Samsung TXJ2754 bottom half of vertical missing
 

This set has some (1/2 inch) retrace lines at the top of the CRT. From
the center down there is no vertical deflection. I've changed some
capacitors in the vertical along with the vertical output IC (LA7845)
and have the same problem. All low value resistors in Vertical look
good, no obvious signs. Ther are several zener diode that look ok in
circuit along with other diodes / transistors. Does anyone have any
information on this set ? I've Googled and found no vertical problems
with this model. Take Care !

Samsung TXJ2754 bottom half of vertical missing
 

carneyke wrote:
This set has some (1/2 inch) retrace lines at the top of the CRT. From
the center down there is no vertical deflection. I've changed some
capacitors in the vertical along with the vertical output IC (LA7845)
and have the same problem. All low value resistors in Vertical look
good, no obvious signs. Ther are several zener diode that look ok in
circuit along with other diodes / transistors. Does anyone have any
information on this set ? I've Googled and found no vertical problems
with this model. Take Care !



Grab a datasheet for the vertical out IC, check and make sure both
positive and negative supply rails are present if used, aside from that
check any remaining capacitors and solder joints.

Samsung TXJ2754 bottom half of vertical missing
 

Jim,
I think it may be an EPROM problem as searching the WEB pointed to
EPROM problems with this set (although the problems weren't vertical).
I called the owner of the set for the remote (needed to adjust Vertical
heighth / linearity). I'll write the numbers down then adjust them.
I'll also take your advice on the datasheet. Thanks.
James Sweet wrote:
carneyke wrote:
This set has some (1/2 inch) retrace lines at the top of the CRT. From
the center down there is no vertical deflection. I've changed some
capacitors in the vertical along with the vertical output IC (LA7845)
and have the same problem. All low value resistors in Vertical look
good, no obvious signs. Ther are several zener diode that look ok in
circuit along with other diodes / transistors. Does anyone have any
information on this set ? I've Googled and found no vertical problems
with this model. Take Care !



Grab a datasheet for the vertical out IC, check and make sure both
positive and negative supply rails are present if used, aside from that
check any remaining capacitors and solder joints.