I have a vertical problem Screen squished to about 1/4'. I have
replaced ic401 and a few of the caps around the ic. After i replaced
the ic the picture went back to normal for about 30secs then back to
the same problem. Like I said before I replaced a few of the caps in the
vertical section, I am thinking its a cap , But I do not know what one
to look for. Also I went over all solder joints for cold solders and
everything looks good. If somebody can pont me to the right caps or
parts to look at PLEASE HELP!!
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Yes...this TV may be repaired. The line you describe is in the center and is horizontal across the TV. You will need to resolder the vertical IC pins. This vertical IC is mounted on a large heatsink. Under the board you will see there are 5 or 7 pins that will have rings around them. Resolder these. And you should replace two or three capacitors that are next to this IC. A bad cap will overheat an IC and separate the solder grounds. If you can find my expertise page on this website, you will see the repair in more detail. Thanks for asking and show a few hands of support.
You aren't specsificly dercribe yor tv set. For common TV horizontal problem ;i.e : White line accross the horizontal screen, horizontal band,etc..it's can solved by replacing the IC Vertical/Transistor, and olso to replace the cap nearest the IC.
For common TV Vertical Problem :i.e : White line at the center of the screen (top to bottom),Vertical band,etc...It's can cure by Replacing the Horizontal IC/Transistor,and offcurse the cap's.
Try these first. This TV is an oldie 1988?
POWER SUPPLY STARTS BUT WONT RUN. CHECK FOR SHORTED D909 OFF T905 PIN 17 AND/OR SHORTED IC401. (PCB-MAIN) D909 PT.# 264P521020 IC401 PT.# 272P174010 *** ( TO PREVENT REPEAT FAILURE , REMOVE T905 FROM PCB AND RE-SOLDER LEGS OF TRANSFORMER AND THEN REINSTALL) 2. POWER SUPPLY WONT RUN. CHECK FOR OPEN FOIL AT PIN 2 OF T905. (PCB-MAIN) 3. POWER SUPPLY WONT RUN. CHECK FOR OPEN R903 (220KOHM) AT PIN 3 OF IC901. (PCB-MAIN). ALSO CHECK THE VERTICAL OUT IC, LOOK IN POWER SUPPLY CIRCUIT FOR LEAKY CAPS. YOU CAN TELL BY BLACKNESS ON THE BOARDS ON THE NEGATIVE SIDE OF THE CAPS.
1. SHUTDOWN CAN BE CAUSED BY NO VERTICAL DEFLECTION. SINCE THE VERTICAL CIRCUIT IS POWERED BY THE SWITCHED POWER SUPPLY THE UNIT MUST BE TURNED ON TO TROUBLESHOOT THE CIRCUIT. THIS CAN BE ACCOMPLISHED BY TEMPORARILY DISCONNECTING THE VERTICAL INPUT TO THE X-PROTECT CIRCUIT. ** TO PREVENT DAMAGE TO THE CRT'S YOU MUST UNPLUG THE CRT PCB'S. ** TO DEFEAT THE X-PROTECT CIRCUIT, UNSOLDER D4A1 LOCATED OFF THE COLLECTOR OF Q4A1. IF THE UNIT POWERS ON AT THIS POINT, YOU HAVE CONFIRMED A VERTICAL FAILURE AS THE CAUSE FOR SHUTDOWN. ** D4A1 MUST BE REINSTALLED IN CIRCUIT TO PREVENT CRT DAMAGE. ** 2.CHECK PIN 1 OF IC401 FOR 10.7VDC. IF LOW OR MISSING CHECK FOR SHORTED D4000 LOCATED OFF PIN 1. (PCB-MAIN) D4000 PART #264P487030 3. CHECK PIN 8 OF IC401 FOR 27.7VDC. IF MISSING CHECK FOR OPEN D955 AND L961 AT S1 TERMINAL OF T902. (PCB-POWER) D955 PART #264P102040 L961 PART #411P012010 4. CHECK FOR DEFECTIVE IC401. IC401 PART #272P239040, OR INSTALL PT# IC-401, THIS KIT CONTAINS CAPACITOR C920, D4000 AND IC401. BE SURE TO MOUNT C920 ON FOIL SIDE OF PCB. 5. EXCESSIVE 130V SUPPLY. CHECK C911 47 UFD 100 V AND C914 47 UFD 50 V, IN THE IC900 CIRCUIT.
Good Luck, big IRISH.
vertical deflection problem. Vertical output IC, pump up cap, power to output problem, bad connections, jungle IC. Its a good idea to replace all electrolytic caps near the output IC. Bad caps cause it to run hot and self destruct.
A line running across the screen like that and then returning to a picture I would guess is the vertical IC has some poor solder joints. The vertical IC in that unit IC401 is an LA78041 a seven pin IC that is mounted to a metal heat sink. On the foil or under side of the board take a careful look at the pins of that IC and any that look suspicious carefully re-flow some solder over.. Careful not to keep your iron on the pin too long.. And if have to re-solder several take some time between them to allow the IC to cool so you don't damage it..