRA repair tip)
• Pulsating picture. (part of circuit diagram displayed)
• Erratic start-up.
• Vertical lines are jittering, reacting on mains voltage.
• No horizontal deflection. (+ extract of circuit diagram)
• White screen with flyback lines. Sometimes screen becomes black when switching off and then on with mains switch. Sound available. (extract of circuit diagram attached)
• When in standby switch off TV using RC, appliance continues to hiccup.
• Low brightness. Low contrast. when cold. (extract of circuit diagram attached)
• "88" on display at switch on. LED lights.
• Only 'E' on OSD.
• Memory loss of one or two arbitrary programmes. (part of circuit diagram displayed)
• Dotted lines (dashes) flying around on picture--ragged (with circuit diagram extract)
• Screen split into 4 areas: 1. Black bar; 2. Compressed picture with horizontal white lines; 3. Good picture; 4. Black bar. (+ extract of circuit diagram)
• Snowy screen. No RC or front controls. Standby LED and display switched off. Sound and picture ok when restarting TV. (part of circuit diagram displayed)
• No functions. Display flashes .
• Picture flashes and sound cuts out at same time as picture.
• Whistling. after warm-up.
• No channel and no colour when switching off then on with main switch after channel programming.
• Various types of picture tubes CP90.
• No brightness. intermittently.
• Flashing picture. (extract of circuit diagram attached) (68KE3912 tip from SIERRA)
• Black screen. Sound OK. Vertical line on centre of screen when switching off with mains switch.
• Intermittent foldover if brightness is too high. (+ extract of circuit diagram)
• BU trips on mains 220V, heats up on mains 110V. (+ extract of circuit diagram)
• No synchronisation.
• Problems with Fast TXT. Cannot find page 811 whereas in spite of this the page is broadcast. TXT header remains on subtitles. (extract of circuit diagram attached)
• Page 811 appears spontaneously. (with circuit diagram extract) (68KE3912 SIERRA repair tip)
• PSU defective. BUT11 S/C, mains rectifiers and TEA1039 faulty. (part of circuit diagram displayed)
• No picture. Sound hiccups and pops. After some time functions normal again.
• No reception.
• Dark picture. when cold. (picture attached)
• 5V problem, point 42 processor 4.7V is insufficient. The processor does anything. 8.5V on the collector of 7727 is ok. (extract of circuit diagram attached)
• Crackling on picture. Thin black lines than increase in number when cold.
• Whites very faded, very grey. Functions OK.
• Knock sensitive. Interference in picture. (picture attached)
• Height and width decreased with lower half darker. Display shows "88". Faint raster. (with circuit diagram extract)
• Blue screen with white horizontal lines after a few secs. At start up picture ok. Sound ok.
• After 5 mins impossible to change channel from the RC or front panel. Occasionally display goes off.
• E/W fault. (with circuit diagram extract)
• Display remains blocked on E and automatic search does not stop. (extract of circuit diagram attached)
• Poor picture. (picture attached) (68KE3912 tips)
• Stripes in picture. Knock sensitive. (+ extract of circuit diagram)
• No picture (intermittent/intermittently). Picture disappears and screen is white after appliance switches off for a moment.
• Attempts to start up for a second, display shows ''1'' then letter ''E'' and no start-up.
• All horizontal and vertical lines tear in a wavy manner. (extract of circuit diagram attached)
• SOPS blows repeatedly. (part of circuit diagram displayed)
• Black and white picture with no sound at power up. After adjusting colour and sound on front panel, quick flash and program memory is lost. (picture attached)
• Intermittently switches off and picture moves horizontally.
• Weird noises on channels (like EHT flashovers). (+ extract of circuit diagram)
• Horizontal raster lines over entire picture. (picture attached)
• Blue screen. Flyback lines. Fault occurs intermittently. .
• Sound OK at switch on. When volume increased sound becomes unstable and distorted then cuts off 1 min later.
• Noise in audio. intermittently.
• Irregular flashing when picture appears. Starts up normally at switch on.
• Loses sound from memory when TV switched off by the switch. (part of circuit diagram displayed) (68KE3912 SIERRA repair tip)
• Cogging effect on picture. (part of circuit diagram displayed)
• Slow start-up. (part of circuit diagram displayed)
• Power supply blows up.
• No picture. Lines in picture. intermittently. Audio OK .
• R3599 (47R) keeps failing after approx 1 hour. (+ extract of circuit diagram)
• Unstable varicap voltage. (picture attached)
• Green circle on screen with red border, purplish colour.
• Mains rectifier reservoir capacitor C2656 failed. (+ extract of circuit diagram)
• Noise in picture, horizontal lines. Whistle sound in standby.
• Poor RC sensitivity. (with circuit diagram extract)
• 72V instead of 140V on secondary. (+ extract of circuit diagram)
• Vertical lines move slowly to and fro, especially when cold. (+ extract of circuit diagram)
• Picture stays in black and white. Contrast and brightness controls have no effect.
• BUT blows if appliance remains in standby. (extract of circuit diagram attached)
• No start-up. Standby LED does not light. (part of circuit diagram displayed)
• Intermittent HT shutdown. (with circuit diagram extract)
• No start up. F1 displayed. (with circuit diagram extract)
• No picture or sound at start up. OK after approx 15 mins. (+ extract of circuit diagram) (SIERRA - 68KE3912 information)
• Weak contrast. (+ extract of circuit diagram)
• Poor sound in Canal Plus during coded transmissions. Sound OK when in clear and on other channels. (with circuit diagram extract) (68KE3912 tip from SIERRA)
• Faint noise at switch on. (with circuit diagram extract)
• Sawtooth on vertical lines and 'water drop' effect. Fault improves slightly when appliance is hot. (extract of circuit diagram attached)
• 140V HT supply is low at 60-70V. (picture attached)
• Starts up with a click when cold. Distorted picture during 1 min. Picture flickers. (extract of circuit diagram attached)
• Ragged verticals at switch on; OK after 15 mins. (picture attached)
• Dark picture. Audio OK . (extract of circuit diagram attached)
• Distorted audio.
• Black screen. (picture attached)
• Low contrast in picture, impossible to adjust contrast. No sound intermittently. (part of circuit diagram displayed)
• Intermittent hiccups and switch off when cold.
• No picture. No sound. Display remains on E at start up. (part of circuit diagram displayed)
• No sound at switch on. Picture gradually appears after about 2 to 3 mins. (with circuit diagram extract)
• Raster is bright white and approx 3/4 sized. No RC functions.
• Switches to protection mode (intermittently). (with circuit diagram extract) (SIERRA - 68KE3912 information)
• Sound and picture pulsate, appliance cuts out for a minute then works normally. Breakdown especially when cold. Pulsing every two seconds.
• Green flashes in picture.
• TV chatters at times. Tube noise on screen. (picture attached) (68KE3912 tip from SIERRA)
• Tripping. intermittently. (picture attached)
• Line tearing. when cold. (picture attached) (68KE3912 tip from SIERRA)
• No picture. No HT sound. Display OK. (with circuit diagram extract)
• Horizontal foldover.
• Supply voltages collapse under load.
• No contrast. Poor colour. (+ extract of circuit diagram)
• No video signal content on raster. 88 on display. No sound of EHT voltage generation. Lower part of raster darker than top. (part of circuit diagram displayed)
• Shuts down (after start-up). (extract of circuit diagram attached)
• Difficult to switch on. Does not stay in standby. (part of circuit diagram displayed)
• Black screen. Cracking from EHT. White points on screen. (+ extract of circuit diagram)
• Poor width and poor EHT regulation. (extract of circuit diagram attached) (68KE3912 SIERRA repair tip)
• No picture. at bottom. (with circuit diagram extract)
• Later chassis, no picture when first switched on. (picture attached)
• EHT flashovers. (picture attached) (service info for SIERRA -68KE3912)
• Vertical lines. Switches off by itself. intermittently. (with circuit diagram extract)
• No picture when cold. When warmed up, dotted lines appear and vertical deflection is reduced at the bottom. TV works OK after a few mins.
• Pulling at bottom of picture in PAUSE when a video with Foxtrot chassis is connected. (+ extract of circuit diagram)
• Negative picture with black smear on sides of pictures.
• Dead. F1 on display. (with circuit diagram extract)
• Line tearing. (with circuit diagram extract)
• Picture appears slowly. after a few minutes (when cold). (68KE3912 SIERRA repair tip)
• Repeatedly cuts out for a short time when cold. (picture attached)
• Excessive horizontal size. E/W fault.
• Power supply is destroyed when appliance is left in standby. (picture attached)
• Vertical lines show bleeding effect, especially after switch on. (part of circuit diagram displayed) (68KE3912 tips)
• Unstable picture in TXT. Noisy characters at bottom of screen when using TXT. (extract of circuit diagram attached)
• Image is overcontrolled or not standing still.
• Intermittently, picture disappears and screen becomes black. Sound OK. (part of circuit diagram displayed)
• Starts up correctly and switches off with squeaking then LED switches off.
• Memory loss of some pre-programmed programmes.
• Power supply blown or does not operate; BUT11AF failure. (extract of circuit diagram attached)
• No picture (intermittently). (+ extract of circuit diagram) (68KE3912 tips)
• Intermittently switches off then comes back on after several attempts. (68KE3912 tips)
• Stuck in standby.
• Low HV.
• Initially no picture; low contrast picture after a few minutes. (part of circuit diagram displayed)
• Dark picture. (picture attached)
• At high contrast, at bright picture sections, horizontal, fine lines. (with circuit diagram extract)
• Blows fuse. at start-up.
• Streaked picture at start-up.
• No start-up (intermittently). (picture attached)
• Station selector sometimes goes to a station higher than 50.
• After operating normally for a short time some channels disappear. Frequency slip.
• Picture bends inwards. (extract of circuit diagram attached) (service info for SIERRA -68KE3912)
• Vertical waves, frizzy lines. (extract of circuit diagram attached)
• White screen, no sound. No pretuned channel switchover. (+ extract of circuit diagram)
• No sound in IF, except when pressing volume ± button. (picture attached)
• No audio. via speakers.
• Defective vertical linearity. Shading at bottom of picture. (picture attached)
• Extremely strong howl in sound. "E1" appears on display.
• Right side of picture becomes narrower.
• After operating for a few secs, PSU cuts out. It is necessary to wait for a few mins to be able to switch on again. (with circuit diagram extract)
• Significant shifting of picture and black band on the left side of the screen. (+ extract of circuit diagram) (68KE3912 SIERRA repair tip)
• Chopper transistor (BUT11AF) fails repeatedly. (+ extract of circuit diagram)
• Vertical roll.
• Over mains panel. (+ extract of circuit diagram)
• Picture is poor in the beginning, first 2 minutes as if the picture tube is defective. (+ extract of circuit diagram)
• No vertical deflection. (with circuit diagram extract)
• No picture. No audio. intermittently. Horizontal line. in E-E (intermittently).
• Memory loss only on channel numbers 1, 2, 3. All other functions are correct. (+ extract of circuit diagram)
• After playing a few days the fuse blows, the transistor is then defective. The fault occurs in standby. Appliance switches off after a while. (+ extract of circuit diagram)
• Swirling lines across screen. Does not stop in AUTO SEARCH when channel found. (extract of circuit diagram attached)
• Black lines in picture, E/W fault, rattling sound from high voltage area.
• BUT12 becomes hot and fails when switching to standby. (extract of circuit diagram attached)
• At switch on picture is missing. Contrast builds up slowly over about an hour. (extract of circuit diagram attached)
• Incorrect teletext letter at right hand side of each row.
• White vertical line in middle of screen. (part of circuit diagram displayed)
• Horizontal lines. (+ extract of circuit diagram)
• Occasionally the picture pulls. (picture attached)
• Starts up, picture and sound ok. If put into standby, standby LED switches off after 5 secs, then impossible to switch on again. (with circuit diagram extract)
• BUT 11AF blows after a few secs destroying the protection fuse (1:6A). (+ extract of circuit diagram)
• Starts up after replacing defective PSU but white flashes on screen and system diode flashes. (+ extract of circuit diagram)
• Dead. (picture attached)
• No focus (when cold).
• BU508A defective. (extract of circuit diagram attached)
• Connection of a loop system to TV.
• Starts up. Red LED lights up for a few secs then dead. Cycle may be reproduced some 10 secs after.
• No sound. Dark screen. Jerky noise in speaker when pressing volume.
• Dark screen, normal sound when switched on. Picture appears after 2 to 3 mins.
• Poor sound when volume increased. At switch on numerical display lights up and channel change OK. 30 mins later everything returns to normal. (+ extract of circuit diagram)
• Teletext problem with photo-CD.
• Fuse shatters. BUT11 is S/C. (picture attached)
• No functions. (picture attached)
• Intermittently switches off briefly, especially when tapped. (68KE3912 tips)
• The different BU types.
• Trips violently as picture appears.
• No brightness. No contrast. (with circuit diagram extract)
• Distorted picture. No synchronisation (when cold). (picture attached)
• Fuse (1.6) in the power supply blows instantly.
• No RC functions. Other functions OK . (with circuit diagram extract)
• Information for measuring with a constantly defective BU. (picture attached)
• Three small lines at centre of tube. At switch off discontinuous faint vertical bar, burnt screen. (with circuit diagram extract)
• S shape picture.
• Contrast and brightness cannot be adjusted after a while, picture becomes darker.
• No picture, contrast up volts on TDA3562 stuck at 1.5V approx. (extract of circuit diagram attached)
• White stripe on left. (picture attached)
• Channel display keeps going to E. (+ extract of circuit diagram)
• Tube arcing at switch on and switch off. (with circuit diagram extract)
• Picture flickers at high contrast. (+ extract of circuit diagram)
• Waves in picture.
• Picture missing at start up, then appears, but with distorted lines. (picture attached)
• Tuning voltage slow to rise to its normal value (pin 11 of tuner).
• Poor horizontal scanning, like "teeth " to left and right side of picture. (part of circuit diagram displayed)
• Picture jumps 3 mins after start up. Occasionally it turns pink, white, blue or yellow. (with circuit diagram extract) (68KE3912 tips)
• Plopping sound, no picture and sound trips. After a while fault disappears.
• Oscillations in picture, horizontal stripes and oscillations. (+ extract of circuit diagram)
• Slight predominance of the green. The blacks are greenish. Some flyback lines are green. (SIERRA - 68KE3912 information)
• Horizontal waves in picture. Picture improves after longer operation. (+ extract of circuit diagram)
• Microprocessor screening plate. (with circuit diagram extract)
• No RC functions.
• Front buttons not changing channels or occasionally volume will not change.
• Tearing or waves in picture when connecting the TV. Error present even after warm up. (+ extract of circuit diagram)
• Trips when adjusting contrast. (with circuit diagram extract)
• White screen, no sound. An "E" appears on screen. When connecting TV, no. 1 appears, but instantly switches to E.
• Goes dead after changing all mod parts. (+ extract of circuit diagram)
• Brightness varies. (extract of circuit diagram attached)
• No picture. intermittently. (+ extract of circuit diagram)
• Frizzy line on picture. (extract of circuit diagram attached)
• Spontaneously becomes intermittent, caused by interference in the power supply. The appliance gurgles. (part of circuit diagram displayed)
• Lines in picture. on the left. (+ extract of circuit diagram)
• Waves in picture (in verticals, therefore, horizontal fault). (+ extract of circuit diagram)
• Appliance and LED switch off from standby. When warm, display darkens and channels go out of tune. (extract of circuit diagram attached)
• Switches off at random or white picture for a short time. (picture attached)
• When switching on TV it moves frequency. Also sometimes previously memorised channel is missing.
• Dead. after a few minutes. (picture attached)
• Dark picture for 10 mins after switch on. Sound OK then picture appears. Loss of picture when there is a lot of white. Picture OK after 20 mins. (extract of circuit diagram attached)
• Vertical waving of lines for approx 2 mins. (picture attached)
• Blue screen. Flyback lines. Knock sensitive.
• Shuts down. after a while.
• Black screen. Audio OK . (part of circuit diagram displayed)
• Switches to standby. (+ extract of circuit diagram)
• No tuning. only on certain channels.
• Cycles on/off (when cold).
• Sawtooth picture especially when cold. (with circuit diagram extract)
• Vertical lines not linear. (picture attached)
• Reduced horizontal size. (extract of circuit diagram attached)
• Memory loss. only on one channel.
• Low brightness and line ripple. (+ extract of circuit diagram)
• It takes the picture long time to appear and when it does, there is poor contrast. Sound OK. (extract of circuit diagram attached)
• Interference in picture when aerial is touched or when appliance is touched. (extract of circuit diagram attached)
• Hum on B/G standard.
• Appliance pulsates for 10 mins before starting up.
• Starts up at switch on but just as the picture begins to appear the appliance flashes on and off quite violently but irregularly.
• No audio. (+ extract of circuit diagram)
• No front panel function. (+ extract of circuit diagram)
• Picture appears slowly. (extract of circuit diagram attached)
• Tripping. (part of circuit diagram displayed)
• BUT11A and bridge diodes 6657 to 6660 blow after 15 days when selecting a function from standby. (SIERRA - 68KE3912 information)
• Jagged verticals. (+ extract of circuit diagram) (68KE3912 tip from SIERRA)
• Starts up, switches off and starts up again spontaneously or memory loss or sound howling.
• PSU output voltage very high. (part of circuit diagram displayed)
• Picture rolls. (part of circuit diagram displayed)
• Appliance switches off intermittently with flashes. Sometimes channels switch over to PAL.
• Disable hotel mode.
• E/W problem. Image collapses in one point at the centre of the screen.
• Randomly switches off and video mute.
• Intermittently line transistor shorts. (part of circuit diagram displayed)
• No button operation. (+ extract of circuit diagram)
• How to store user controls.
• No front controls and no RC. "88" on display. (with circuit diagram extract)
• Vertical lines serrated on all 5cm's. Sometimes switches off. (+ extract of circuit diagram)
• Intermittent audio. No start-up. intermittently. (+ extract of circuit diagram)
• Blurry picture. Noise in audio.
• Trips. Functions OK after a few mins. When switched off, 3 colours visible (afterglow). OK when subsequently switched on (appliance is warm).
• Picture goes off occasionally or repeatedly flashes off and on. (picture attached) (68KE3912 tips)
• Wavy picture on vertical lines. (part of circuit diagram displayed)
• The picture is too small (height/width) and East/West does not work correctly. (picture attached)
• New type stands.
• When using the Philips teletext kit, there is no teletext.
• Arcing. after a few seconds.
• Height changes with temperature - picture becomes longer.
• T7665 (BUT11AF) and D6657-6660 and fuse 1652 (T1,6A) are defective.
• Signals to BUT11 in PSU and the four 300V diodes are occasionally defective.
• Functions OK but blinking LED. Strange display. (extract of circuit diagram attached)
• Slow to start up 20-30 mins, squealing from line stage. (with circuit diagram extract)
• Weak points in picture. (with circuit diagram extract)
• Pincushion distortion. (+ extract of circuit diagram)
• Colour flickers. (+ extract of circuit diagram)
• Thin horizontal lines on the light screen. No picture.
• Does not switch to standby. (+ extract of circuit diagram) (68KE3912 tips)
• Flashes cyan after warming up. (extract of circuit diagram attached) (68KE3912 SIERRA repair tip)
• Weak unstable vertical when cold. (+ extract of circuit diagram)
• No raster. on lower half screen. (part of circuit diagram displayed)
• LED goes off after 10 mins in standby. TV will not start up again but does so when cold. (+ extract of circuit diagram)
• Tuning drifts. (extract of circuit diagram attached) (68KE3912 tip from SIERRA)
• Fuse 1652 blown at start up. (with circuit diagram extract)
• No picture when switching on. After about 15 minutes the picture appears slowly, but contrast is poor (and hardly adjustable). Various supplied voltages are present. (extract of circuit diagram attached)
• Switches to protection mode (after a few seconds). (part of circuit diagram displayed)
• Break up of picture (dashes on the picture). (+ extract of circuit diagram)
• Vertical line distortion due to contrast excess. (part of circuit diagram displayed)
• Tearing or ripple on picture when turning TV on. Present also after warming up. (extract of circuit diagram attached)
• How to increase safety range. (with circuit diagram extract) (68KE3912 tips)
• TV picture remains when standby selected. Sound is muted and red standby LED comes on. (extract of circuit diagram attached)
• Dark picture. Brightness, contrast and G2 at max. (part of circuit diagram displayed)
• Frayed picture.
• No video after heating up for 1 to 2 hours. (part of circuit diagram displayed)
• Memory switches from 11 to 01 when switching channels quickly.
• 1mm curl in vertical lines. (+ extract of circuit diagram)
• Intermittent loss of power, picture going off for a split sec and display flickers.
• Picture tearing and loss of vertical sync. Tends to improve when hot.
• PSU collapses especially at start up. (picture attached)
• Switches off preceded by varying HT supply. (picture attached)
• No sound. Faint picture caused by lightning. (+ extract of circuit diagram)
• Poor vertical linearity. (+ extract of circuit diagram) (service info for SIERRA -68KE3912)
• No colour. (picture attached)
• When switching TV to standby and turning it off via mains switch, it takes time to start up again.
• No or intermittent picture. Knock sensitive. (+ extract of circuit diagram)
• At switch on makes flashes, short interruption when cold for 1 min then normal. (with circuit diagram extract)
• Intermittently picture is bright or blinking for a fraction of a second.
• No audio (intermittently). (+ extract of circuit diagram)
• Does not tune any station, scanning available but does not stop on any station cause signal is missing. (+ extract of circuit diagram)
• BUT11AF failed. (with circuit diagram extract)
• Fuse 1653 blown. (+ extract of circuit diagram)
• No sound. Dark picture. F1 on display. (picture attached)
• Intermittently chopper transistor fails. (picture attached)
• Line transformer (BU508AF) blown repeatedly at start up. When it blows a noise is heard like arcing in line transformer. (with circuit diagram extract)
• No functions. "E" message in display.
• Switches to standby. at start-up. (picture attached)
• Value of resistor R3628 and type of transistor 7930.
• Dark picture. after a while.
• PSU oscillates. (part of circuit diagram displayed)
• No picture, "E1", after changing fuse 1653 works a couple of hours. (picture attached)
• No picture. Audio OK . (with circuit diagram extract)
• Picture vibrates vertically.
• Audio cuts off and standby LED lights up when selecting standby from RC. Picture remains normal. (+ extract of circuit diagram) (SIERRA - 68KE3912 information)
• Wavy picture. (+ extract of circuit diagram)
• Loud audio (after start-up). Does not alter when ± volume button is pressed. (extract of circuit diagram attached)
• PSU pulsates, sound is audible, words clipped. No brightness.
• Picture jitters.
• Picture drops out for short while (picture becomes white thereby).
• Horizontal tearing. Vertical line tearing. (part of circuit diagram displayed)
• Attempts to start but trips, pulsating rapidly in short intervals.
• Picture remains dark. Contrast, brightness and colour controls ok. (part of circuit diagram displayed)
• Picture becomes darker, then drops out. (picture attached)
• Vertical black lines in picture when in EXT1 mode. (part of circuit diagram displayed) (68KE3912 tips)
• No channels. intermittently.
• No contrast. intermittently. (extract of circuit diagram attached)
• Lines at top of picture and picture image is bent. (picture attached)
• No picture. OK after a while . (with circuit diagram extract)
• TDA3566/N6 (IC7260). (+ extract of circuit diagram)
• No audio. when cold.
• Appliance remains in black and white on VCRs from Far East. (extract of circuit diagram attached)
• BU508 S/C. (extract of circuit diagram attached) (service info for SIERRA -68KE3912)
• Picture and sound appears only after a long time. Raster OK.
• PSU pulsates.
• PSU hiccups.
• Switches to protection mode. No picture. Audio OK .
• Flickering text and apparent tuning drift. (picture attached)
• Switches off intermittently. Switches to PAL at Power On.
• Microcomputers and screening plate.
• No start-up. LED is red .
• Safety test after repair.
• No display. Standby or RC does not function. Slightly snowy picture and no channels are received. Otherwise there is no function. (68KE3912 SIERRA repair tip)
• Colour spots in flat square picture tubes.
• Picture is too narrow. Vertical wavy lines. (picture attached) (68KE3912 tips)
• No TXT. (+ extract of circuit diagram)
• No picture. (extract of circuit diagram attached)
• Slight ripple barely visible. (extract of circuit diagram attached)
• Intermittently cuts out then starts up again and flashes.
• Starts up with grainy and unsynchronised picture.
• Trips. at start-up. (SIERRA - 68KE3912 information)
• Wavy verticals. (with circuit diagram extract)
• Vertical picture shift towards left side. (+ extract of circuit diagram)
• Reduced height and non linear. Scan at bottom half is missing. (part of circuit diagram displayed)
• No horizontal synchronisation. Picture rolls. (extract of circuit diagram attached) (68KE3912 tip from SIERRA)
• No start up. No display or PSU clicks and display pumps. Hit by lightning. (extract of circuit diagram attached)
• Reduced brightness and line ripple. (with circuit diagram extract)
• Low contrast. (extract of circuit diagram attached)
• Dark picture (intermittently). Audio OK .
• PSU pulsates when cold for 1min then picture and sound return.
• No channel search. (+ extract of circuit diagram) (68KE3912 tip from SIERRA)
• Flashing picture. when cold. (picture attached)
• Vertical outline drift.
• Sawtooth vertical lines. (+ extract of circuit diagram)
• All settings are lost at start up via On/Off switch. (with circuit diagram extract)
• No preset levels. Nonsense in display.
• Switching transistor TR7665 (BUT11AF) in the PSU is S/C. (picture attached)
• Fades out or very dim. intermittently. (extract of circuit diagram attached)
• Does not switch to standby. intermittently.
• Occasionally the channel has been erased from the memory, completely at random and in the space of a few weeks. Channel resetting has no problems at all. (extract of circuit diagram attached) (68KE3912 tip from SIERRA)
• Green, bright flyback line. (+ extract of circuit diagram) (68KE3912 SIERRA repair tip)
• Picture crackling, mostly when cold.
• Head does not stop.
• No start-up or no picture. Faltering sound.
• AV correction does not function. (part of circuit diagram displayed)
• Edging becomes blurry when subtitles in picture.
• Red screen. Flyback lines. No luminance. 37V on collector T7407. (part of circuit diagram displayed)
• Switches to standby (intermittently).
• Appliance hiccups (only with white screen during playback). (picture attached)
• Irregular chirping sounds from the power supply, is not stable in stand-by.
• Identification of teletext decoder through microprocessor.
• No raster for 5 mins. (picture attached)
• Occasionally there are breaks in the luminance. (+ extract of circuit diagram)
• Starts up jerkily after 2 mins. Start up is OK when appliance becomes hot after a few minutes.
• 7619 heats up. (part of circuit diagram displayed)
• Fails occasionally. Display is then dark and after mains switch is switched off then on again, runs perfectly again. (SIERRA - 68KE3912 information)
• Slight flyback line, black line.
• Picture flickers (darkens 3 times per second approx).
• E/W distortion. Picture squashed vertically. Poor synchronization. (with circuit diagram extract)
• Strong chirping noise in line transformer. (part of circuit diagram displayed)
• Black screen with sound. If it is switched off and on again with mains switch, sometimes white screen with flyback lines. (picture attached)
• At switch on screen is blurred and slightly green for a few seconds.
• Repeated failure of the supply. (picture attached)
• BUT11 and diode 1N5061 become S/C. (part of circuit diagram displayed)
• Picture takes time to appear at Power On and sound is very loud. No function keys. Erratic functions. No display.
• Intermittently picture collapse. PSU switches off for a short time. (with circuit diagram extract)
• Switches off by itself. intermittently. (+ extract of circuit diagram)
• Picture can't be centered, left part of picture shifts back. (picture attached)
• No blue. Poor colour. (picture attached)
• Ticking noise. at start-up (intermittently).
• Intermittently trips and/or reverts to channel 1.
• Frizzy lines from top to bottom of picture. (with circuit diagram extract)
• No HV. (picture attached) (SIERRA - 68KE3912 information)
• No sound. No picture. Displays "88". 2 LEDs light up.
• Curling on the line. (SIERRA - 68KE3912 information)
• Picture has flashing line across. (with circuit diagram extract)
• At switch on channel no. displayed then goes into -E-. Impossible to change channels, OK in video. (68KE3912 tip from SIERRA)
• Channel 39 is unstable. (+ extract of circuit diagram)
• 5cm missing in lower part of picture. (picture attached)
• CTV functions when switched on by the switch. If switched off by the RC, impossible to switch on again by RC or by switch. Once cold, it can be started again only by the switch.
• Power supply defective. (68KE3912 SIERRA repair tip)
• BUT11 burnt. (+ extract of circuit diagram) (service info for SIERRA -68KE3912)
• The microprocessor is blocked.
• Values of resistors R3658 and R3659. (+ extract of circuit diagram)
• No colour via tuner. Colour buttons do not work. Functions well in RGB via scart.
• 140V is 50V.
• Searches for channels continuously. (+ extract of circuit diagram)
• Waves permanently on verticals with test picture or on picture. (extract of circuit diagram attached)
• Standby does not function, picture remains, sound mutes and standby LED comes on. (with circuit diagram extract)
• No HV. Audio OK . (with circuit diagram extract)
• Green picture with horizontal lines. OK when warm. Whistle in standby. (part of circuit diagram displayed)
• Short picture breaks (white picture).
• Dead. Slight noise from PSU. (picture attached)
• Snow in picture when chassis is tapped.
• Switches to protection mode. after start-up. (picture attached)
• TS7665 fails. (extract of circuit diagram attached)
• Does not switch to standby. Cycles on/off. (part of circuit diagram displayed)
• Line collapses to 2". Dull raster. (extract of circuit diagram attached)
• Intermittent arcing noise with loss of adjustments or goes into PAL or cuts out without the standby light. (extract of circuit diagram attached)
• Knotted lines and verticals on the picture on the left in ext. position. (part of circuit diagram displayed)
• Picture trembles, gets smaller/bigger.
• In EXT position a black vertical line appears on left side of picture. (picture attached)
• PSU output voltages very low.
• Picture has poor colours. Scart output ok, poor scart input. (part of circuit diagram displayed)
• Poor audio.
• Intermittently functions out of control and no channel memory.
• In standby, green horizontal line in middle of screen pulsating. When channel is altered then line becomes brighter with a pulsation. (with circuit diagram extract)
• Does not switch to E-E via scart.
• Dead or very poor power regulation. (+ extract of circuit diagram)
• No front panel function. No RC functions. after a few minutes.
• 09 on display. Rattling noise from speaker. (picture attached)
• Venetian blind effect. (picture attached)
• Thin lines, like pencil lines over the picture.
• Arcing between pin 7 of line transistor and ground.
• White screen. Audio OK . (+ extract of circuit diagram)
• Pulsates and whistling, display lit but no picture. (+ extract of circuit diagram)
• Back-up battery symptoms after replacing memory. (part of circuit diagram displayed)
• Front panel changes up but not down.
• Vertical collapse (intermittently). (with circuit diagram extract)
• PSU functions but supplies low voltages (eg.90V for 140 etc.). Adjustment 3670 functions. (part of circuit diagram displayed)
• Replacing the TXT board. (68KE3912 tips)
• Black vertical lines in picture. (extract of circuit diagram attached)
• Trips for a few seconds before starting up: chassis of an overmain-primary power supply circuit.
• Special settings do not remain in memory.
• Blue picture (after warm-up).
• Channels drift, especially channel 44. Tuner OK. (picture attached)
• Fuse for mains input voltage blown suddenly at switch on. (extract of circuit diagram attached) (68KE3912 tips)
• +140V adjustment. (part of circuit diagram displayed)
• Blue picture. when changing channels.
• Volume varies. (picture attached)
• No red. No blue. (+ extract of circuit diagram)
• Sawtooth around characters for 15 minutes then picture becomes normal. (extract of circuit diagram attached)
• Erratic chroma with VCR particularly on special effects. (picture attached)
• No channel storing. intermittently. (part of circuit diagram displayed)
• No start-up. Standby LED flashes . (picture attached)
• No raster. Audio OK . (+ extract of circuit diagram)
• No or intermittent start-up. (with circuit diagram extract)
• Dead. No display. No RC functions. (+ extract of circuit diagram)
• Line time base/video/high frequency fault. (with circuit diagram extract)
• No picture. Thin horizontal bars on the whole of the screen. the pot is adjusted slightly the picture appears but green pulses occur every second. (with circuit diagram extract)
• No display. after a few seconds. No front panel function. No RC functions. (picture attached)
• Patterning on all channels. Appears to go past station when tuning slightly.
• Switches off by itself. Very intermittent fault. May work again after several attempts at switching on.
• Smoke from R3628 (6.8R). (extract of circuit diagram attached)
• When switched on TV starts up correctly. When it goes into standby it switches off completely. When switched on again it starts up again for approx 3 secs then switches off completely. No light is lit.
• No E/W correction. (picture attached)
• Horizontal scanning in middle of screen (foldover) with blurred stripes. (part of circuit diagram displayed)
• Intercarrier rattle in the sound. (+ extract of circuit diagram) (service info for SIERRA -68KE3912)
• Line output transistor fails repeatedly. (extract of circuit diagram attached)
• Only the memory of the channel numbers is lost. (+ extract of circuit diagram) (68KE3912 tips)
• Driver transistor 7630 blown after a few secs. (+ extract of circuit diagram)
• Switches off during program switch-over and when picture turns from bright to dark or vice versa. Clattering from line transformer.
• No contrast control. No brightness control. (+ extract of circuit diagram)
• Screen flashes at start up or intermittently. Then either shuts down without standby or loses all channels or switches to PAL. (picture attached) (68KE3912 tips)
• Dead and makes a loud tripping noise.
• Blank picture for up to 1/2 an hour. (with circuit diagram extract)
• No red. When knocking on TV, screen becomes red and no picture. (extract of circuit diagram attached)
• No picture. at start-up. OK after a while .
• No audio. after start-up.
• No vertical deflection. Line in the middle of frame which does not reach edges.
• Picture ringing plus herringbone pattern and no teletext.
• No tuning. (part of circuit diagram displayed)
• Picture trembles vertically when cold with some programs. OK after warming up.
• Picture turns from white to black (when cold). (picture attached)
• Blows line BU.
• No picture. on upper half screen. (extract of circuit diagram attached)
• Vertical collapse. (extract of circuit diagram attached)
• Hiccups when brightness is high.
• Canal Plus in black and white. Colour ok on other channels. Brightness ok. Colour problems after a certain amount of time. (part of circuit diagram displayed)
• Blank raster. No sound. Channel display shows E.
• Reduced vertical size. Vertical foldover. (with circuit diagram extract)
• No channel display or standby LED. (part of circuit diagram displayed)
• No audio. after a while. Hum in audio. in standby. (extract of circuit diagram attached)
• Intermittently no start up with ON/OFF switch. No standby light or channel display. (extract of circuit diagram attached)
• Intermittently dead. (part of circuit diagram displayed)
• No line drive. (with circuit diagram extract)
• The microprocessor is blocked. No programme indicator (+ extract of circuit diagram)
• PSU not oscillating. (+ extract of circuit diagram)
• Replacing control IC7840. (picture attached)
• Intermittent output from power supply low and pulsing. (68KE3912 tip from SIERRA)
• HT varies, then powers down. (+ extract of circuit diagram)
• Blue picture (intermittently).
• Half of the frame is black. Tuning problems.
• Hiss in audio.
• Burn on board line time base C2611. (+ extract of circuit diagram)
• Vertical foldover at bottom. (picture attached)
• White screen. Flyback lines. (extract of circuit diagram attached)
• Low contrast and no reaction to contrast control. Sound mutes. When adjusting sound (RC or front panel) it returns when key is pressed. (extract of circuit diagram attached)
• No vertical synchronisation. (68KE3912 tips)
• Low supply, +65V instead of +140V. (part of circuit diagram displayed)
• Flashes green for a few minutes when switched on. (part of circuit diagram displayed)
• No start-up. (+ extract of circuit diagram)
• Rippling jagged verticals. (with circuit diagram extract)
• Intermittently flash. System LED flashes but TV does not stop completely.
• Corrugated verticals. (+ extract of circuit diagram)
• No picture or faint picture as A1 advanced.
• No picture, high pitch noise before failure. (+ extract of circuit diagram) (68KE3912 tips)
• RC only functions after 10 minutes. Receiver and RC are OK. There is no small module in power supply. (+ extract of circuit diagram) (68KE3912 tip from SIERRA)
• Blue picture. Flyback lines. (with circuit diagram extract)
• Picture disturbed by a wave visible along the human contours. (picture attached)
• PSU "clatters" when cold. (with circuit diagram extract)
• No picture. Display lights up. (with circuit diagram extract)
• Loud audio (intermittently). (picture attached) (service info for SIERRA -68KE3912)
• Output voltage is reduced. (picture attached)