[PLUG] Who repairs monitors around town?

[Keith Lofstrom]

Wally Wharton wrote:
> I have a 17" flat screen CRT monitor, barely a year old, that has lost
> its vertical control.  I've sent it back to the manufacturer to be
> repaired once, but two months after the repair, the vertical is shot
> again.  

While it may indeed be the monitor, you should also try replacing the
video cable and VGA board that drives the monitor.  You would get the
same effect (no vertical synchronization, slowly rolling video) if either
of those were intermittent, or the connectors were making bad contact,
so that pin 14 (vertical sync) was not always connected.  

The most likely thing that would fail in the monitor yielding this
symptom is the HD-15 connector, or the circuit board trace connecting
it to the video sync chip, or the video sync chip in the monitor.  I
would guess bad strain relief on the monitor's connector - the cable
puts a lot of leverage on the connector, and the flexing and pressure
probably breaks connections on the circuit board.  This may be a usage
issue rather than a monitor replacement issue.  Make sure there is no
undue pressure on the monitor connector, or the system will break again.

If cable swapping and video board swapping doesn't fix the problem,
it might be an idea to send one or both along with the monitor next
time you send it in for repair, to quell a "somebody else's problem"
attitude on the part of the repair technician.

It sucks that with all the zillions of transistors that go into a
video board and monitor these days, they cannot put in a few thousand
extra to verify the integrity of the video path.  Sadly though, in a
few years we will likely get that "integrity check" in the form of
some "Digital Rights Management" Linux lockout on the video path.

Keith

-- 
Keith Lofstrom           keithl at ieee.org         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs