The replacement light tunnel looks like it's constructed much better than the previous one. There is more adhesive, and the 4 mirrors interlock with each other so I don't think they're going anywhere even if the glue fails. Toshiba probably fixed that flaw in the design.
After replacing that, my picture went from 100% dim to about 30% dim (top 30% dark, rest OK), so I opened the whole thing up again and tightened the screws on top of the prism assembly. My unit had regular screws instead of Allen and blue paint instead of red, but I was still able to fix it.
Thanks for the tips - I doubt I could have fixed it myself without them!
Thanks ,so much to everyone, with all your interesting info.
Lucky ....Toshiba did help me repair my set....100% parts and 50% of the labor. My finaly cost was about $65.00 I hope it is an upgraded light engine, that should be more reliable than the original. Time will tell.
Hi I have to replace the light tunnel and I have no idea how. I took the lamp out and then what do I do? I read Skyhawks post and behind the lamp is the light tunnel?? I have the Toshiba 44nhm84. Does anyone know the steps to replacing this light tunnel??
You have to get way in there - take the screen off - then take off the large metal chassis holding the light stuff on the right side. The lamp shines into the light tunnel, but you have to take most of the thing apart to get at it.
I am having the same problem. I have taken the screen off. I cannot get the metal chasis off. I have removed the two screws at the front of the chasis and pushed it off the platic pin in the back. Something is still holding in the backside but I cannot make out what's still holding. Any help would be appreciated. thanx
Well I figured it out. I removed the light tunnel. When I removed the light tunnel one of the mirrors in the prism fell right out and broke on the floor. It sucks that it broke on the floor but at least I found the problem(hopefully). I have ordered a new light tunnel from the link above. 55USd compared to 185Cad her in my city. Thanx for all your help and all the savings.
Hi guys - thanks a lot for this thread. I've had the same problem and was on my way to replace the lamp (at the recommendatin of my local retailer) until I read about the light tunnel problem.
Like chochi_ca, I've got the chassis unbolted in front, but something is holding it back - looks like a metal tab that goes down to the base of the tv, but I can't figure out how to unhook or unbolt it. Could chochi_ca or anyone else help me out with this final step so I can get at the light tunnel?
Thanks Adam2. I'll take another look tonight. It's really hard to see what's holding the tab down since the light box is in the way (directly underneath the metal housing) and I can only bend the metal housing so far to see what's in there. I'll look around and see if I can find that screw.
I figured there must be a way to do it, but I didn't want to break anything by messing around in there...
I'm thinking back several months, but if I recall, you had to take the entire light/electronics/housing thing off of the base to get at the screw holding that tab on there.
I was wondering about that. I tried but there's just no way to reach in and get at the tab. I'll take a run at it this weekend.
I feel like I'm disassembling the whole thing just to fix a simple problem. Looks like Toshiba weren't expecting the light tunnel to be a problem since they made the damn thing so hard to get at. This explains the several hundred $$ labor charges people have been facing when they get the service techs to replace it...
Thanks for the continued pointers Adam2, and I'll let you know what success I have...
I too have the left side shadow problem. Bought a replacement lamp for $250 on ebay to no avail. Called a local Toshiba authorized repair center who told me that the light engine would cost $1000 to repair. The TV is less than 2 years old and im sick to my stomach.
My question here is...Is there a difference between the light "tunnel" part theis forum refers to at $60 and the light "engine".
I should never have smacked the tv when I got upset. This is probably my own fault. Thinking of just biting the bullet and buying another 42" LCD or Plasma at Costco for $1000.
I doubt your problem is the light engine. That's the whole bunch of electronics that does all the light and picture I believe. The "light tunnel" is about a 2" by 3" metal part with a small "tunnel" of mirrors that focuses the light into the color wheel. The common problem that most people in this thread are seeing is due to the cheap glue they used causing one of the mirrors to fall and block part of the light in the tunnel. Once you get at the part, you can either glue the mirror back in yourself or get a new light tunnel like I did for around $60. The replacement part has interlocking mirrors and way more glue than the one that came with my TV.
Adam2 said: I doubt your problem is the light engine. That's the whole bunch of electronics that does all the light and picture I believe. The "light tunnel" is about a 2" by 3" metal part with a small "tunnel" of mirrors that focuses the light into the color wheel. The common problem that most people in this thread are seeing is due to the cheap glue they used causing one of the mirrors to fall and block part of the light in the tunnel. Once you get at the part, you can either glue the mirror back in yourself or get a new light tunnel like I did for around $60. The replacement part has interlocking mirrors and way more glue than the one that came with my TV. http://www.partstore.com/Part/Toshiba... It's definitely not an easy repair job, but I was able to do it over two afternoons, and I'm not all that handy.
Thanks Adam - I'm pretty handy but would love to get the repair PDF that someone mentioned on this thread or a little more "step by step" from Skyhawk :) our resident pro.
Yep - it's the mirror. I finally got to it. It's a crappy little sliver of mirrored glass about an inch long by 1/4" wide, and it just dropped off the inside of the light tunnel. I glued mine back using an adhesive good for up to 400F. If that doesn't hold it, I'll buy the replacement part. Jay - I can't reassemble it until the glue has cured for 24 hours. When I do I'll take photos of the reassembly and see if I can do a guide to what I did so you can have a look. Might take me a few days to get it done, but it'll save you some time (I spent some time puzzling out what to remove). It does take a bit of work to get to the mirrors - it's almost like they deliberately made the part most likely to fail the hardest to get to. I'll post again in a couple days when I've got the guide ready. Andy
Here is a link to a zipped version of the service manuals (circuit diagrams etc). I bought it earlier this year when I started having problems, now comes to you all at the low price of free. It's about 15 MB (contains 2 PDF files).
Thanks for that, Tom, the exploded view on page 15 of the Prelim pdf is very useful.
When I put my pix and commentary up I'll reference the part numbers in the exploded view.
I'm going to try to reassemble the set tonight. I should be able to post my photo guide a bit later this week - depends on how much free time I can get.
Thanks gobbeg. I called my local repair shop who basically told me it wasnt worth it and that I should replace the whole light engine. 2nd place that wants to replace the whole engine. Looking forward to your pictures and commentary.
OK Gang, here we go. I've put my guide and photos in a pdf. It's a 27MB file because of all the photos in it. You're probably not going to want to print it out in color unless you have a really good printer ink budget. I don't have anywhere to post it, so any admins reading, how do I post an attachment to the forum? In the meantime, anyone wanting it directly can PM me with your email address. Andy.
When you get there you'll see a page with the link to the file. It was a bit glitchy when I tried to download it just by left-clicking on it, but worked fine when I right-clicked and then clicked "Save target as..."
It's 27MB, so make sure you have enough bandwidth available.
I had written this darn TV off completely (sitting in a spare room in my basement). I gave the tutorial a whirl, and low and behold the mirror (same one as in the tutorial) had dropped. The only high temp glue I could find (greater than 300 degrees F) was in fact Threadlocker (450 F), so I will give that a try. Any advice there would be helpful, but I guess if it doesn't work, the $60 light tunnel shouldn't be too much of setback.
Threadlocker does NOT work...found some "loctite" brand "extreme repair" glue at the home depot (400 F rated)...just fired up the TV (24 hours later) and it looks as good as new. Now my wife asks what the heck we are going to do with it...now we have 3 HDTVs....
Tom - thanks for posting the tutorial up - I don't have a website where I can park it, and the Freesender allows a maximum posting lifespan of 1 month.
On the glue front, I used Elmer's Probond. I just went down the line of glues at my local hardware store, checking for bonding glass and metal, and looked for the highest temp I could find. A week later, my TV is still working fine, but if the glue goes again I'll just get the replacement part.
This thread saved me from junking my TV, so thanks to all the OP's who explained the problem.
gobber..............I have posted your tutorial , using tomolly's site.
What an excellent tutorial . Toshiba could use someone with your talent.
I had no idea my thread would go this far, this long. I have down loaded you tutorial for future reference. So far my set works great, after Toshiba replaced the light engine. I hope it has been retrofited so I won't have problems in the future. If I do, I can repair it.....THANKS TO YOU ...gobber
Wow, thanks a ton, Skyhawk. My DLP wound up with BOTH the dropped mirror and the mirror/prism thing out-of-alignment.
I bought a new light tunnel from partsearch for about $60.
http://www.partstore.com/Part/Toshiba/Toshiba/44NHM84/Toshiba/Toshiba/72796068/New.aspx
The replacement light tunnel looks like it's constructed much better than the previous one. There is more adhesive, and the 4 mirrors interlock with each other so I don't think they're going anywhere even if the glue fails. Toshiba probably fixed that flaw in the design.
After replacing that, my picture went from 100% dim to about 30% dim (top 30% dark, rest OK), so I opened the whole thing up again and tightened the screws on top of the prism assembly. My unit had regular screws instead of Allen and blue paint instead of red, but I was still able to fix it.
Thanks for the tips - I doubt I could have fixed it myself without them!
Thanks ,so much to everyone, with all your interesting info.
Lucky ....Toshiba did help me repair my set....100% parts and 50% of the labor. My finaly cost was about $65.00 I hope it is an upgraded light engine, that should be more reliable than the original. Time will tell.
The horizontal lines don't line up on my picture. Could this be from the light tunnel?
Dan
Hi I have to replace the light tunnel and I have no idea how. I took the lamp out and then what do I do? I read Skyhawks post and behind the lamp is the light tunnel?? I have the Toshiba 44nhm84. Does anyone know the steps to replacing this light tunnel??
thanks,
chris
You have to get way in there - take the screen off - then take off the large metal chassis holding the light stuff on the right side. The lamp shines into the light tunnel, but you have to take most of the thing apart to get at it.
I am having the same problem. I have taken the screen off. I cannot get the metal chasis off. I have removed the two screws at the front of the chasis and pushed it off the platic pin in the back. Something is still holding in the backside but I cannot make out what's still holding. Any help would be appreciated. thanx
Well I figured it out. I removed the light tunnel. When I removed the light tunnel one of the mirrors in the prism fell right out and broke on the floor. It sucks that it broke on the floor but at least I found the problem(hopefully). I have ordered a new light tunnel from the link above. 55USd compared to 185Cad her in my city. Thanx for all your help and all the savings.
Hi guys - thanks a lot for this thread. I've had the same problem and was on my way to replace the lamp (at the recommendatin of my local retailer) until I read about the light tunnel problem.
Like chochi_ca, I've got the chassis unbolted in front, but something is holding it back - looks like a metal tab that goes down to the base of the tv, but I can't figure out how to unhook or unbolt it. Could chochi_ca or anyone else help me out with this final step so I can get at the light tunnel?
Cheers,
Andy
I remember that one being a pain too. There's a screw holding that tab down to the base, it's just hard to get at if I recall.
I remember that one being a pain too. There's a screw holding that tab down to the base, it's just hard to get at if I recall.
Thanks Adam2. I'll take another look tonight. It's really hard to see what's holding the tab down since the light box is in the way (directly underneath the metal housing) and I can only bend the metal housing so far to see what's in there. I'll look around and see if I can find that screw.
I figured there must be a way to do it, but I didn't want to break anything by messing around in there...
I'm thinking back several months, but if I recall, you had to take the entire light/electronics/housing thing off of the base to get at the screw holding that tab on there.
I was wondering about that. I tried but there's just no way to reach in and get at the tab. I'll take a run at it this weekend.
I feel like I'm disassembling the whole thing just to fix a simple problem. Looks like Toshiba weren't expecting the light tunnel to be a problem since they made the damn thing so hard to get at. This explains the several hundred $$ labor charges people have been facing when they get the service techs to replace it...
Thanks for the continued pointers Adam2, and I'll let you know what success I have...
I too have the left side shadow problem. Bought a replacement lamp for $250 on ebay to no avail. Called a local Toshiba authorized repair center who told me that the light engine would cost $1000 to repair. The TV is less than 2 years old and im sick to my stomach.
My question here is...Is there a difference between the light "tunnel" part theis forum refers to at $60 and the light "engine".
I should never have smacked the tv when I got upset. This is probably my own fault. Thinking of just biting the bullet and buying another 42" LCD or Plasma at Costco for $1000.
Jay
I doubt your problem is the light engine. That's the whole bunch of electronics that does all the light and picture I believe. The "light tunnel" is about a 2" by 3" metal part with a small "tunnel" of mirrors that focuses the light into the color wheel. The common problem that most people in this thread are seeing is due to the cheap glue they used causing one of the mirrors to fall and block part of the light in the tunnel. Once you get at the part, you can either glue the mirror back in yourself or get a new light tunnel like I did for around $60. The replacement part has interlocking mirrors and way more glue than the one that came with my TV.
http://www.partstore.com/Part/Toshiba...
It's definitely not an easy repair job, but I was able to do it over two afternoons, and I'm not all that handy.
Thanks Adam - I'm pretty handy but would love to get the repair PDF that someone mentioned on this thread or a little more "step by step" from Skyhawk :) our resident pro.
If anyone has this, I would love to get a copy..
Thanks,
Jay
Yep - it's the mirror. I finally got to it. It's a crappy little sliver of mirrored glass about an inch long by 1/4" wide, and it just dropped off the inside of the light tunnel. I glued mine back using an adhesive good for up to 400F. If that doesn't hold it, I'll buy the replacement part. Jay - I can't reassemble it until the glue has cured for 24 hours. When I do I'll take photos of the reassembly and see if I can do a guide to what I did so you can have a look. Might take me a few days to get it done, but it'll save you some time (I spent some time puzzling out what to remove). It does take a bit of work to get to the mirrors - it's almost like they deliberately made the part most likely to fail the hardest to get to. I'll post again in a couple days when I've got the guide ready. Andy
Great! A guide with pictures would be sweet! You can post it here!
Here is a link to a zipped version of the service manuals (circuit diagrams etc). I bought it earlier this year when I started having problems, now comes to you all at the low price of free. It's about 15 MB (contains 2 PDF files).
http://www.chrisdicockers.com/44NHM84...
enjoy!
-Tom
Thanks for that, Tom, the exploded view on page 15 of the Prelim pdf is very useful.
When I put my pix and commentary up I'll reference the part numbers in the exploded view.
I'm going to try to reassemble the set tonight. I should be able to post my photo guide a bit later this week - depends on how much free time I can get.
Andy
OK, all done, reassembled, and it works great. Black shadow is gone!
I took quite a few pics of the work in progress. Give me a few days and I'll get it organized with commentary and post it up here.
Andy
OK Gang, here we go. I've put my guide and photos in a pdf. It's a 27MB file because of all the photos in it. You're probably not going to want to print it out in color unless you have a really good printer ink budget. I don't have anywhere to post it, so any admins reading, how do I post an attachment to the forum? In the meantime, anyone wanting it directly can PM me with your email address. Andy.
Send the PDF to the editor of this site and see if he will post it for you.
Thanks Larry - I just put it up on Freesender, one of the free upload/download services mentioned in the Featured Blog on the front page.
Anyone that wants it can dowload it by going to this page: http://www.freesender.com/DL/2C26949E99
When you get there you'll see a page with the link to the file. It was a bit glitchy when I tried to download it just by left-clicking on it, but worked fine when I right-clicked and then clicked "Save target as..."
It's 27MB, so make sure you have enough bandwidth available.
Andy
Nice tutorial gobbeg. I went ahead and downloaded it and then re-uploaded (looks like your link will expire August 5th 2007) the file to here:
http://www.chrisdicockers.com/Amateur...
I had written this darn TV off completely (sitting in a spare room in my basement). I gave the tutorial a whirl, and low and behold the mirror (same one as in the tutorial) had dropped. The only high temp glue I could find (greater than 300 degrees F) was in fact Threadlocker (450 F), so I will give that a try. Any advice there would be helpful, but I guess if it doesn't work, the $60 light tunnel shouldn't be too much of setback.
-Tom
Threadlocker does NOT work...found some "loctite" brand "extreme repair" glue at the home depot (400 F rated)...just fired up the TV (24 hours later) and it looks as good as new. Now my wife asks what the heck we are going to do with it...now we have 3 HDTVs....
thanks to everyone on this thread for the input!
-Tom
Tom - thanks for posting the tutorial up - I don't have a website where I can park it, and the Freesender allows a maximum posting lifespan of 1 month.
On the glue front, I used Elmer's Probond. I just went down the line of glues at my local hardware store, checking for bonding glass and metal, and looked for the highest temp I could find. A week later, my TV is still working fine, but if the glue goes again I'll just get the replacement part.
This thread saved me from junking my TV, so thanks to all the OP's who explained the problem.
- Andy
gobber..............I have posted your tutorial , using tomolly's site.
What an excellent tutorial . Toshiba could use someone with your talent.
I had no idea my thread would go this far, this long. I have down loaded you tutorial for future reference. So far my set works great, after Toshiba replaced the light engine. I hope it has been retrofited so I won't have problems in the future. If I do, I can repair it.....THANKS TO YOU ...gobber
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