Changing LOPT in monitor...

M

Mike Deblis

Guest
Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...
 
Mike Deblis wrote:
Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...
Click to expand...
Ignoring shipping charges, just to bench a monitor is $60 and
up...rather close to the cost of a replacement.
I have been an electronic technician for over 40 years, and never
heard of a "LOPT".
Housesomever, the way to render the HV on the CRT safe, is to first
connect a wire to the chassis and/or the bare wire running around the
outside of the tube (it is contacting the black aquadag on the outer
surface). Make sure it cannot become disconnected.
Then poke the other end (bare wire here) under the HV cap at the CRT
(anode).
Tape it down to the pix tube if you like, to ensure it will not fall
out or be pulled out.

Do your work.

Remove that wire fromthe CRT anode first, and then from the
chassis/ground wire mentioned.
 
You do monitor repairs, and have never heard of a <L>ine <O>ut<P>ut
<T>ransformer??

Mmmmm.

Robert Baer wrote:

Mike Deblis wrote:

Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...


Ignoring shipping charges, just to bench a monitor is $60 and
up...rather close to the cost of a replacement.
I have been an electronic technician for over 40 years, and never
heard of a "LOPT".
Housesomever, the way to render the HV on the CRT safe, is to first
connect a wire to the chassis and/or the bare wire running around the
outside of the tube (it is contacting the black aquadag on the outer
surface). Make sure it cannot become disconnected.
Then poke the other end (bare wire here) under the HV cap at the CRT
(anode).
Tape it down to the pix tube if you like, to ensure it will not fall
out or be pulled out.

Do your work.

Remove that wire fromthe CRT anode first, and then from the
chassis/ground wire mentioned.
Click to expand...
 
Line Out Pput (Power) Transformer ?? Another reference to the Flyback,
Integrated High Voltage Transformer, High Voltage Transformer, Et Al Fin.
The terminology, I believe, initially was used in Europe (British Isles ??),
and has been used internationally for quite a period of time.
I've been involved in Consumer Electronic Device Repairs since the early
60's and ran into this nomenclature in the late 70's while reading some
technical reference manuals from Phillips Corporation. The term has become
interchangeable in the service world because many of us "TV Techs" have
migrated to servicing many other devices, inclusive of computer power
supplies, monitors, video control and switching devices, etc.
It is mandated that the Professionals in these service positions keep
abreast of the changes in technology, inclusive of the terms and references
currently in use. Also the changes in electronic schematic drawings and
diagrams that use visual indications and pictorials not base specifically on
the "Old US Standards". Ok Enuf!! Thanks & Cheers Gov
"Mark (UK)" <jumbos.bazzar@btopenworld.com> wrote in message
news:c5tj4r$8bo$1@sparta.btinternet.com...
You do monitor repairs, and have never heard of a <L>ine <O>ut<P>ut
T>ransformer??

Mmmmm.

Robert Baer wrote:

Mike Deblis wrote:

Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is
running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before
starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...


Ignoring shipping charges, just to bench a monitor is $60 and
up...rather close to the cost of a replacement.
I have been an electronic technician for over 40 years, and never
heard of a "LOPT".
Housesomever, the way to render the HV on the CRT safe, is to first
connect a wire to the chassis and/or the bare wire running around the
outside of the tube (it is contacting the black aquadag on the outer
surface). Make sure it cannot become disconnected.
Then poke the other end (bare wire here) under the HV cap at the CRT
(anode).
Tape it down to the pix tube if you like, to ensure it will not fall
out or be pulled out.

Do your work.

Remove that wire fromthe CRT anode first, and then from the
chassis/ground wire mentioned.
Click to expand...
 
For your safety, send the monitor out for service, to do any work in it.
After changing the flyback, there are a number of safety and operation tests
to do. You will not have access to the necessary equipment at home for this.
It takes more than a simple DVM to work on these.

There are issues for testing and adjusting the HV at the anode, testing the
hold down current and HV safety cut-off, testing the performance of the main
power supply, and etc. There is then the set-up of the CRT screen voltage,
and the beam focus set-up.

If the HV is too high, there is risk of X-Ray radiation exposure. Some
people tend to smirk at this one, but if you venture in to the safety issues
concerning CRT monitors, this is a very serious thing.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Mike Deblis" <mdeblis@hotmail.com> wrote in message
news:HNogc.31424$h44.4576331@stones.force9.net...
Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...
 
"Mark (UK)" <jumbos.bazzar@btopenworld.com> wrote in message
news:c5tj4r$8bo$1@sparta.btinternet.com...
You do monitor repairs, and have never heard of a <L>ine <O>ut<P>ut
T>ransformer??
Click to expand...
I had never heard it called that, either. I still don't know what it means.
Do you mean what we call "power transformer" (which takes the incoming AC
from the line)?
 
"Mike Deblis" <mdeblis@hotmail.com> wrote in message
news:HNogc.31424$h44.4576331@stones.force9.net...
Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is
running,
and after much effort, I've found a spare.
Click to expand...
Alright already! Over here, a LOPT = Line Output Transformer = Flyback
Transformer = FBT

Paranoid Mike
 
"Michael A. Covington" <look@www.covingtoninnovations.com.for.address> wrote
in message news:ysOdnVuLNqWFGh_dRVn-sA@speedfactory.net...
"Mark (UK)" <jumbos.bazzar@btopenworld.com> wrote in message
news:c5tj4r$8bo$1@sparta.btinternet.com...
You do monitor repairs, and have never heard of a <L>ine <O>ut<P>ut
T>ransformer??

I had never heard it called that, either. I still don't know what it
means.
Do you mean what we call "power transformer" (which takes the incoming AC
from the line)?
No.
Click to expand...
The 'line output transformer', operates from the horizontal deflection
'line' drive, in flyback mode, with a voltage multiplier, to generate the
main HT voltage for the tube (hence 'line', and 'output'). As has been said,
changing this, involves resetting most of the high voltage adjustments
around the tube, and implies having th correct manual with the
voltages/tests required, and a suitable high voltage probe for the
testmeter/scope.

Best Wishes
 
"Jerry G." <jerryg50@hotmail.com> writes:

For your safety, send the monitor out for service, to do any work in it.
After changing the flyback, there are a number of safety and operation tests
to do. You will not have access to the necessary equipment at home for this.
It takes more than a simple DVM to work on these.

There are issues for testing and adjusting the HV at the anode, testing the
hold down current and HV safety cut-off, testing the performance of the main
power supply, and etc. There is then the set-up of the CRT screen voltage,
and the beam focus set-up.
Click to expand...
And you actually believe that all professional servicers or even most do
these tests? Geez!

If the HV is too high, there is risk of X-Ray radiation exposure. Some
people tend to smirk at this one, but if you venture in to the safety issues
concerning CRT monitors, this is a very serious thing.
Click to expand...
I do agree that in this case where arcing was the original symptom,
at least a test of the HV after repair should be made to assure that it
isn't excessive.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the feedback form on the S.E.R FAQ Web sites.
 
"Mark (UK)" wrote:
You do monitor repairs, and have never heard of a <L>ine <O>ut<P>ut
T>ransformer??

Mmmmm.

Robert Baer wrote:

Mike Deblis wrote:

Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...


Ignoring shipping charges, just to bench a monitor is $60 and
up...rather close to the cost of a replacement.
I have been an electronic technician for over 40 years, and never
heard of a "LOPT".
Housesomever, the way to render the HV on the CRT safe, is to first
connect a wire to the chassis and/or the bare wire running around the
outside of the tube (it is contacting the black aquadag on the outer
surface). Make sure it cannot become disconnected.
Then poke the other end (bare wire here) under the HV cap at the CRT
(anode).
Tape it down to the pix tube if you like, to ensure it will not fall
out or be pulled out.

Do your work.

Remove that wire fromthe CRT anode first, and then from the
chassis/ground wire mentioned.
Click to expand...
I do know what a line output transformer is, and most places *and
functions ) where they may be used: 1) audio work - mostly Public
Address (PA) systems; 2) the term sometimes is loosely used in RF power
and/or distribution amplifiers; 3) again more loosely used for
transformers in Ethernet and similar communications work.
However, of the many hundreds of computer monitors i have seen, *NOT
ONE* had any such thing and none of them could possibly use such a
thing.
Perhaps you are referring to either (1) the power transformer (from
the incoming power line) - if it had one of them at all; OR (2) the
*flyback* transformer.
 
"Jerry G." wrote:
For your safety, send the monitor out for service, to do any work in it.
After changing the flyback, there are a number of safety and operation tests
to do. You will not have access to the necessary equipment at home for this.
It takes more than a simple DVM to work on these.

There are issues for testing and adjusting the HV at the anode, testing the
hold down current and HV safety cut-off, testing the performance of the main
power supply, and etc. There is then the set-up of the CRT screen voltage,
and the beam focus set-up.

If the HV is too high, there is risk of X-Ray radiation exposure. Some
people tend to smirk at this one, but if you venture in to the safety issues
concerning CRT monitors, this is a very serious thing.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================

"Mike Deblis" <mdeblis@hotmail.com> wrote in message
news:HNogc.31424$h44.4576331@stones.force9.net...
Hi,

I know a bit about low voltage stuff, but I want to change the LOPT in an
Eizo/Nanao monitor.

I know the LOPT is faulty, as it arcs and pops when the monitor is running,
and after much effort, I've found a spare.

The monitor (an excellent F77) is probably not worth sending to a
professional to replace the LOPT as the s/h value is probably only USD
100-200...

What do I need to know about safety in order to change the LOPT? It's
certainly worth trying to repair as the picture quality is excellent, but
not worth dying for !

How do I ensure that there is no HV left in the chassis/tube before starting
work - the monitor has not been powered up for some time (month or so) at
the moment.

What special tools (if any) will I need?

I really don't like really HV stuff much (very healthy respect) and would
appreciate the advice...

Thanks from a slightly paranoid Mike...
Click to expand...
And, like i said, it costs $60 or more, just to "bench" them; and a
replacement would not cost a lot more...
 
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