Phillips/Magnavox Chassis 25800
 

Model # 25TR19C221,
Turn set on and High voltage comes up to about 28K and the set shuts down.
Flyback rings ok using the scope cal jack. Have 130VDC to the H-out
transistor, I did find the Vert IC shorted pin 6 (vert supply) to pin 5
(output). Replaced the IC, But still wont stay on. Tried reducing the line
voltage, still will not stay on long enough to check anything. Cant get any
fault codes,
Anyone have any tips on this one?
Thanks
Charlie

Phillips/Magnavox Chassis 25800
 

may be the high voltage transformer faulty

25F8 was: Phillips/Magnavox Chassis 25800
 

In article ,
says...
Model # 25TR19C221,
Turn set on and High voltage comes up to about 28K and the set shuts down.

Measuring HV is not particularly useful except to tell you that the
horizontal and high voltage circuits work.

I did find the Vert IC shorted pin 6 (vert supply) to pin 5 (output).
Replaced the IC, But still wont stay on. Tried reducing the line voltage,

DO NOT reduce line voltage. This is a switch mode power supply which
will try to draw more current to compensate. You will learn nothing
by reducing line voltage, and may cause further damage.

Anyone have any tips on this one?

These sets have circuits that sample vertical and horizontal sweep so
that they can shut down to protect the CRT in case of scan loss. Since
the vertical section was blown up, I would start there. Verify that you
have both supplies to the vertical IC, at least during the second or so
that the flyback runs before shutting down. If so, are you getting a
ramp on the output? If not, figure out why. If so, check signal path
through pulse buffer transistor to processor.

These are not the easiest to work on, due to complexity and SMD parts,
many of which are on the side of the board you can't get to. So be
prepared to be patient. I chased one around for a couple days before
finding an open zerohm SMD that isn't shown on the schematic.

Phillips/Magnavox Chassis 25800
 

This type of fault can get complex, and require a lot of patients. If the
vertical scan is still failed, the set will not be allowed to start. It is
also possible that the flyback is defective, or there is something on the
secondary side that is loading it.

If the CRT is defective, the set may also go in to the protect mode. You can
usually check this by removing the CRT socket assembly, and then seeing if
the HV will come on and stay on. If so, then you know that there is a short
in the CRT.

If you get high voltage, after shutting the set, make sure you discharge the
CRT at both the anode cap, and at the socket end before putting back the
socket assembly.

--

JANA
_____


"Charlie East" wrote in message
...
Model # 25TR19C221,
Turn set on and High voltage comes up to about 28K and the set shuts down.
Flyback rings ok using the scope cal jack. Have 130VDC to the H-out
transistor, I did find the Vert IC shorted pin 6 (vert supply) to pin 5
(output). Replaced the IC, But still wont stay on. Tried reducing the line
voltage, still will not stay on long enough to check anything. Cant get any
fault codes,
Anyone have any tips on this one?
Thanks
Charlie

Phillips/Magnavox Chassis 25800
 

Update---- Went thru the Troubleshooting from the Phillips Force CD for this
set, It led me to a point where it said I had a Filament problem causing
shutdown. The picture tube Are not shorted to any other pins, Set still
shuts down with the CRT socket removed. I guess this is monitored some where
off the flyback, , Will let you know when I find the problem
Charlie
"JANA" wrote in message
...
This type of fault can get complex, and require a lot of patients. If the
vertical scan is still failed, the set will not be allowed to start. It is
also possible that the flyback is defective, or there is something on the
secondary side that is loading it.

If the CRT is defective, the set may also go in to the protect mode. You
can
usually check this by removing the CRT socket assembly, and then seeing if
the HV will come on and stay on. If so, then you know that there is a
short
in the CRT.

If you get high voltage, after shutting the set, make sure you discharge
the
CRT at both the anode cap, and at the socket end before putting back the
socket assembly.

--

JANA
_____


"Charlie East" wrote in message
...
Model # 25TR19C221,
Turn set on and High voltage comes up to about 28K and the set shuts down.
Flyback rings ok using the scope cal jack. Have 130VDC to the H-out
transistor, I did find the Vert IC shorted pin 6 (vert supply) to pin 5
(output). Replaced the IC, But still wont stay on. Tried reducing the line
voltage, still will not stay on long enough to check anything. Cant get
any
fault codes,
Anyone have any tips on this one?
Thanks
Charlie