ACER 7276E question

This monitorhad the bottom 1/2 of the raster missing when I first got it.
OK, so I changed the Vert IC TDA8351 and checked all the surrounding
components. and powered it up. I have a normal display with no distortion
but the IC heats up fast. To like 75 or so degrees Centigrade. I have
checked the B+ and all other parts in the vertical ckt and all is normal.
I even tried 3 different TDA8351 to see if I had a bad one. Am I looking
at a defective yoke even though the display is flawless? I did ring the
yoke but I couldn't determine if it was good or bad with all the extra
components added. The schematic just shows the yoke as a coil.
65 to 75 degrees can't possibly be the normal operating temp for that IC.
I would think it should be cooler, around 40 or so.

T.S.


--

debaser at ecn.ab.ca
-@+.%

 

[Heinz Schmitz]

On Fri, 17 Oct 2003 01:30:52 GMT, debaser@ecn.ab.ca () wrote:

This monitorhad the bottom 1/2 of the raster missing when I first got it.
OK, so I changed the Vert IC TDA8351 and checked all the surrounding
components. and powered it up. I have a normal display with no distortion
but the IC heats up fast. To like 75 or so degrees Centigrade. I have
checked the B+ and all other parts in the vertical ckt and all is normal.
I even tried 3 different TDA8351 to see if I had a bad one. Am I looking
at a defective yoke even though the display is flawless? I did ring the
yoke but I couldn't determine if it was good or bad with all the extra
components added. The schematic just shows the yoke as a coil.
65 to 75 degrees can't possibly be the normal operating temp for that IC.
I would think it should be cooler, around 40 or so.

T.S.

Did you check the input pulses with a scope? I once had a HOT that was
getting quite warm though the picture was ok. At last I found out that
the pulse at the base was rising too slowly due to a badly soldered
solenoid. Somebody else had just exchanged the previous HOT without
further checking - made it for half a year.
Much luck,
H.