I've pinpointed my black screen and horixontal compressed line to a bad vertical ic. Now I need to learn how to locate and repair the unit. Thanks!
See attached photo of a typical chip--usually one row of pins (single in line package) and has the Generic part number right on the front--with the number on yours you can Google a pin out which will show what pins are voltage in, output etc.
Some are ones with two rows of pins staggered and offset.
Locate it also by looking for it to be attached to a metal plate for cooling--also when replacing it the white heat transfer grease on the back of it must be replaced with fresh grease--the white heat sink kind used in computers and electronic equipment of all kinds.
Not a bad idea if you had foldover on top of picture to look at the filter caps right around the chip--one will be a feedback cap--usually a 220uf or higher (uf is microfarad and the cap will have two pins with one a plus and the other a negative marked on them--if that cap is open the set will have nearly a full picture but have folded over lines at top of screen---if that fails it shortly gets the chip.
This is a typical one and yours will likely differ in the number of pins--7-13 pins is normal.
SOURCE: CRT TV vert section
Hi,
Vertical linearity is more of a DCV bias issue rather than feedback or AC coupling. Hence it would be more apt to suspect resistors rather than capacitors. Of course, it is also possible that the large IC that drives the Vertical output maybe at fault (least likely) but often would have trimpots for adjustment. Most current designs do away with trimpots and rely on self correcting (feedback loop) which is simply a resistor in the 100k range. In certain instances, it could be a thermistor or resistor or diode limiter attached to the yoke itself.
Best would be to use a service manual or at the very least a schematic diagram with voltage readings and compare actual on PCB against schematic.
If you could post back the make & model or preferably the chassis number of the TV, might be able to comment back known common vertical issues.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
Good luck and kind regards.
Thank you for using FixYa.
SOURCE: orion TV model TV_798 sl (thin line no picture)
problem is with the vertical output circuit. take it to a repair shop and have them fix it.
SOURCE: CRT TV with only a horizontal line through the center of screen.
Hi,
Yeah. Unfortunately you are right. It is normally the ic that controlls power to the gun. And it is expensive.
Your only chance is to find another model of the same TV that some is ready to trash or throw away at low cost and that TV having some other defect. Advertise in the local newspaper or other channels. It is worth a shot.
Cheers
TeaCii
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Apex Rear Projection GB5108 has gone bad (still showing blue compressed horizontal wave on black screen). I located and resoldered the connections on the underside of the vertical ic unit N301N301 (TDA8351). Before I purchase a new unit, are there any other problems I can troubleshoot, such as a bad capacitor? I am not a handy man, and have no idea what to do next. If I do order a replacement vert. ic unit, what is the best way to pull the old one and install the new?
Still looking for help on the Apex Projection GB 5108 blue line problem. Would like to add that before this, we had convergence problems that would lessen as TV became "warned up". It looks like I have a bad capacitor by vertical IC 100uf 35v. Can you give me some advise on how to locate this and what other related parts would be involved. Pictures, diagrams, and a source to purchase these would also be helpful!
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