ctx_1769sl_schematic.pdf part of CTX ctx 1769sl schematic ctx_1769sl_schematic.pdf, CTX Monitor CTX1769 ctx_1769sl

Text preview for : ctx_1769sl_schematic.pdf part of CTX ctx 1769sl schematic CTX Monitor CTX1769 ctx_1769sl_schematic.pdf

Back to : ctx_1769sl_schematic.pdf | Home

Check IC701 (TL431), R717 (12K) and capacitor C721 (1uf 50V). If the capacitor has blown apart
and the resistor burnt, check the line output transformer before replacing any components as in my
monitor the transformer had literally melted at one side and a crack surrounded the transformer's
CTX 1569DSE Dead with tripping PSU
middle. Obviously this transformer had developed a EHT to pin 11 short with catastrophic results.
Replacement transformers are available but due to the cost it is usually more economical to scrap the
monitor.
[HV is present for a short while; 250V at collector if it is de-soldered, also when load
CTX is applied with a lamp]. Check downward control/PSU, add 200R to the Ub-supply to
CPS 1560LR . Line output transistor dies soon after switch-on. the line transformer if necessary.
Check diodes and drive control transistor(s) in the width control. Overheating of the
CTX
CPS 1560LR . Too wide and E/W fault. Line transistor becomes hot. line transistor may be due to the line amplitude being too high.

Check ZD101 (18Vdc) in power supply on left near front on main board edge, Q101
(92SK955-2SK956) on black heatsink in power supply, R114 (39R/2W 5%), IC101
CTX
(UC3842 - NTE7096J) and R113 (100R/0.25W 2%)on power supply's small daughter
board, C113 (0.01uF/50Vdc) on daughter board, fuse (2.5A) on left edge of main
CPS 1560LR Dead. board. Solder power supply's small daughter board connections at main board.
CTX CPS 1560LR Dead. Q101 (K118), D102, R104 (0R25/1W), F101 (Gma 3.15A).
Squealing]. D108 (Bym26c), D410 (5thz52), Q402 (A953), R441 (2R2/0.5W), C407
CTX
CPS 1560LR Dead. (432j-pp630).
CTX CPS 1560LR . Power cycles. Q103 (2SC3457), Q401 (2SC3886A)
CTX CPS 1560LR Shakes. Takes approx 15 mins to power up. Check IC101 (UC3842AN), C112 (100/25).
Check D108 (BYM26C), D410 (5THZ52), Q402 (A953), R441 (2.2-0.5W), C407 (432J-
CTX
CPS 1560LR . Dead. Squealing. Pp630).
CTX CPS 1560LR Dim picture. Vertical size expanded. Squigly text. Replace C123 (10uF/250V) and C427 (1uF/200V).
CTX CPS 1560LR . Uneven colour; virtually green. Check C601, C602 and C603 on CRT board.
CTX CPS 1560LR . Intermittent pincushioning. Replace C431 (10uF/250V).
CTX CPS 1560LR . Pincushion when warm. Replace C427 (1uF/200V).
CTX CPS 1560LR E/W failure. Frequency switch does not work. IC402(LM317) and R449 bad solder joint.
CTX CPS 1560LR . E/W error. Replace C427 (1uF/200V).
Check diodes and drive control transistor(s) in the width control. Overheating of the
CTX
CPS 1560LR . Too wide and E/W fault. Line transistor becomes hot. line transistor may be due to the line amplitude being too high.
. Horizontal width and pincushion cannot be adjusted
CTX
CPS 1560LR correctly. IC203 (C4557C).
CTX CPS 1560LR . Problems with the pincushion, related to the heat Clean pot VR407.
Q408 (Ytf630). Resolder area including width pot VR401 and capacitor on the back of
CTX
CPS 1560LR E/W and too wide. the board connected to it. Also resolder L406.
CTX CPS 1560LR Pincushion effect and excessive width. Check Q408 (YTF630). Resolder area including width pot VR401 and L406.
CTX CPS 1560LR . FCC information. DBLCPS1560
CTX CPS 1560LR . Specification. CRT size: 15" SVGA.
CTX CPS 1560LR . Ripples in display like sine waves. Check and replace C118 (100/350V).
A hole is burnt in the PCB. Solder together with bridges R413 (220R), J112 and L406
CTX 46L00-0360LSE. R413 and J112 belong together. L406 comes from the top left-hand
CPS 1560LR Screen collapse. corner. (D. Luetkefent, Raublingen, Germany)
Ripples on display. Shape of a sinewave. After some time
CTX
CPS 1560LR picturepulls in. C118 (100/350) in power supply.
CTX CPS 1560LR . Picture distortion. Check C602, C603 and C604 (2.2/50).
CTX CPS 1560LR Shakes. Check C118 (100/350) and C115 (330/25).
CTX CPS 1560LR Jitter - takes approx 5-6 secs to power up. IC101 (UC3842AN), C112 (100uF/25V), C1xx? (2.2uF/450V) in rear of PCB.
CTX CPS 1560LR Trembles. C118 (100uF/350V), C115 (330uF/25V
CTX CPS 1560LR Horizontal jitters. [Noticeable in 800x600]. Check C115 (330/35).
CTX CPS 1560LR Dim picture. Vertical size expanded. Squigly text. Replace C123 (10uF/250V) and C427 (1uF/200V).
CTX CPS 1560LR O/W connection. Check IC402 and surrounding circuitry for bad solder joints
Replace C115 (330uF/25V) near chopper transformer is low, this supplies HT
CTX
CPS 1560LR . Slight frame jitter on all pictures. smoothing to IC103.
CTX CPS 1560LR . Vertical size fault. Check C118 (100uF/350Vdc) on main board centre.
CTX CPS 1560LR . E/W failure. Frequency switch does not work. IC402(LM317) and R449 bad solder joint.
CTX CPS 1560LR . Contrast control does not work. Defective solder at contrast pot.
CTX PR711T Dead. Check C137 (47uF/250V).
CTX PR705F . PSU is S/C. Q104 (2SK2648), ZD101 (18V), R126(0R22) are defective.
Resolder flyback transformer, in case deflection is available, then line output
CTX transformer is defective. (FEA749 by power components). Protective resistor R405 (1R)
PR700T No picture. Ticking sound. in supply voltage for high voltage can also be defective.
Cleared up a dim screen by adj "screen" cntrl on flyback. The common cause of too-wide in this chassis is one of two high-voltage film caps going bad, C313
Also cleaned crt pins (did the most good). Then the H size & C314, often shorted. Values are roughly 0.01uF, but the exact values will vary due to fine-tuning
CTX
went wide. Cannot find adjust. Diode or cap went?L304 at the factory, so check value. Also, in some, the OEM caps used were polypropylene, not mylar; if
CVP 5468a and L305 does not help. so, replace with same type, to prevent overheating.
Check/replace C454 = 10 uF/250V. It can be accessed without having to disassemble the chassis,
CTX monitor powers up screen blank. Also high pitched whine through a hole in the bottom, under the main PCB. It is also a good idea to check out other electrolytic
2085 in unit. capacitors as well, especially C121 & C104 = 1000 uF/16V.
[LED is green]. Fault can be intermittent. Replace Q335, Q314 and D320 in the
CTX horizontal deflection stage.
1795GM No picture, no HT.
CTX 1795GM Intermittently no picture (occurs often after a few days), green LED turns orange of bad solder joints on the video board.
No sync because (Power Save).
CTX 1795xe . E/W stage is defective. C224 is defective.
Check AC inlet for damaged connections. Remove AC inlet jack and clean tin pins to
CTX ensure solid connection
VL700 Dead.
Check smoothing capacitor C440 (10nF/1kV) for G2 voltage leaky (reading 11K) also
CTX Q415 (BF488, used BF423 OK), R474 (33K/0.5W), Same parts in CTX1569 are Q721,
VL700 Dead. R761 and C733.
CTX VL700 Dead. Power supply ticks]. Check horizontal output transistor and B+ line for a S/C.
CTX VL700 Dead. Check Q313 and Q306.
CTX VL700 Repeat failure of Q415 S/C and R474 burns up. Replace Q415 (BF488), R474 (33K/0.5W) and capacitor C440 (10nF/1KV).
CTX VL700 No display. Power LED on. Check C125.
CTX VL700 SMPS squeals. Picture has ragged edges. Check R124 (82K/1W) for high resistance
CTX VL700 Squealing. No picture. Check R124 (82K/1W).
CTX VL700 . No display. Power LED on. Check C125
CTX VL700 Service mode. . Hold down +/- keys while simultaneously powering up.
CTX VL700 Takes few minutes until screen lights up. Check CRT.
CTX VL700 Picture has ragged edges. SMPS squeals. Check R124 (82K/1W) for high resistance
CTX VL700 . Excessive brightness with retrace lines. Replace R480 (240K/0.25W) next to small transformer T401, with 0.5W.
CTX VL700 Dim picture. [AC ripple]. Check R124 (82K) for O/C.
CTX VL700 . Excessive brightness. Brightness control has no effect. Check Q336, D306, ZD402 and R480
Q336 (JC337-25) (Ecg123ap) leaks, D306 (a91n4148) leaks, ZD402 (12C/1W) S/C,
CTX R480 (240K/0.5W) O/C. Zener and resistor are likely main cause. D306 causes HV
VL700 . Brightness cannot be controlled. loss. Q336 checks ok but does not work.
CTX 1792UA Paralellogramm failure. Capacitor C303 is defective.
CTX 1792UA Pin balance failure. Capacitor C351 is defective
Screen size: 17"
Dot pitch: 0.26mm
Video bandwidth: 135MHz
Horizontal frequency: 30-92kHz
CTX
Vertical frequency: 50-160Hz
Max resolution: 1600x1200 at 70Hz
Resolution at 100Hz: 1024x760
1792UA Specifications. TCO 95
CTX 1792UA Colour drop out. Picture goes dark. Check solder joints on control board.
CTX 1792UA No picture, smoking. Check C609.
CTX 1792UA No contrast. OSD ok. Check IC601.
CTX 1792UA Whistling depending on resolution. On the deflection coil there is a board with coils. Araldit has been spilt on this.
CTX 1792UA No horizontal synchronisation. Replace and adjust IC301
CTX 1792UA Smoking. C673 ist burnt.
CTX 1792UA No function. Check Q313 and Q306. OR Zener diode ZD101 (18V) has short circuit.
CTX 1792UA Horizontal fails continuously after a short time. Check ZD405.
CTX 1792UA No picture. Wrong horizontal frequency. HT ok]. uP is defective.
Check keyboard function and check if mode date can be saved. In case not good check IC501, IC502
CTX
1792UA LED color is green. and XL501, then end of routine. In case it is good end of routine.
CTX 1792UA At times no function at start-up. Load electrolytic C104 charges up to 440V]. R143 is S/C.
CTX 1792UA Dead. Check fuse and D110 (BYM26C).
CTX 1792UA No picture. IC605 is defective.
CTX 1792UA PSU is defective. R124 voltage too high.
R124 in the PSU is defective (high resistive). IC605 (LM2405T) is defective. Then no sync. IC301
CTX
1792UA Picture is dark, makes noises. (C1883CT) is defective.
CTX 1792UA Picture is too bright. No adjustment possible. Resistor R480 O/C.
1. Check power indicator LED. If not good refer to Power Supply CKT Troubleshooting Routine,
otherwise go to next step.
2. Check LED colour. If it is amber refer to Power Saving CKT Troubleshooting Routine. In case it is
green step next.
3. Does image appear? In case not appear step next, else step to paragraph 6).
4. Check (215V), (75V), (25V), (15V), (7V), (5V), (-12V), (12V), if not good see Power Supply CKT
Troubleshooting Routine and Adjustment, else step next.
5. Check if raster appear. In case it appear step next, else see Deflection CET Troubelshooting
CTX
Routine and Adjustment.
6. Check colour performance. If it is good step next, else refer to Video CKT Troubleshooting Routine,
then step next.
7. Check geomertic performance. In case it is good step next, else refer to Deflection CKT
Troubleshooting Routine.
8. Check external switch function. If not good refer to Micon CKT Troubleshooting Routine, otherwise
no trouble found, end of Main Troubleshooting Routine.
1792UA Main Troubleshooting Routine.

Check DC voltage of BD101 (+/-) pins. If not good check P101, F101, L101, L102 and BD101.
Check gate voltage of Q104. If not good check Q101, D105, ZD101, C101, C105, Q104 and R126.
CTX Check AC output of T101 secondary coil. If not good check Q108, RL102 and T101.
Check DC output of Power Supply, if it is not good check D101, D117, D109, D110, D112, D106, from
1792UA Power Supply Circuit Problem. Q107 to Q111.
Check IC501, Q502, Q503, Q108 and signal cable.
CTX Check keyboard function and check if mode date can be saved. In case not good check IC501, IC502
1792UA LED color is amber. and XL501, then end of routine. In case it is good end of routine.
Check voltage of RK, GK and BK. In case it is good check CRT socket and CRT, else step next.
Check voltage of IC601 pin 18, 20 and 23. If it is good check IC604, IC605, Q620, Q621, Q624, Q625,
Q622 and Q623.
Check pin 15 clamping voltage of IC601. In case it is not good check IC601, P605 (12V) pin 13 of
CTX
IC601.
Check signal input at pin 5, 8, 11 of IC601. In case it is OK check R654, R656, IC601, P605 (12V) pin 7
of IC604, else check C603, C610, C615, R602, R605 and R609.
1792UA Video Circuit Problem.
Voltage at pin 2 of FBT is not ok (disconnected pin 1 of FBT and collector of Q403)]. Check 215V,
Q338, R425, L402, C407 and R403.
CTX [Base voltage of Q403 is not ok]. Check T402, Q402 and C414.
[Q338 gate voltage is not ok]. Check IC303, C398, R496, Q333 and Q332.
1792UA No raster. [Q338 gate voltage is ok]. Check R425, R453, L402, L407 and C410.

Short TP301 to ground then adjust free running of H-Hold VR302.
CTX
[Voltage at pin 20 of IC301 is not ok]. Check pin 38 of IC501 (H- F/V), Q507 and Q508.
1792UA H-Asynchronous [Voltage at pin 20 of IC301 is ok]. Check voltage at pin 21, 22, 23 of IC301 and their peripheral parts.
Check IC304, C331, D309 and Q305.
Check base voltage of Q321, Q320, Q319 and Q344 are "L", "L","L", "L" (1792E/ES) when timing is
31K.
Check pin 16, 17, 18, 19 of IC501.
Check base voltage of Q1319, Q320, Q321 are "H", "H", "H". Model (1769E/SE) when timing is 69K.
CTX Check base voltage of Q319, Q320, Q321 and Q344 are "H", "H", "H", "H", model (1792E/SE) when
timing is 92K.
Check Q318, Q317, Q315, C356, C358, C354, C361.
Note: "L" means the voltage between the gate and source is less then (4V) wich can't turn on the
MOSFET. "H" means the voltage between the gate and source is equal or above (4V) wich can turn
1792UA Picture left square is bigger than the right square. on the MOSFET.
H-phase voltage pin 1 of IC501 is not ok]. Check IC502 and IC501.
CTX
1792UA Out of phase. [H-phase voltage pin 1 of IC501 is ok]. Check R501, R327, R271, R223, C326.
Adjust external H- Size and VR301.
CTX [Pin 1 of IC302 is OK]. Check IC304, Q307, Q308, Q309 and Q306 and their peripheral parts.
1792UA Abnormal width. [Pin 1 of IC302 is not OK]. Check pin 29 of IC501 and their peripheral parts.
[Pin 5, 32 of IC501 is not ok]. Check IC501, IC301 and signal cable.
[Pin 5 of IC503 is not ok]. Check IC503.
CTX
Check Pin 2 of IC201.
1792UA No vertical scan. [Pin 2 of IC201 is not ok]. Check IC201, E205, C215 and Q511.
Adjust external switch of side-pin control.
[Voltage on pin 3 of IC301 is ok]. Check IC301.
CTX
[Voltage on pin 3 of IC301 is not ok]. Check pin 36 of IC501.
1792UA Side pin distorsion. [No volatage on pin 36 of IC501]. Check IC501.
Pin 9 of IC301 is not ok]. Check IC301, IC501.
CTX
1792UA V-Asynchronous. [Pin 9 of IC301 is ok]. Check D205, IC201 and C215.
[Pin 4 of IC201 is not ok]. Check IC501.
CTX
1792UA Vertical position. [Pin 4 of IC201 is ok]. Check IC201, D204 and C225.
Voltage on pin 8 of IC301 is not ok]. Check IC501.
CTX
1792UA Vertical size. [Voltage on pin 8 of IC301 is ok]. Check IC301.
CTX 1792UA Q415 and R474 blown repeatedly. Check C440 (10nF/1KV).