JVC AV 27850 - common cause for deflection problem?
 

Hi:
The vertical deflection went out on my TV a few days ago. It started
acting funny a few days prior to it going out altogether. I'd turn the
set on and the thin horizontal line would appear, then fully deflect,
and oscillate back a forth a few times, sometimes staying a line for a
min or two, then deflect to full screen, etc. Now it just stays on as a
thin horizontal like across the screen, about 1/8" thick.

Are there any things prone to failure in this set that I should look at?
OR, any common problems with this set in general? e.g. bad solder joints
around?
Thanks for any insight!
John

JVC AV 27850 - common cause for deflection problem?
 

"John Hudak" wrote in message
...
Hi:
The vertical deflection went out on my TV a few days ago. It started
acting funny a few days prior to it going out altogether. I'd turn the
set on and the thin horizontal line would appear, then fully deflect, and
oscillate back a forth a few times, sometimes staying a line for a min or
two, then deflect to full screen, etc. Now it just stays on as a thin
horizontal like across the screen, about 1/8" thick.

Are there any things prone to failure in this set that I should look at?
OR, any common problems with this set in general? e.g. bad solder joints
around?
Thanks for any insight!
John

Solder connections - if the ouput IC hasn't blown by now. Sometimes if you
put it off, the things blow up.

Mark Z.

JVC AV 27850 - common cause for deflection problem?
 

Mark D. Zacharias wrote:
"John Hudak" wrote in message
...
Hi:
The vertical deflection went out on my TV a few days ago. It started
acting funny a few days prior to it going out altogether. I'd turn the
set on and the thin horizontal line would appear, then fully deflect, and
oscillate back a forth a few times, sometimes staying a line for a min or
two, then deflect to full screen, etc. Now it just stays on as a thin
horizontal like across the screen, about 1/8" thick.

Are there any things prone to failure in this set that I should look at?
OR, any common problems with this set in general? e.g. bad solder joints
around?
Thanks for any insight!
John

Solder connections - if the ouput IC hasn't blown by now. Sometimes if you
put it off, the things blow up.

Mark Z.


Hi Mark:
Thanks for the reply...when you refer to 'ouput IC' I assume you mean
IC421 (LA7832 -that produces the deflection)??
Very interesting second part of the story...sometimes I can get back to
normal deflection by cycling through the input selections (AV1, AV2, and
TV)...the changing of the input signal sometimes triggers the deflection
to operate normally. After maybe 3-10 mins, something happens and the
deflection goes away. Guess I need to poke around with a hot soldering
iron...Any additional comments based on this follow-up info?
Thanks
-J

JVC AV 27850 - common cause for deflection problem?
 

The fault symptom looks like there are dry joints around the vertical output
stage.
Take the back of the set and lightly tap the circuit board with the handle
of a screwdriver and confirm that it reacts when tapping the board.

Will.

"John Hudak" wrote in message
...
Hi:
The vertical deflection went out on my TV a few days ago. It started
acting funny a few days prior to it going out altogether. I'd turn the
set on and the thin horizontal line would appear, then fully deflect, and
oscillate back a forth a few times, sometimes staying a line for a min or
two, then deflect to full screen, etc. Now it just stays on as a thin
horizontal like across the screen, about 1/8" thick.

Are there any things prone to failure in this set that I should look at?
OR, any common problems with this set in general? e.g. bad solder joints
around?
Thanks for any insight!
John

JVC AV 27850 - common cause for deflection problem?
 

On this set, usually just soldering the pins of the vertical output ic
will fix it. Chuck

JVC AV 27850 - common cause for deflection problem?
 

Chuck wrote:
On this set, usually just soldering the pins of the vertical output ic
will fix it. Chuck

After taking it apart, I resoldered all the connections in the vertical
deflection section and checked the voltage out of the regulator.
Since I didn't want to reassemble it without possibly fixing it, and
since the set had some other flakey operation, I decided to resolder
mostly ALL the connections - mainly the horz deflection, the CPU, the
tuner board as well as the two massive connectors from tuner to MB, and
the convergance board (on the back of the CRT). The old shotgun approach...

One hour and 15 min later + 1/4 lb solder, I reassembled it and it has
been working fine...even the annoying intermittent turn-off/turn on
problem seems to have gone away. I declared success and put it back on
the TV stand...

Thanks for all the advice!
John