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Old CRT monitor having no display except single vertical line

  • Thread starter SeventhPrince七少爷
  • Start date


Jan 1, 1970

Anyone knows of the problem causing old CRT monitor to except single
vertical line in the middle of the screen?


James Sweet

Jan 1, 1970
SeventhPrince七少爷 said:

Anyone knows of the problem causing old CRT monitor to except single
vertical line in the middle of the screen?


Problem in the horizontal deflection circuit, could be as simple as a
solder joint, could be more complex, you haven't provided any
information that would allow any specific advice though.


Jan 1, 1970
Hello, SeventhPrince???!
You wrote on 23 Mar 2006 23:19:28 -0800:

S> Hi,

S> Anyone knows of the problem causing old CRT monitor to except single
S> vertical line in the middle of the screen?

S> Thanks.

Scan coils around the CRT neck are open circuit, check for dodgy connections
in this area..

With best regards, 3T39. E-mail: [email protected]

Jeff, WB8NHV

Jan 1, 1970
I would check the deflection yoke itself, as the symptoms you mention
can be caused by open horizontal deflection coils (the coils themselves
are actually open, not just bad connections as the last post
suggested). Solid state monitors and TV sets can exhibit this symptom
(one bright vertical line) when the horizontal coils are open because
SS deflection systems will still allow the HV supply to operate even
when the yoke is defective. This is in sharp contrast to tube-powered
HV supplies used in older television receivers; if the horizontal yoke
coils open in a set of this type, the HV supply will cease to operate.

However, depending entirely upon how old your monitor is, I'd consider
getting a new one rather than having the defective one repaired. CRT
monitors are almost dirt-cheap these days (I bought my present HP 17"
MX-70 monitor for something like $70 after a rebate from Best Buy a
couple years ago after its predecessor quit), so I would think at least
twice before having your monitor repaired. Just to have someone look at
your device in a repair station before repairs are even begun may cost
you more than a brand-new monitor. The reason CRT monitors are so
inexpensive nowadays is they are being phased out, in favor of flat
panels--the same reason CRT-based televisions, large-screen sets and
even combis (TV/VCR or TV/VCR/DVD), are so cheap now. I've seen 19"
sets going for less than $150 at HHGregg, Best Buy and Circuit City,
and smaller sets for well under $100, so really, it is not worth it
anymore to have a TV or computer monitor repaired once the
manufacturer's one-year (in most cases) warranty expires. It's a sad
commentary on life in the USA these days, but we live in a throwaway
society in which it is cheaper in almost every case to buy new when
something breaks down (after the warranty expires) than to have the old
device repaired. Case in point: I have a 19" RCA (Thomson) television I
bought new six and a half years ago. It works fine now, has had only
one repair (for a minor tuner problem), but if it should develop any
kind of problem at this point that puts it entirely out of commission,
I will not have it repaired (I had an extended warranty on it which is
close to expiring, if it has not expired already). After almost seven
years it wouldn't be worth the expense. If the CRT goes (for
example), it could cost me $200+ to have it replaced, not including the
cost of the service call and other expenses. This is more than I paid
originally when I bought the TV in 1999. I can get a new set for a
fraction of that amount today, so I'm not even considering having the
RCA set repaired when it eventually goes belly up. Twenty-five years
ago I'd have had the thing repaired once out of warranty, but not
today. The era of replace after the warranty expires is upon us now,
unfortunately, no thanks to once-proud USA television manufacturers
having shut their US plants down and moved offshore. Zenith, RCA, GE,
Magnavox...these are just marketing names (along with their logos) that
mean nothing anymore. You buy a Magnavox TV today, for example, and,
not surprisingly in this day and age, the chassis is manufactured by
Funai or some other offshore company. Zenith was bought out by
LG/Goldstar in the late 1980s, RCA/GE was taken over by Thomson about
the same time...and on and on the list goes.

Like everything else these days, TV sets are throwaway devices made
by no-name offshore companies, no matter the brand name on the cabinet.
Zenith once was my favorite brand of home-entertainment equipment, but
no more. I wouldn't touch a modern (1990s to now) Zenith-branded TV
today with a ten-foot test probe, although I do have a collection of
1950s-1980s Zenith radios built when the company was still an American
firm based in Chicago. Even my Zenith 19" color TV in my bedroom was
made in Mexico (in the mid-1990s) to the exacting specifications of the
former Zenith Radio Corporation; so were my Zenith R-70 AM/FM
transistor portable radio and a Zenith AM/FM/FM-stereo clock radio.
They work amazingly well for their ages (11 and 25 years respectively).
But, I'll say it again, I would not touch, let alone own a
Zenith-branded television made in the last decade and a half (except my
own set, of course), as these sets are made by offshore companies with
no connection whatsoever to the former Zenith Radio Corporation. When
they moved offshore, the quality of their products went right down the
drain. Even RCA/Thomson has gone well downhill with the rest of them. I
have a friend whose parents bought an RCA 25" Guide Plus+ TV in the
early 1990s to replace a 15-year-old Zenith System 3 console. The RCA
set lasted all of two years, then the CRT blew. They bought a new RCA
Guide Plus+ TV which is still working, but the story of how their first
one went bad after only two years leaves a bad taste in my mouth as far
as RCA quality goes. My own RCA has lasted six and a half years and
still has its original CRT (beautiful picture on cable), but I think I
was lucky to have gotten a good set, considering all the trouble folks
are having with RCA/Thomson televisions these days. As I said, these
sets are not worth the cost of even a service call if they go bad after
the manufacturer's warranty expires. But (sigh) (oh, nuts!) time only
goes forward, and the situation will only get worse and worse before it
improves, if it ever does--which I seriously doubt.

(I hereby grant my permission to snip the part of this post having to
do with TV quality if any reader so desires; I realize that part of the
post could be considered as being controversial or even politically
oriented, and, if the truth be known, it had nothing whatsoever to do
with my original answer to the question about the vertical white line
on a computer monitor screen.)

Jeff, WB8NHV (e-mail addy not shown to deter spammers)
Fairport Harbor, Ohio USA


Jan 1, 1970
Thanks for the answers. Can't replace with new monitor as this is an
old integrated Point of Sales machine somewhat like the Apple CRT
monitor I-Mac