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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Changing LOPT in monitor...
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... |
#2
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Changing LOPT in monitor...
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. |
#3
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Changing LOPT in monitor...
You do monitor repairs, and have never heard of a Line OutPut
Transformer?? 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. |
#4
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Changing LOPT in monitor...
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)" wrote in message ... You do monitor repairs, and have never heard of a Line OutPut Transformer?? 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. |
#5
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Changing LOPT in monitor...
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" wrote in message ... 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... |
#6
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Changing LOPT in monitor...
"Mark (UK)" wrote in message ... You do monitor repairs, and have never heard of a Line OutPut Transformer?? 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)? |
#7
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Changing LOPT in monitor...
"Mike Deblis" wrote in message
... 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. Alright already! Over here, a LOPT = Line Output Transformer = Flyback Transformer = FBT Paranoid Mike |
#8
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Changing LOPT in monitor...
"Michael A. Covington" wrote in message ... "Mark (UK)" wrote in message ... You do monitor repairs, and have never heard of a Line OutPut Transformer?? 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. 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 |
#9
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Changing LOPT in monitor...
"Jerry G." 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. 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. 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. |
#10
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Changing LOPT in monitor...
"Mark (UK)" wrote:
You do monitor repairs, and have never heard of a Line OutPut Transformer?? 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. 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. |
#11
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Changing LOPT in monitor...
"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" wrote in message ... 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... And, like i said, it costs $60 or more, just to "bench" them; and a replacement would not cost a lot more... |
#12
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Changing LOPT in monitor...
In article , Robert Baer
writes I have been an electronic technician for over 40 years, and never heard of a "LOPT". Line Output Transformer, pronounced "loptie". It's what monitor techies in the UK call a flyback transformer. Strictly speaking, I think the word 'flyback' is more correct, since these transformers operate on the flyback principle. The term 'Line output' comes from the earlier days of TV sets, when a conventional transformer was used to boost the horiz pulse to about 9kV, which was then amplified by a tripler module to produce the final anode voltage. -- A. Top posters. Q. What's the most annoying thing on Usenet? |
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