Guys, this is really depressing. About a year ago I had a glycol leack on my marquee. Spent the next months cleaning, buying, shipping, and swapping different boards. 2 weeks ago I gave up after swapping more then 6 boards. I saw a nice new marquee on the avs ad for sale for a good price. I jumped in. Received it 2 days ago, turned it on and waahhh finally my theater is on again. Yesterday I stayed late doing color calibration and heard my newborn crying. Went to check on him and Left the marquee at contrast 80 with a white window covering 70% of the screen on. 25min later, I returned to the theater and there was no light on the screen! Restarted the PJ and still no pic. Looked into the tube, the B/G were off and the green tube was flashing dimly. Now I have 2 broken marquee at home. I will start exchanging parts starting tonight. But guys, I have been doing this for several months now. This is getting really tiresome. CRTs are great, but really requires tons of time and patience. Something you loose with time....

I feel for you, I have certainly been in that situation more times than I care to count.

Dude! I feel your pain,I had my barco down for about three months,got tired and sick of it.I just wanted to watch a movie,was ready to throw in the towel until I started using my backup 720p lcd.That's when I new why I got into crt and nothing else would do.With alot of help from forum members and curt I was up and running eventually.
All I can say is hang in there,if there are any positives from downtime,well for me anyway,was the fact that I got to know the machine alot better and am able to sort out minor issues on my own.
Hope you sort things out soon so you can enjoy that crt goodness again:)

Dave

Dude! I feel your pain,I had my barco down for about three months,got tired and sick of it.I just wanted to watch a movie,was ready to throw in the towel until I started using my backup 720p lcd.That's when I new why I got into crt and nothing else would do.With alot of help from forum members and curt I was up and running eventually.
All I can say is hang in there,if there are any positives from downtime,well for me anyway,was the fact that I got to know the machine alot better and am able to sort out minor issues on my own.
Hope you sort things out soon so you can enjoy that crt goodness again:)

Dave

The funny part is I went through something similar. I bought and sold an JVC RS2 and a Marantz 11s2 in the last months. That just boosted my efforts to repair my CRT :). But all this added to my hobby expenses. I mean after 8 months, I am back to zero with a lots of $$$s waisted.

Guys, this is really depressing. About a year ago I had a glycol leack on my marquee. Spent the next months cleaning, buying, shipping, and swapping different boards. 2 weeks ago I gave up after swapping more then 6 boards. I saw a nice new marquee on the avs ad for sale for a good price. I jumped in. Received it 2 days ago, turned it on and waahhh finally my theater is on again. Yesterday I stayed late doing color calibration and heard my newborn crying. Went to check on him and Left the marquee at contrast 80 with a white window covering 70% of the screen on. 25min later, I returned to the theater and there was no light on the screen! Restarted the PJ and still no pic. Looked into the tube, the B/G were off and the green tube was flashing dimly. Now I have 2 broken marquee at home. I will start exchanging parts starting tonight. But guys, I have been doing this for several months now. This is getting really tiresome. CRTs are great, but really requires tons of time and patience. Something you loose with time....


I feel you pain. I spent more time fixing my Marquee than actually watching it. I now have an RS2 and a Radiance in my theatre, it's worked perfectly since it's purchase from AVS 7 months ago and I 've watched more movies on it than I ever did on my CRT. The picture may not be quite as good as the Marquee (Heavily modded 9500 Ultra) but it works every time I turn it on. Could it be better...yes but I'd had enough of F-ing around with the Marquee trying to keep it working.

Chris.

I dont know how there are so many Marquee issues, My three work fine and tho only reason I dont watch them much is the fun i am having replacing parts on them. I had bad luck with the first one i got, worked at the persons home drove 5 hours home and it was dead(something must have fell onto the mother board and sorted something out) but oter than the stupid things i have done my self I have had no problems for the lat two years.

Athanasios

k, some good news, I managed to get a pic on the G/B Tube!!!
I explain, I tried swapping the CLM/VIM, nothing changed.
There was no light on the front of the LVPS so it must be working fine.
All CLM LED shows ok.
I then decided to unplug each tube after the other. I first disconnected the power from the green tube(By detaching the rounded bayonet) nothing changed. I did the same for red and VOILA!!!! I got a pic on the Green and blue tubes!! :D :D
k, So red tube must be F*&*cking things up. I took over cover of neck board and noticed some weird connections

Check the connections. I highlighted the differences betwen the RED and the 2 other tubes. Is it possible that the neckboard was modded, hence different placement of connections?

Went to check on him and Left the marquee at contrast 80 with a white window covering 70% of the screen on. 25min later, I returned to the theater and there was no light on the screen! .. why would you leave ANY CRt running with contrast that high for 25 minutes?

I dont know how there are so many Marquee issues, My three work fine and tho only reason I dont watch them much is the fun i am having replacing parts on them. Athanasios yeah I don't get it either? Maybe it's just amatuer hands at work.;)
If your buying a surplus machine you can just plop it down and expect it to run perfectly. There are certian things that have tobe done to insure reliability and once they're done the marquee's are solid. I know one thing, I've sold over 50 of these machines in 5 years and had almost zero problems, requiring just a simple board or power supply swap in a few cases, and that after years of use.


Check the connections. I highlighted the differences betwen the RED and the 2 other tubes. Is it possible that the neckboard was modded, hence different placement of connections? The red is original, the Blue and Green tubes have been replaced with a Barco pin-out style tube and those VNB's are modified.

Wait, those are MP modded VNB's.
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=131577&d=1233156940

Can you look closely at the RED VNB and see if it has a hole in the same place that the white G2 wires is conected on the Green and bleu. The red is conected into the "KEY" part of the Tube. Or take a close up of the red VNB at a nice straight on angle so we can get a look at all the pin placements.
the blue and green could also be LUG's.

it also looks like the Green VNB cage is grounded to the Ground wire from the VDM and covered with black electrical tape? why?
I would make sure the ground wire from the VDM is a straight line to the chassis and the Green braided cable goes to the rear heat sink when its in the closed posistion.

Also connect the black flat ground wire back onto the raised ground connector on the VNB like the green and blues.

it also looks like the VDM and SWA board have been cap upgraded, I wonder why the CVA wasn't done? that one shows the most improvement in performance on a marquee.

I was going to say swap out the VNB's but you cant do that if the red is different, you said you have another marquee? If those VNB's are like the reds
with no hole in it for the G2 line then swap one of those out. the OVER-I circuit on the VNB might be triping the blanking circuit possibly. I forgot if it just shuts of HV or brings the +/-85 line to full 85 to blank out the tube.
I bet its the red VNB though since you said the G?B light up when the HV lead for the red is pulled out.

Curt could help more than I though....

Athanasios

Athanasios,

I looked at the RED VNB and it have a hole on the upper pins like the G/B VNB. Actually all the VNB on this PJ are exactly the same is modded. Hence I am surprised why the different ways of connection.

I inserted the black tape temporary just to keep things in place :)

Yesterday I removed the VNB from the red tube and placed my old "non modded" VNB (without a whole on one of the pins). I connected the VNB to the tube in the same way as seen on the PIC and the Tube didn't light up. ie: When you connect the PJ to power, usually the 3 tubes have a very dim light on the back even when not powered. the G/B were lit but not the red. so the problem remained. I swapped in my old red tube with the old VNB, connected them to the PJ and I did get that light back. So I think there is a problem with either the red tube or the Red VNB. But since I tried my old VNB andthis didn;t work, then the problem should be the red tube. Unless the VNB was wired uncorrectly in the first place, and I need to replace the red VNB with a modded VNB. something I still haven't tried. I don't want to try and swap red with the new G/B VNB since I don't know what the red tube accept and what pins to wire.

Those are not MP's mods on those VNBs! They do look very lightly moded by someone, but, not MP!

Athanasios,

I looked at the RED VNB and it have a hole on the upper pins like the G/B VNB. Actually all the VNB on this PJ are exactly the same is modded. Hence I am surprised why the different ways of connection.

I inserted the black tape temporary just to keep things in place :)

Yesterday I removed the VNB from the red tube and placed my old "non modded" VNB (without a whole on one of the pins). I connected the VNB to the tube in the same way as seen on the PIC and the Tube didn't light up. ie: When you connect the PJ to power, usually the 3 tubes have a very dim light on the back even when not powered. the G/B were lit but not the red. so the problem remained. I swapped in my old red tube with the old VNB, connected them to the PJ and I did get that light back. So I think there is a problem with either the red tube or the Red VNB. But since I tried my old VNB andthis didn;t work, then the problem should be the red tube. Unless the VNB was wired uncorrectly in the first place, and I need to replace the red VNB with a modded VNB. something I still haven't tried. I don't want to try and swap red with the new G/B VNB since I don't know what the red tube accept and what pins to wire.


Do not use another VNB!!!! Connect the red the same as the G/B tubes!!!!

EDIT Actually look on the bell of the tube to tell us what the sticker on the tubes say. i hope you didn't fry a tube, but i think the conector that you hooked the G2 on the red doesnt have a connection on an LUG.

http://homepage.mac.com/nashou.66/.Pictures/Marquee%20Upgrade%20Pictures/Thomas%20Pin%20out.jpeg

Those are not MP's mods on those VNBs! They do look very lightly moded by someone, but, not MP!

They are MP moded VIMs, look att he potting on the 4 inductors he chaged out and the white cyinider/rubber that is filled with potting next to the op amp, thet is the power supply for the +/- 5 volt rails. I have a set and those are MP VNB's.

Athanasios

The RED tube is 09 type unlike the rest 07s so G2 was in the right pin. But then again, The 3 neckboard are the same, shouldn't the RED neckboard have different resistors placement?
Anyways I took out the lense on the red tube yesterday and OMG The trube front glass was broken & glycol reached inside the tube! Maybe something was wrong during shipping, since I really doubt a White pattern can cause glass breaking... I will try to swap in my old red tube (rarely used with 0 wear) from my previous leacking housing and insert it in the new one. Since olny the tube was brocken but the bellow and assembly seems ok. But is there a good way to confirm housing impermeableness before inserting the tube? Don't want a third leak...

Here is the procedure for removing the below without damaging it.

http://www.curtpalme.com/Marquee_LC_removal.shtm

Also I am trying to get a company to make new belows if you need them join in the cause here.

New Bellow Manufacture (http://www.curtpalme.com/forum/viewtopic.php?t=12052&start=0&postdays=0&postorder=asc&highlight=)

Athanasios

Originally Posted by THE_COW_IS_OK

" Maybe something was wrong during shipping, since I really doubt a White pattern can cause glass breaking... "

A white pattern that doesn't cover the whole tube face can cause uneven heating which can cause the glass to break. It has happened to me, too.

Scott

Originally Posted by THE_COW_IS_OK

" Maybe something was wrong during shipping, since I really doubt a White pattern can cause glass breaking... "

A white pattern that doesn't cover the whole tube face can cause uneven heating which can cause the glass to break. It has happened to me, too.

Scott

This Is good to know!!!

Athanasios

where did you buy the PJ? was it the one advertised here? thanks.

News Updates:

Just when I thought I saw the worse with CRT, I was in for a new surprise: I spent the past 2 days inserting my old and good red tube into the new marquee housing.
I turned on the PJ again and I saw sparkles on the top of the GREEN housing to one of the screws with a buzzing sound. Turned of the PJ immediatly. Disconected ALL cables going to Green and Red tubes and turned on again. This time the PJ turned on normally but but with no picture on the blue tube. Can this get any worse??

Can this get any worse?? only if you keep working on it :)

only if you keep working on it :)

Haha, well I thought several times seriously about sending this PJ to a professional for repair. But shipping and Import/export formalities alone would cost me about 1800$. (half what I paid for the PJ!). Add in repair/parts costs and I might be better of buying a 3rd PJ :D

Anyways, there are 3 last stuff I would like to do before declaring defeat:
Swapping: HVPS/LVPS/Main board. The LVPS is not showing any light on the front LED but it can still be damaged I guess.

You had an HV leak that maybe took out a board like the HDM or A VNB. You need to isolate that HV leak first. you said it was on the green housing, disconectt he HV lead from the Green and try to fire it up, look to make sure the H-fail isnt on, but it could still be that board. try another HDM witht he green no connected to the HV. f it works then you need to replace that Greens HV lead, try looking close for any cracks in the wire a small pin hole will do it.

Athaansios

You had an HV leak that maybe took out a board like the HDM or A VNB. You need to isolate that HV leak first. you said it was on the green housing, disconectt he HV lead from the Green and try to fire it up, look to make sure the H-fail isnt on, but it could still be that board. try another HDM witht he green no connected to the HV. f it works then you need to replace that Greens HV lead, try looking close for any cracks in the wire a small pin hole will do it.

Athaansios

With only the blue gun connected, I replaced the HDM with an old one I have. When I turned the PJ on, the light on the back of the tube (on the neck) get stronger but still no picture on the tube face.... (Note: I am not sure my old HDM works anyways so take this with grain of salt). Anyways, I also replaced today the motherboard beneath the tubes. And now I got a Vertical/Horizontal LED error lit on the CLM. And the fun continue....

f it works then you need to replace that Greens HV lead, yup, almost certainly the leak is at the anode lead. The old style leads with the loose fitting boot are awful. you can repair them sometimes by cleaning really well with Alchohol and Q-tip, then filling all the gaps with Black RTV but it doesn't always fix them.
I have enough of the newer leads here that when I see a tube with the old ****** wires I just replace it right away.

Any updates?

Nashou

Haha, yeah. AWB ready and PJ chassis going to curt :)

Haha, yeah. AWB ready and PJ chassis going to curt :)


AWB? Whats that?

Athanasios

AWB? Whats that?

Athanasios

AWB = Airway bill. Sorry about confusion...

guys, my marquee returned from repair and am facing new issues.
The horizontal dynamic convergence on the blue tube is not working properly. I can move the raster all over the blue tube from help/alignment setup. I can also properly adjust the dynamic convergence vertically but when I try to move it left/right in convergence menu, I get the green crosshatch moving instead of the blue one and in opposite direction of my arrows! Displacement is seriously limited as well especially off center. any idea how to fix this?

Tkx, Sam.

Just catching up on emails this week, I'll respond there as well, but from the sounds of it, you either have your H deflection yoke connectors plugged into the wrong HDM cables, or you've reversed the convergence yoke cables between tubes. I've done that here as well, spend hours the first time trying to 'repair' a problem that wasn't there. :)

Thanks curt, I double checked my connection and they are k.
Should I take out the blue tube and check the yokes placement?

Nevermind problem fixed by swapping convergence board :D

my 9500LC is alive again! (after a year downtime).
I worked on setting things up and found out surprisingly that my H10L lenses have much better focus on center then HD10F. Also found out a lot of variation in performance between lenses of the same model.....


Also wanted to thank all those who helped me through this in this thread!

That convergence board worked here. If you want to pull it off the heatsink and send me the PC board, I'll repair it at no charge.

Also found out a lot of variation in performance between lenses of the same model.....
I would double check Schemphlug and make sure it's correct.
Congrats on getting it running, everyone loves a happy ending:)

I would double check Schemphlug and make sure it's correct.
Congrats on getting it running, everyone loves a happy ending:)

This variation among same model reminds me of when I was searching for a L pro serie lenses for my canon SLR. I swapped 3 lenses before I had an excellent one! and differences in performance were not subtle.
Doubt Schemphlug is an issue since it was adjusted and differences are for the center of my screen and not sides. I will take screenshot showing differences at center between 10F/10L Lenses. Differences "might" be because each model have a certain focal plane distance sweet spot and I had my 10L on it. Both have same throw between... Anyways I am very happy with my old HD10L (clear 1080p desktop text) and the 10F are sitting in the corner of my kitchen :D. (To be fair, the 10F had better corner focus, but since center is much more important(knowing eye center acuity, their kitchen place is justified!)

Curt,

Thanks, I ll do just that. By the way, I think my PJ is really cursed now since yesterday after finishing all convergence and color calibration and placing it on the ceiling, 1 hour later while watching movies, I hear a little noise and blue doesn't focus anymore :( :(. This is a brief history of my 1 year struggle with the PJ:

1-Glycol Leak. Repaired then
4-Brocken red tube. Swapped then
2-Green HV Arcing. Repaired then
3-HVPS failure, HDM failure(Twice!). Repaired then
5-Bright Green window on the tube. Repaired by swapping the VIM then
6-Bad blue convergence. Convergence Board swapped.
7-Gobal blue defocus. Repair under way.................

I think the year didn't end yet... CRT is not for the faint heart :D

This is a brief history of my 1 year struggle with the PJ:
1-Glycol Leak. Repaired then
4-Brocken red tube. Swapped then
2-Green HV Arcing. Repaired then
3-HVPS failure, HDM failure(Twice!). Repaired then
5-Bright Green window on the tube. Repaired by swapping the VIM then
6-Bad blue convergence. Convergence Board swapped.
7-Gobal blue defocus. Repair under way................. I am amazed you have the determination to stick with a machine like that? I love the Marquee's but i've never seen a machine with so many problems before:(

Wait, those are MP modded VNB's.
http://www.avsforum.com/avs-vb/attachment.php?attachmentid=131577&d=1233156940

Can you look closely at the RED VNB and see if it has a hole in the same place that the white G2 wires is conected on the Green and bleu. The red is conected into the "KEY" part of the Tube. Or take a close up of the red VNB at a nice straight on angle so we can get a look at all the pin placements.
the blue and green could also be LUG's.

it also looks like the Green VNB cage is grounded to the Ground wire from the VDM and covered with black electrical tape? why?
I would make sure the ground wire from the VDM is a straight line to the chassis and the Green braided cable goes to the rear heat sink when its in the closed posistion.

Also connect the black flat ground wire back onto the raised ground connector on the VNB like the green and blues.

it also looks like the VDM and SWA board have been cap upgraded, I wonder why the CVA wasn't done? that one shows the most improvement in performance on a marquee.

I was going to say swap out the VNB's but you cant do that if the red is different, you said you have another marquee? If those VNB's are like the reds
with no hole in it for the G2 line then swap one of those out. the OVER-I circuit on the VNB might be triping the blanking circuit possibly. I forgot if it just shuts of HV or brings the +/-85 line to full 85 to blank out the tube.
I bet its the red VNB though since you said the G?B light up when the HV lead for the red is pulled out.

Curt could help more than I though....

Athanasios

Athanasios, do you replace the caps on the VDM, SWA, and CVA with like value and voltage caps, or do you use caps with a higher voltage? I have a high hour (13K), retubed Marquee 8000 that I'm whipping into shape. The previous owner spent some cash putting in brand new tubes, but didn't bother to refurbish the boards!

Thanks!

I have a high hour (13K), retubed Marquee 8000 that I'm whipping into shape. The previous owner spent some cash putting in brand new tubes, but didn't bother to refurbish the boards!
Thanks! IMO it's really not worth putting that kind of time and money into an 8000. find your self an 8110 or 8500 and swap those tubes right over. Then the board work really pay's off

When it comes to swapping caps you should try and stay close to the original voltage value, as for the capacitance value you can increase somewhat depending on where in the circuit it is. Increasing the voltage rating does nothing to prolong its life providing the cap was spec'd correctly in the first place. Actually using a voltage rating too high won't allow tha cap to work like it should as the dielectric doesn't form properly when powered up.

When it comes to swapping caps you should try and stay close to the original voltage value, as for the capacitance value you can increase somewhat depending on where in the circuit it is. Increasing the voltage rating does nothing to prolong its life providing the cap was spec'd correctly in the first place. Actually using a voltage rating too high won't allow tha cap to work like it should as the dielectric doesn't form properly when powered up.

Really I always thought it was afe to go up in voltage as this is what many of Mike's mods do. Also i have not seen any adverse affects in keeping the same value uf and going up tot he next voltage. Higher voltage caps mostly have higher ripple current ratings and sometime lower esr's.

On the CVA the main caps on older boards were of larger voltage ratings and those CVA's had less failures while the newer boards with a lower voltage rating cap fail more offten.. Right Dragnm.. We have both seen this
on the Marquee. And from my scoping the CVA board the noise level on the
convergence circuit has gone down some compared to a stock board.


Can you Explain why?

Athanasios

I didn't say it wasn't safe, I said it's not good to be running the cap at a voltage too low below its rated working voltage. In the case of the typical electrolytic the dielectric is properly formed only when the voltage applied is within a certain range of its operating voltage, too high a voltage rating with too low applied voltage and it won't function as it should. Yes higher voltage caps have some better specs but if you can't run the voltage where it should be then chances are its not going to meet those specs.

as I said "Increasing the voltage rating does nothing to prolong its life "providing the cap was spec'd correctly in the first place" ".

I didn't say it wasn't safe, I said it's not good to be running the cap at a voltage too low below its rated working voltage. In the case of the typical electrolytic the dielectric is properly formed only when the voltage applied is within a certain range of its operating voltage, too high a voltage rating with too low applied voltage and it won't function as it should. Yes higher voltage caps have some better specs but if you can't run the voltage where it should be then chances are its not going to meet those specs.
This might be true in a very extreme exmple, like a 200 volta cap in a 10 volt circuit. However generally speaking it's contrary to everything i've seen in a Marquee, both in failure and performance. the VNB's are a great example, 85V rail with a 100V rated cap , sounds perfect right? Actually it's a proven disaster for the longevity and performance of the circuit. The cap gets overdriven which then causes overheating and and even more leakge in a downward spiral. The correct proven cap size for this circiuit BTW is the Same capacitance and double the voltage = 22Uf 160V cap and that's also coincidentaly what VDC uses in a modern Marquee.
another piecee of evidenece that's not conclusive but is anecodotal is the circuit board itself. The graphics on the boards almost always show a much larger foot-print for the caps than what is actually installed. Athan mentioned the CVA but it's found all over. This seems to indicate that the circiut was originally designed a lot more robust and then downgraded to save money. Good caps are expensive, you can spend $50. on a single machine for just the Aluminum electrolytics.

as I said "Increasing the voltage rating does nothing to prolong its life "providing the cap was spec'd correctly in the first place" ". well that's the million dollar question isn't it? There's a lot more to it than simply voltage. You have to consider the leakge rate, or rated ripple current at the frequency the circuit will be operating at. I think it's safe to say that in a traditional electrohome/Christy digital Marquee every single capacitor was underated for the High definition/ high frequency scan rates people are using today. I've been testing this for months now and the results sure seem to support that as well.
BTW, if you guys really want to discuss this it deserves it's own thread, not tacked on to the end of the Cow's tale of Marquee woe :D

I'm not questioning what VDC choose to use. So I guess because it's contrary to what you've seen in the marquee then what I've written must be BS, believe what you will. If you don't understand electronics or designing same then I can understand where you're coming from.

Dragnm, here walt is correct . I always value what he say's and am glad he spoke up.

I found this info:

http://www2.electronicproducts.com/Capacitors_in_high-voltage_applications-article-itw-may2006-html.aspx

Electrolytics
Like batteries, electrolytic capacitors work by chemical action and tend to deteriorate with time. The small leakage current exhibited by electrolytic capacitors is a necessary nuisance in maintaining the oxide film by continuing the forming process that was initially done during manufacture.

Operating an electrolytic capacitor at only a small fraction of its maximum working voltage can cause deterioration of the dielectric film, resulting in loss of capacitance or even total failure. For instance, aluminum electrolytics have longer operational life when operated at 70% to 80% of their rated voltage.

Electrolytic capacitors represent somewhat of a conundrum. When first used in a circuit, they have a voltage safety margin allowing the capacitors to handle the occasional voltage surge that occurs in almost every application.

Unfortunately, if operated below their rated voltage, the capacitors will reform to the voltage at which they are being used, and any voltage surge can result in circuit failure. At the same time, if the capacitors are used at full rated voltage, the leakage current will result in I2R heating losses that will begin to degrade the interface between the electrolyte and the metal resulting in eventual capacitor failure. The basic rule of thumb for electrolytic capacitors is that for every 10°C increase in core temperature the capacitor life is cut in half.

So Electrolytic caps last longer when run at 70-80% of their rated Voltage.

Good to know.. A little too late. I guess we have to hope the circuits don't have a voltage Spike in the circuits as they now conformed to the new voltage.

I did not go up too high in voltage rating for most caps I used.

On the VNB the original cap must have been under speced and the new rated cap should have been used from the get go. That circuit must have many spikes to necessitate the use of the higher voltage.

Athanasios

there's no need to get offended Walter, I was strictly speaking of the Marquee which is the most popular PJ in North american. We are on the CRT forum right?:)
I'm sure there are circuits operating at very low voltages and/or delicate signals where cap size and power rating are critical. The Marquee isn't one of those cases. we're talking push/pull amplifiers here and the brute force required to drive a coil at very high frequency's. the cleaner you can do that the more you bring out the inherenty qualities of CRT projection like super fast motion (retrace) capability to name just one.

Hi Athanasios,

Damn you must have searched high and low for that, but that's exactly what I was talking about. Maybe I should have just a done a search and posted the link and saved myself the bashing.

Yes we are on the CRT forum but sometimes I get the feeling that if your initials aren't MP or tse(Scott) whom are both great guys and knowledgable then what you offer is always questioned with a gain of salt. Oh well I'll live to speak another day on another topic no big deal draganm no offence taken.

Dragnm, here walt is correct . I always value what he say's and am glad he spoke up.When run at 70-80% of their rated Voltage.Good to know.. A little too late. I guess we have to hope the circuits don't have a voltage Spike in the circuits as they now conformed to the new voltage.
Athanasios
that's a completely simplistic statement for them to make and if you notice the article relates to high voltage power supply's which typically have a constant power output like the HVPS on the marquee = always at 34.9KV. It completely ignores what happens to a capacitor as temperature and frequency start to increase, they don't even mention it. Yes, applying voltage heals defects in the electrolytic. That doesn't help though when you have a cap rated at only 80% of it's MAX power handling that's now running at 100C and the ripple current starts to climb. The temp of the cap rises and it starts to break down. Here's a white paper that talks about the direct link between underating a cap and cap life.
http://www.cde.com/tech/multipliers.pdf
The voltage multiplier f2 arises from the lowered stress on the dielectric when the applied DC volt-age Va is reduced. In electrolytic capacitors, applying DC voltage actually drives a beneficial, on-going electrochemical reaction that heals defects in the anode dielectric. However, at higher stress levels such as when the temperature is near TM ,the additional leakage current from operating near the maximum voltage rating Vr may cause enough electrochemical degradation and hydrogen gas evolution as to reduce the life of the capacitor. Therefore a reduction in the applied DC voltage may extend the life of the capacitor, especially at elevated temperatures in capacitors that are tightly sealed. The effect of voltage derating on life has been modeled with linear fit and with power laws of the voltage ratio x=Va/Vr with exponents from 0 (no effect) to 6. See Figure 1.
So, what they're saying is that is you are operating a cap close to it's rated voltage potential and high temperatures combined with high frequency's (such as 1080P 72HZ) , your better off using a cap with a higher voltage rating as that will have the most benefit to the life of the cap and it's ESR specs. They're also talking about modern caps, tightly sealed and using the most modern electrolytic compounds. Not some paper capacitor from a 1950's radio that needs to be re-charged every time you listen to Ed Sullivan show.
Stick your hand inside your Marquee next time you get done watching 4 hours of a movie at higher scan rates. The factory caps, rated at the first articles recomended 70 or 80% of circuit voltage, are cooking. The Aluminum heat sinks are too hot to even touch. How can that possibly be extending the life of the caps? :confused:

On the VNB the original cap must have been under speced and the new rated cap should have been used from the get go. That circuit must have many spikes to necessitate the use of the higher voltage.
Athanasios
I'm pretty sure there are no spikes on the 85 Volt rail. See my post above for an explanation of why those caps go bad

Both posts Dragnm make sense also.... I am sooo confused !!!! ;)

But from my experience so far, the higher voltage caps are fine for now ... over time is something only time will tell.

Athanasios

I can agree with both sides of this discussion.

First, the problem with the 22uf 100v caps on the marquee neck board was they were low temp (85c). Low temps should never be used on higher voltage rails. They're fine for 5, 12, 24 volt switching rails, but should never be used in higher voltage rails. That's why the later version Christie neck boards had the black 22uf caps. They were 105c temps. the other problem with that cap was the voltage rating (100v). The 20% rule does apply here, but we're dealing with a switching supply, and that should move the 20% rule further out. The caps are DC rated, but with switching supplies there's a high frequency element there that would not be found with a passive 50/60hz supply. That HF element is why we should be using higher voltage caps on higher voltage DC switching rails. Not sure why, but it's seems to be the only way to both keep the cap from premature failure and at the same time, provide the best performance. A 105c cap is the same as a HF cap. So that's what makes them always better for these rails. 85c caps should only be used in lower voltage rails. Therefore, the temperature rating of the cap has more to do with voltage and the type of supply than the environment it will be used in.

For instance. I used to use 47uf or 100uf 105c caps on the neck boards of my mods. The voltage ratings of those caps were 160vdc. I've since went back to the original cap value for the neck boards, but has increased the voltage rating to 250vdc 105c. The 47uf to 100uf worked much like the 22uf when sweeped, with the 22uf doing even better lowering the HF component. The 47uf to 100uf did best with ripple, but the ripple was not a problem, it's the HF component that needed the attention - and the 22uf was best there. however and somehow, it has to be a higher voltage cap.

On other areas of the projector, say like focus, stig and vertical. the same applies even though they are lower voltage rails. Things seems to somehow do better with higher voltage caps there. And I've noticed the same on some Sony and Barco boards.

This may go against the rules, but that's what I found to work out better for me. And that's what got my attention to the work dragenm was doing to the boards. Not sure how he arrived to the same conclusion that I did, but that's why I asked him to take on doing the other boards in the Marquee.

Draganm, you have no idea what you're even talking about or maybe I should say you are misunderstanding what is being done or what is going on in the marquee and what that paper is saying. But hey you're the expert on this by the sounds of it. Spread the good word.

Draganm, you have no idea what you're even talking about
Walter it's unfortunate that you feel the need to attack me personally instead of adding something meaningful to the discussion. I based the work i've done on the Marquee on many years of work done before by MP, Jaehong Lee, and other people very familiar with the Marquee. The results I've found to be completely in line with previous work done. Matching a cap to a rail in the Marquee based strictly on 20% headroom over the voltage rating of a circuit in the Marquee handicaps the machines full perfromance potential.
I'm done flogging this horse though, MP was kind enough to touch on the key points, and soon people will get the chance to test the premise in their Home theastres. I'll let the results speak for themselves.

Hi Draganm,

It wasn't meant to attack you, it was to say that because you have done some experimenting on the marquee you think you know how the theory works which makes it okay.
So what I take from that is because you've replaced a few electronic components here and there that that means you know electronics and are expert enough to comment on these theories. I don't claim to be an expert in this but I do have a background in electronics and it has been about 30 years since I graduated.

Sincere question; Do you have an education in electronics? If so then I appologize for doubting you.

Sorry guys, don't want to go off topic :D but my blue focus problem isn't sovled yet.
The problem is that it comes and go alone without me touching anything. Sometimes it works, sometimes not. I swapped the focus vertical board and no improvments.

Tkx for any help....

Which Board did you swap? the focus board or the Vertical deflection Module?

Try to clean the chips on the CLM or swap out a CLM. the CLM generates the focus waveforms and so does the VDM or CVA not sure. But if you look at the Blue Grid
Which lines are out of focus? the vertical or the horizontal, also are the edges out or the center?

also did you try swapping the focus coil connectors on the FCM, put the red on the blue and the blue on the red and see if the red goes out of focus.


Athanasios

No, do the simple stuff first. :)

Swap the focus leads going to the tubes, so that the green focus control adjusts the blue tube and vice versa. It's a bit tough to tune in, as the tubes shut down to only adjust the color that the focus is set to, but since your focus seems to jump around, get it close on each tube, then run the set to see if the same color tube changes focus or not. If it's stil the blue tube jumping, then I'd suspect a bad focus yoke. if the green changes, then swap the CLM.

No, do the simple stuff first. :)

Swap the focus leads going to the tubes, so that the green focus control adjusts the blue tube and vice versa. It's a bit tough to tune in, as the tubes shut down to only adjust the color that the focus is set to, but since your focus seems to jump around, get it close on each tube, then run the set to see if the same color tube changes focus or not. If it's stil the blue tube jumping, then I'd suspect a bad focus yoke. if the green changes, then swap the CLM.

Yeah Curt said it better than I did ;) I meant the same thing in a longer round about way.

Athanasios

Tkx guys,

The problem was fixed by tapping gently on the back of the tube. So something might be loose. it comes back again in a while and its time for another gentle tap....

I swapped the 2 pole astigmation-Flare & Focus yokes with the old one I had.
Now blue is ok except for a long 30sec period for focus to settle(Something not found on my R/G Tubes) on PJ Startup. My PJ is gowing up the ceiling tonight! :)

I swapped the 2 pole astigmation-Flare & Focus yokes with the old one I had.
Now blue is ok except for a long 30sec period for focus to settle(Something not found on my R/G Tubes) on PJ Startup. My PJ is gowing up the ceiling tonight! :)

That is not right, I think you have a short in the blue tube. You might want to
keep tapping the tube while its running to knock out and burn up any "crud" that got into the guns. It probably happened during shipping.

OR it could be the one channel for focus. DID you swap the focus connectors around from another color tube to see if the bad focus follows it?


Athanasios