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Displays Hardware

DIY LCD Backlight Repair 222

Bill Nye (not the science guy) writes to tell us that InventGeek has an interesting article on do it yourself LCD backlight repair. From the overview: "Those of us that have used LCD monitors for a while know that over time the backlight starts to dim and will eventually completely fail. Leaving you with some electronic scrap that you could sell on eBay for 35 bucks or so. Well for less than $20.00 and about a half hour of your time you can replace the backlight and rejuvenate that monitor to as good as new condition."
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DIY LCD Backlight Repair

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  • Cool! (Score:3, Funny)

    by imadoofus ( 233751 ) on Sunday December 11, 2005 @04:38PM (#14234643)
    Time to buy some cheap monitors on ebay!
  • Laptop Screens (Score:3, Interesting)

    by kermitthefrog917 ( 903403 ) on Sunday December 11, 2005 @04:39PM (#14234644)
    Forgive me for asking...but would a similar process work on laptop screens? I've got an old laptop whose screen is completely fubar and this may be the problem...
    • Re:Laptop Screens (Score:5, Informative)

      by Kredal ( 566494 ) on Sunday December 11, 2005 @04:42PM (#14234663) Homepage Journal
      I have an old HP craptop, about three years old now. I was able to get a new inverter for the screen backlight for about 40 bucks from them... took off the front panel, put in the inverter (simple plugs), and it all worked fine. Ask your laptop maker if they can sell you the part without the service. It is an easy DIY fix.
    • ah yes.. i did one of these for a friend of mine.. actually.. i offered to do one of these for a friend of mine with absolutely NO prior experience or instruction manuals...

      heres how it went..

      day 1. order replacement CCFL from ebay. luckily one seller had it in the original housing meant for my laptop screen. for 50$ + next day shipping - 65$.
      day 3. put in new CCFL after an HOUR of painfully slow and arduous task. removing all the foil tape in once piece. saving and identifying the millions of screws. reapp
    • Yes (Score:5, Informative)

      by stoolpigeon ( 454276 ) * <bittercode@gmail> on Sunday December 11, 2005 @05:00PM (#14234735) Homepage Journal
      and it is easy to do. I'd start with the inverter first and then if that doesn't do it, look at replacing the light. There was an ask slashdot about obtaining lcd parts a while back. You can read good info. in that thread. [slashdot.org]
       
      I also wrote up a journal entry when I fixed my dad's laptop, but I can't find it. (Note to self, do better job with titles)
       
      I was nervous the first time I replaced a laptop inverter - but it was cake. The best place I found to buy the hp inverter I needed was ebay.
    • Re:Laptop Screens (Score:3, Informative)

      by Rxke ( 644923 )
      Did this with a first generation iBook (Clamshell)
      If you google around you generally find alternative replacement lights for little money, compared to the 'official' stuff. Always worth to check for that.
      Be sure to invest some time to try and find a servicemanual, that could save you a lot of headscratching. Laptops are a tad more complicated to dismantle AND put back together than bix boxes, everything is crammed in tiny spaces, lots and lots of screws, sometimes you have to go in in a particular step-by-s
    • Probably not. Laptop screens are a lot more compact, and therefor use much more specialized components. Since the space is tight, you probably can't fit a random cathode ray tube in there. Also, I'm not sure, but don't some laptop screens use LEDs instead of cold cathode tubes?
  • Fry's electronics (Score:5, Informative)

    by t0qer ( 230538 ) on Sunday December 11, 2005 @04:41PM (#14234658) Homepage Journal
    Just FYI Fry's carries everything you need, from those special power modulators to mini flourescent tubes to repair your LCD's.
  • by BalorTFL ( 766196 ) on Sunday December 11, 2005 @04:43PM (#14234667)
    Now we deal with the case lighting. The cold cathode is incased in a plastic case to protect it and defuse the light. We will need to remove the casing very carefully. Most cold cathode tubes have mercury vapor in them this is very dangerous if it was broken. Avoided damaging the bulb at all costs as mercury vapor has been linked to brain damage and cancer. so be careful.... unless your some arch-villain with a diabolical plan.

    Wait... complicated instructions that can lead to brain damage and cancer if done improperly, given to me by a guy who can't be bothered to fix your->you're mistakes? Somehow I don't think I'll be trying this fix any time soon.
  • by Rogerborg ( 306625 ) on Sunday December 11, 2005 @04:45PM (#14234677) Homepage

    A barely legible article that contains the absolute minimum information about a potentially lethal operation involving jillions of volts of capacitance and using power tools to cut almost-but-not-quite into one of the most toxic substances around, which, not at all incidentally, we are advised to just "dispose" of when we're done with it. Gee, I wonder what the author did with his? Tossed it in the garbage, or throw it into the sewer?

    Frankly I'd rather that we just linked to bomb making instructions, as it would probably result in fewer acute injuries and chronic health problems.

    • by TinheadNed ( 142620 ) on Sunday December 11, 2005 @04:55PM (#14234715) Homepage
      Actually there aren't any large capacitors in the backlight of TFTs. I've worked with some invertors and they don't peak at more than 1000V and normally operate at 600V.

      The key trick with this jazz is to find the part number and buy a new one. Much quicker.
    • On the page it rates the "difficulty" of this operation as "novice."
    • by MattskEE ( 925706 ) on Sunday December 11, 2005 @05:08PM (#14234770)
      Anyone who uses the phrase "jillions of volts of capacitance" obviously doesn't understand what's inside an LCD monitor, nor how dangerous it is.

      There is really nothing dangerous in them, LCD's cathodes don't use more than 1kv, and unlike CRT's, there is no significant capacitor that will remain charged when the monitor is turned off. Obviously there would be some risk if you actually worked on the inverter while it was on, which isn't even dangerous if you are careful.

      And if you're that worried about the safety of cutting into a cold cathode, you could always use a shop vac to improvise a fume extraction system, in case you screw it up. Or you could order a harder to find cold cathode that does not have the covering mentioned, or salvage one from a scanner.

      If you take a few minor precautions this operation is not really dangerous at all. Don't complain about how stupid this author is when you don't understand how LCD backlights work or basic safety proceedings.
      • I think his concern is most likely with units that have a built-in PSU. I'd want to be careful with these too. PSUs and CRT monitors are the two things I won't work on for safety reasons.
      • Lets not mislead the reader to believe that a CCFL Inverter won't bite. I use them regularly and whilst they do output a low current, the body certainly can feel the hit from a CCFL driver, infact it puts little burn marks on your skin upon contact. I sure wouldn't recommend playing with this stuff if you had a pacemaker or a weak heart (or had little experience with electronics). It really does make you jump if you touch one of the live outputs.
      • by fireboy1919 ( 257783 ) <rustyp@freeshe l l .org> on Sunday December 11, 2005 @11:22PM (#14236274) Homepage Journal
        Anyone who uses the phrase "jillions of volts of capacitance" obviously doesn't understand what's inside an LCD monitor, nor how dangerous it is.

        Sounds like somebody wishes he was the one who made that comment first. Too late. The comment is out. He's already talked about all the jillions of volts of capacitance that live inside your monitor. You're going to have to talk about something else. Personally, I would have gone for the ultra-dangerous kabillion watt lightening vortex thats in the back of 'em.

        There is really nothing dangerous in them, LCD's cathodes don't use more than 1kv, and unlike CRT's, there is no significant capacitor that will remain charged when the monitor is turned off.

        Well, yeah, obviously. There's clearly no danger from the cathodes. Their capacitors are all tame. Its the doghodes you have to worry about. Their capacitors are easily excitable, and you have to wake them up just right or they end up escaping from your monitor. Those things'll live in your walls for years while slowly eroding the foundation of your house. The only way to get 'em then is highly toxic, massive bug bombs.

        Obviously there would be some risk if you actually worked on the inverter while it was on, which isn't even dangerous if you are careful.

        You've never worked with an inverter while its on, have you? It can totally suck you into a temporal vortex if you even look at it while its on. I would never even consider it except under the most dire circumstances.

        And if you're that worried about the safety of cutting into a cold cathode, you could always use a shop vac to improvise a fume extraction system, in case you screw it up.

        Too risky. You could get sucked up by the vac, and then how would you get out? You wouldn't. Then what good will the monitor be to you?

        Or you could order a harder to find cold cathode that does not have the covering mentioned, or salvage one from a scanner.

        Okay, that's just nonsense. Everybody knows that all a scanner can do is make people's heads explode. [imdb.com]
    • by 6Yankee ( 597075 ) on Sunday December 11, 2005 @05:27PM (#14234841)
      Think of it as aiding natural selection.
    • Mercury is not that toxic. Arsenic is a lot worse and even that takes some effort to kill you or even make you sick. I was once playing around with a mercury tilt switch and put too much current through. The Mercury vapourised and blew out through a small hole in the glass. At the time I was terrified and looked up everything I could on mercury poisoning, but that was 20 years ago, and I have registered the slightest hint of mercury poisoning symptoms since.

      Mercury is more of a problem if it is a) in an
      • When I broke a thermometer (was shaking it and it just flew out of my hand and into a wall!) I read up on what to do... Most of the information I read said that you could ingest liquid mercury and not expect too much hassle, it would just pass through you (but don't make a habit of it! :). The thing to watch out for was the vapour, as that would get into your body a lot more readily.

        I think it gets to be a serious problem if you are breathing in the vapour over a long time.

        In my case, I got hold of some sul
      • > "I have registered the slightest hint of mercury poisoning symptoms"

        You sure have.

    • by Tim C ( 15259 )
      Top tip: capacitance is measured in farads, not volts; a borg really ought to know that.
  • How old? (Score:3, Insightful)

    by Jeff DeMaagd ( 2015 ) on Sunday December 11, 2005 @04:46PM (#14234678) Homepage Journal
    Those tubes are pretty long life, how often do they fail on average? I thought it was something like 50,000 hours, so something that fails in the first three years or so of average use (40 hours a week * 50 weeks of use a year = 2000 hours a year) should be pretty rare. If the display is too old, it might not be worth that much anyway as older LCDs can get pretty bad for colors, contrast ratio, viewing angle and such.

    They do dim with age though, which isn't a problem for me, I try to reduce the brightness anyway.
    • All of my LCD panels are turned to the minimum brightness and contrast for the environment I'm working in. However, recently (after about 2 years of use), one of my LCD panels started to have problems on startup - flickering light, inability to complete lighting up. I've had to leave that panel on (and turn off the energy saver setting that shuts the monitor off automatically), for fear that one of these days the problem will be so bad that no combination of turning the panel on/off will fix it. Evidentl
    • Re:How old? (Score:5, Funny)

      by mrak and swepe ( 799450 ) on Sunday December 11, 2005 @05:08PM (#14234771)
      how often do they fail on average?

      Once.
      • Actually, if it fails once, it is OK, all you need then is a strong desk lamp. When they fail a few times per second, it is maximally annoying... :-)

        Anyhoo, it is quite easy to get replacement bulbs of the right size and shape. No need to use purple case modder bulbs.
    • cold cathode just like domestic flourescents have a "half life", which means a light quoted as having a 10,000 hour lamp life will be half as bright in lumens at 10,000 hours, it will also be emitting different spectrum of light as it ages.

  • by gasmonso ( 929871 ) on Sunday December 11, 2005 @04:48PM (#14234689) Homepage

    Here's a little more info that laptop users might find useful and I stress "might". http://iantha.vectorstar.net/ccfl.html#replace [vectorstar.net]

    gasmonso http://religiousfreaks.com/ [religiousfreaks.com]
  • It'd be cooler... (Score:4, Interesting)

    by BushCheney08 ( 917605 ) on Sunday December 11, 2005 @04:55PM (#14234714)
    It'd be a lot cooler if you replaced the bulb with a blacklight instead (press cmd-opt-ctrl-8 on a mac for a simulation)...
  • by G4from128k ( 686170 ) on Sunday December 11, 2005 @05:00PM (#14234731)
    LCD backlights are seldom bright enough when I want to sit outside (I know, I know, outside is sooo unnerdlike but sometimes it's nice to sit outside while working at a coffee-shop). But why try to compete with the ultimate light source? If the back of the laptop lid could swing open or be removed, then the sun could flood in. A diffuser/polarizer on the back of the LCD would let the sun be the perfect outdoor backlight.
  • by doood ( 534531 ) on Sunday December 11, 2005 @05:00PM (#14234734) Homepage Journal
    Yes, I've been able to fix multiple different laptop screens this same way as well. IBM T21's T41's etc... Most laptop lcd are relativly easy to dismantale is you've got a sharp set of #000, #00, and #0 phillips screwdrivers. I found almost all my bulbs from http://lcdpart.com/ [lcdpart.com]. I found there prices to be really affordable as well, $10 for the 14"-14.5" bulb! You'd be surprised how easy this whole procedure is if you can solder a few wires. ;-)
  • by bogie ( 31020 ) on Sunday December 11, 2005 @05:08PM (#14234765) Journal
    "The cold cathode is incased in a plastic case to protect it and defuse the light. We will need to remove the casing very carefully. Most cold cathode tubes have mercury vapor in them this is very dangerous if it was broken. Avoided damaging the bulb at all costs as mercury vapor has been linked to brain damage and cancer."

    Sounds like fun! I also heard the best way to tell if a wire is live is to lick your finger and touch it. Don't forget to stand on one leg while you do it though! Otherwise you might get hurt.
  • by Anonymous Coward on Sunday December 11, 2005 @05:13PM (#14234798)
    Ok, some comments from somebody who works with cold-cathode lamps.

    First the mercury is pretty much a non-issue, it only escapes if you break the lamp and the ammount is miniscule anyway. As long as you are in a well ventilated area don't worry at all.

    Second the manufacturer fits high-performance cold cathode lamps, subsituting hobby grade lamps is going to give you terrible colour rendering (I've seen cheap lamps that were more pink than white), and also the light output will be _considerably_ lower.

    And last if you use the original inverter you are going to be overdriving the new lamp horribly. So the colour will suffer and the life will be affected (plus the lamps will run very hot indeed).

    These are not at all like incandesent lamps, the inverters are tuned to the lamp parameters and cheaper/different lamps are likely to not match the inverter very well at all.
  • Not that dangerous (Score:5, Insightful)

    by Flying pig ( 925874 ) on Sunday December 11, 2005 @05:17PM (#14234812)
    As my physics teacher used to say, if the things physicists work with are really as dangerous as that, why do physicists have above average life expectancy?

    The answer of course is that most of these hazards are serious for people who are exposed to them continuously as a result of work or environment (e.g. asbestos, radon.) Occasional exposure to a small amount of mercury is unlikely to do you a lot of harm; it might even kill a bacterial infection you didn't know you had. Working continuously in an environment containing detectable levels of mercury vapour could be very bad indeed.

    • As my physics teacher used to say, if the things physicists work with are really as dangerous as that, why do physicists have above average life expectancy?

      Probably because they know what they are doing, and take the necessary precautions. I don't think either of those things apply to random Slashdotters trying this, do you?

      • Probably because they know what they are doing, and take the necessary precautions.

        Hee hee. You've never hung out with physicists, have you? Have you ever seen what happens when someone who's spent four years studying GR and Quantum Mechanics tries to play engineer?

        Worst. Safety. Protocol. Ever. Just among the things I remember from my time in an atomic physics lab -- exposed 220V, shorts-n-sandals (as opposed to OSHA required long pants and steel-toed boots), random high-power lasers setting fire to
    • by deacon ( 40533 ) on Sunday December 11, 2005 @06:15PM (#14235037) Journal
      Exactly.

      Mercury and Asbestos hysteria is far out of proportion to the risk.

      This page on mercury

      http://www.theodoregray.com/PeriodicTable/Elements /080/index.s7.html [theodoregray.com]

      (scroll down) shows a guy sitting (floating) in a vat of it. My high school chemistry teacher used to demo mercury by putting a little puddle in each childs hand.

    • Mad as a hatter.. (Score:2, Interesting)

      by macjim ( 856503 )
      Mercury poisoning was the basis for the phrase "Mad as a hatter", and of course the character at the tea party in Alice in Wonderland. They used to steam top hats with mercury vapour, if I recall correctly, and after years of such work suffered brain damage. Not quite so likely with LCD backlights.
      • Re:Mad as a hatter.. (Score:2, Interesting)

        by GigsVT ( 208848 )
        Also it wasn't elemental mercury, which is basically inert to humans.

        One time at the high school I went to, a kid blew into a manometer and shot elemental mercury all over, they actually called hazmat and evacuated the building while they cleaned it up.

        Such a waste caused by ignorance.
    • by ortholattice ( 175065 ) on Sunday December 11, 2005 @06:50PM (#14235160)
      You may want to read about researcher Karen Wetterhahn [bris.ac.uk], who died after spilling a drop or so of dimethylmercury, on top of the latex gloves she was wearing. Her story gives me the willies.
      • Yes, Dimethylmercury has as much to do with mercury as alumina to aluminium, cyanates to cyanide, hydrogen to water, etc. It annoys me when people can't even get the most basic grasp of chemistry.
  • You know what you were thinking when you saw the poster's name:

    Bill! Bill! Bill! Bill! Bill Nye the Science Guy.
    [I know you can hear this song in your head]
  • "Those of us that have used LCD monitors for a while know that over time the backlight starts to dim and will eventually completely fail. Leaving you with some electronic scrap that you could sell on eBay for 35 bucks or so. Well for less than $20.00 and about a half hour of your time you can replace the backlight and rejuvenate that monitor to as good as new condition."

    ...I'll give you a grammar lesson. Let's start with run-on sentences:

    Those of us that have used LCD monitors for a while know that,

  • by Ancient_Hacker ( 751168 ) on Sunday December 11, 2005 @05:24PM (#14234831)
    A few words about that *deadly* mercury vapor:
    • Have you ever broken a fluorescent light?
    • If not, go do so right now.
    • Still here?
    • Of course you are.
    • the amount of mercury vapor in a four-foot fluorescent tube is about, hmm... lesse a pint's a pound, never eat anything bigger than your head, ..... >.
    • I ma ke the volume of a 4foot 1.25" diameter tube versus a 17 inch 0.15 inch tube as about 150 times.
    • So if you survived the overhead light breeaking, you're not going to be much worse off breaking a little LCD CCFL tube.

    Sheesh!

    Required disclaimer: When breaking fluorescent tubes, do so in an area with some ventilation. Do not huff the tube. Do not lick the insides of the tube.

  • by Z00L00K ( 682162 ) on Sunday December 11, 2005 @05:25PM (#14234833) Homepage Journal
    Some more details would be useful - but it is at least interesting to know that there is a possibility to repair for a cheap sum. Today the price of white LED:s are also starting to be acceptable so one may wonder if some white LED:s (powerful ones) may be of use. One version is the Luxeon Emitter [www.elfa.se] that is fairly bright and can be found in LED torches.

    Or a ramp of cheaper white LED:s may also do the trick.

  • DIY (Score:2, Interesting)

    by stewwy ( 687854 )
    If you can do it do it if you can't dont, I've fixed countless things using bits of tape and odd things I've found lying about,
    Best was a laptop, one of the first with a plasma screen given to me by my sisters boyfriend who had one on loan from the manufacturer ( begins with tosh.... ). He'd dropped it in the airport, his own stupid fault. he was throwing it out ( or hiding the evidence depending on your point of view :p )

    Two hours later and 10 bits of wire and a lot of fiddly soldering, I owned of th
    • > Mind you I know plenty of people who should be banned from owning any sort of tool

      Especially "that one", if you know what I mean :)
  • by FlyByPC ( 841016 ) on Sunday December 11, 2005 @05:34PM (#14234868) Homepage
    Turn the LCD panel, plus an overhead projector, into a projection TV [tomshardware.com].

    (I did it; it actually works quite well. I'm using it as my TV.)
  • Ugh (Score:4, Insightful)

    by Jeffrey Baker ( 6191 ) on Sunday December 11, 2005 @05:35PM (#14234869)
    As others have pointed out, the linked article is unreadable, barely informative, and likely to damage the environment and one's health. So here's a better idea: if you want to reinvigorate an aging LCD monitor, why not just remove the back altogether, and mount the panel on a nice white LED lightbox? It seems like it would be a big improvement.
  • by zymano ( 581466 ) on Sunday December 11, 2005 @06:22PM (#14235057)
    We need to pass a law to make these things more easily fixable.

    Shady business practice not letting you fix things.

    Maybe with a law ?
  • The surplus market.

    A 30 second search turns up this lamp+inverter.

    http://www.mpja.com/productview.asp?product=14840+ LA [mpja.com]

    Search a bit longer to find one the right size :)

  • Damn (Score:2, Funny)

    by baKanale ( 830108 )
    Now all those people selling broken LCD's on eBay will be able to fix them! That means I won't be able to use them to make my DIY LCD Projector [slashdot.org]

    It is kinda funny that two articles involving DIYs on LCDs came out within one week of eachother.
  • Laughable.. (Score:5, Informative)

    by jskline ( 301574 ) on Sunday December 11, 2005 @06:37PM (#14235114) Homepage
    I get a kick out of the seemingly sarcastic sounding "how do I fix this" things that I see here, and have seen in many other places. Fact is that with "tech" moving at such a pace these days, people (those with lots of ready-cash) are more likely to just dump this stuff into the trash (and landfills) and just go buy something new, rather than fix it.

    I have been doing this sort of thing now since something like 1998 with relative ease. The only hassle has been scrounging up the cold cathode tubes that are large enough to cover the screens like the originals. Some will note that these have been conspicuously absent from the after-market parts shelves up until a couple years ago when it became fashionable to "light up" your box with colored lights. You quite literally had to know how to find them prior to this because they did not want them to be found. Any technician worth his salt knew that if you could replace the tube (and it wasn't hard at all to do), you could revive a computer or screen and make some money rather than having the user tossing this item into the landfills and spending whopping amounts of cash on "new models". (Yea, thats an accusation about the major OEM players; NEC, Toshiba and Sanyo; IMO)

    As for the brightness issue... If you've replaced the tube and it's still dim, it's nothing more than the capacitors failing on your DC to AC converter boards. The caps are rated so close to tolarance in manufacture that with heat buildup and time, they fail prematurely. I've successfully pulled the boards and replaced the caps to bring them back to life assuming the transistors and IC have not failed. The brightness issue is nothing more than deviating the PWM (pulse width modulation) of the AC out to the tube. This change in PWM changes the resonance for the tube's circuit and hence it's brightness level is related to the PWM circuit efficiency. When the caps become leaky and dry, the circuit can no longer approach its normal or calculated PWM value or resonance, and hence your screen no longer can get as bright as it used to. Color temperature changed screens are the same issue. The cc tube is just more sensative to the current PWM and is lighting up in a particular color temperature; usually a brown or reddish hue.

    Theoretically these LCD screens can last for many, many years if you want to simply replace these tubes and fix their circuits when they fail. Based on past history and my direct attempts to get these cc tubes and parts from several OEM's directly; replacing the entire LCD screen as a complete part; at a hefty price I might add; is generally your ONLY choice. More often than not, the replacement LCD panel cost more than the whole monitor did new!!!

    I expect however that replacing the cc tubes as a standard repair will not be available because the folks manufacturing the LCD screens seem to control the access and if there is limited or no access to the parts, you only have access to "NEW" screens... or obviously new monitors!

    Your market... you decide!!

    Cheers;
  • hair-dryer (Score:2, Interesting)

    my old 15' lcd went very dark and dimmed more and more until it refused to light up at all. i thougt oh fsck! now i have to use my old crt display again! (it had some 'funny' colour-effects).
    but then i discovered something: when i turned up the heating, the lcd started to work again (it stood on a desk right over the radiator).
    because i didn't want to make a sauna of my room i used a hair dryer to warm the disply up (that used to take 5-10 minutes). i continued to use that display for over a year :-)
    sinc
  • Been there done that (Score:3, Informative)

    by amigabill ( 146897 ) on Sunday December 11, 2005 @08:36PM (#14235616)
    It's pretty fun to do. A friend didn't want to fix his laptop himself but did want to save some money, so a few of us got togther and replaced his LCD backlight for him. It's really cool to see how many layers of various films are stacked up in there, as at least on this one we had to prety much completely disassemble the panel to get to the light tube.

    My friend got slightly the wrong tube length, so the two ends are a bit dark. There's a coupel fingerprints inside the LCD now, and someone's eyelash. If you end up seriously tearing the thing apart liek we did, get some latex gloves or somethign to help with the fingerprints, and try not to shed during the operation. :)
  • I've got a Ceiva2 ( http://www.rangat.org/rthille/Computer/Ceiva2/inde x.html [rangat.org] ) of which the backlight has failed. I tried my Fluke DMM to check the voltage out of the inverter, but the frequency is too high. Anyone have a good way to decide (before I go buying inverters or tubes) which is the part I need to replace?

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