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Anyone for some Marquee Maintenance? - Page 3

post #61 of 614

I have a 98 or 99 (can't remember right now) EH 8500 Ultra. Will these or any other mods for the 8500 benifit me or have they been done already by the manufacturer since it is a newer model? Does it still need the anamorphic squeeze mod done to it?

post #62 of 614
Thread Starter 
you should be good. Unless you have an early version board in that ultra.
Read back over the thread and do the test for smearing.

You may need the anomorphic sqeeze if it has not already been done.
post #63 of 614
Can you describe what the anamorphic squeeze mod is. I have read a little bit about it on the forum, but I don't know the details. I can't get the search function to work here. It just hangs.

What does it improve and how much do you charge? I'm assuming because the PJ was designed for computer graphics and such, that we need this mod to improve the PQ of movies.

I have a 1995 Marquee 8000. I'm going to save this thread when your fiinished and do as much as I can myself when I have time.

What is your estimate of the average time it would take to do these mods? A full day, or more?

By the way, thank you for sharing your time and talent with us.

post #64 of 614
Thread Starter 

Originally posted by BLS
Can you describe what the anamorphic squeeze mod is. I have read a little bit about it on the forum, but I don't know the details. I can't get the search function to work here. It just hangs.

What does it improve and how much do you charge? I'm assuming because the PJ was designed for computer graphics and such, that we need this mod to improve the PQ of movies......


that mod is commonly known as "vertical squeeze mod" it decreases the vertical size for 16:9 operation. I think you're right that the circuit was probably designed more for computer presentation.

The mod requires the replacement of 3 resistors on the vertical board (R704, R804 and R904). These resistors are 30K ohm, they should be replaced with 56K ohm resistors, and it's best to use metal film resistors @ 1 to 5% tolerance. I use 1% 1/4 watt from Digikey.com:

Part# 56.2KXB
post #65 of 614
It sounds like the anamorphic mod and the other mods you have been sharing need the same skill level. Common sense, manual dexterity and a basic knowledge of electricity and safe work habits.

My screen size is 47.25" X 84"

With my 8000 on almost all aspect ratios the horizontal size is 100 (Maximum) in the size menu and I am able to adjust the vertical size to match the correct aspect ratio.

Do I assume correctly that I don't need the mod if I'm able to adjust the vertical to where it supposed to be?
post #66 of 614
Thread Starter 
so far, I'm sure the vertical mod is the only mod I've mentioned on this thread (I don't intend to get into mods). We've been discussing maintenance and upgrades. And most of the upgrades (chips) come from my notes, and we've not really got into much maintenance. The "vertical squeeze mod" was not commonly used back then, it was used only on one install that I could think of, and that was a 16:9 screen where the projector was used for a High def source. It seems to much needed for HT use though...
post #67 of 614
As long as they improve picture quality and reliability, you're the man! I'll call them whatever you want me to.

MP, it's all new territory to me. This is my first PJ. I have been dreaming about it for years. Iv'e got tons of patience. So if you only want to help with maintenance and upgrades, I'll be grateful for that. It will be more than I started with and that's why I'm here. Maybe someday I can offer something useful on the forum.

post #68 of 614
Thread Starter 
I hope I didn't make you feel out of place, because everyone that post has something useful to contribute on the forum, you're only asking questions. And if no one asked questions on the forum, there would be no purpose for the threads.

My goal is to stay focused on "upgrades" and "maintenance", and this thread is certainly open for discussion on mods and such, but MY intent is to stay the course, and I'll respect any comments between others on mods. And there are some very valid mods out there for the Marquee. It just that I'll not go into discussion on the ones that I know of.

For those who are into modding, I would highly recommend KBK. I've seen his workmanship, it's class "A" also because I'm against the average Joe with a Radio Shack soldering iron, attempting to transform one of these precious products into something it's not capable of doing. And it's been good hearing from some who would like to have their neck boards upgraded rather than try the procedure themselves. And the reports of the difference that's been made once the upgrades have been performed. keep in mind, I've not suggested something that the manufacturer did not do, I've suggested what the manufacturer did, but only without replacing the entire board.

I'm waiting to get back out into the shop, and when I do, we'll finish with both maintenance and upgrades, but I hope to post pictures on cleaning the dust from the various parts of the projector, and a few other things.
post #69 of 614

I'm against the average Joe with a Radio Shack soldering iron, attempting to transform one of these precious products into something it's not capable of doing. And it's been good hearing from some who would like to have their neck boards upgraded rather than try the procedure themselves.

I am one of the average Joe's who did the neckboard fixes himself. I needed to get rid of the horrible streaking cheaply as possible. I went 2 for 3. All I can say is unlike branches of the goverment, 'two out of three' is bad. One of the boards never worked properly after the fix, and I even had some help from someone with good soldering skills. Luckily, I was able to get a new board for free from the same place I got the PJ.

Anyway, I just wanted to backup what Mike said and be a voice of caution to any DIYers. The improvements are great, but so are the risks. If I had the $, would totally have someone else do this kind of stuff for me in the future.
post #70 of 614
I'm sure a lot of you folks would agree. There is nothing like the feeling of fixing something yourself. I'm 42 years old, so I have made a mistake here and there over the years. I agree it's risky, but during those years I have developed a sense of when I'm out of my league. Then I get to admire the skills of someone else.

I may start these procedures and find out i can't do it. I'm willing to try though. I've been into electronics one way or another most of my life.

Nathan, what do you think went wrong?

post #71 of 614
The board would work for a while, then start flickering, and then stop all together. I am not much of an expert, but it sounds like a heat issue to me, maybe a poor solder joint expanding? I came across the new board pretty soon after that so I didn't bother trying to fix it.

I am sure most of these things can be done with only moderate skill, but now I am a little hesitant. Especially since the thing is finally mounted, working, looking great, and I would rather watch movies than mess with it for a while.
post #72 of 614
Im all confused about most what your all talking about. My friend and I bought 2 EHome Marquee 8500's but the dept we bought them from at work says that they were going dim. we shined a flashlight into the tubes showing that the tube wear wasn't all that bad. We used that webpage as a guide that shows pics of various conditions of tube wear.

We would like to do everything your talking about here but have no clue what your even talking about. Power grid voltages, replacing all sorts of chips, getting electricuted. All sounds fun but we need someone to do this for us. Is there anyone qualified around Denver CO to do this?
post #73 of 614

Those Marquees sound like they are suffering the dreaded heater overvoltage problem. Down on the motherboard near the back of one of the outside CRT's you will see a small white 2 pin plug labelled P14 - using a multimeter set to DC voltage, check it. It should not exceed 6.45v - if it does, chances are high that the tubes are trash (but re-buildable through VDC). The LVPS needs to be upgraded to prevent this from happening again.
post #74 of 614
I have been saving the tips, fixes and so on for when I take mine down from the ceiling.

Can a do it yourselfer perform the LVPS upgrade?

Can you give any detail here?

post #75 of 614

I know that you want to avoid discussion of mods, but please clear one thing up. You described the vertical squeeze mod as:

"The mod requires the replacement of 3 resistors on the vertical board (R704, R804 and R904). These resistors are 30K ohm, they should be replaced with 56K ohm resistors."

On my EH 9501 LC, the person who sold the unit to me was adamant that a different resistor swap was needed. His assertion is that resistors 706, 806, and 906 should be changed to 490 ohms (leaving 704, 804, and 904 unchanged.) Is this correct?

post #76 of 614
Thread Starter 
I'm looking at the tech bulletin on this from the manufacturer


In this tech bulletin there is a reference to R706, R806, R906. And it states that 'IF' the existing resistor is 430ohm, replace with 470ohm, otherwise replace with 680ohm.

In other words, the resistance needs to increase and the existing resistors must first be removed. Some of the older boards used 430ohm resistors and they should be replaced with 470ohm resistors. Newer boards used 470ohm resistors and they are to be replaced with 680ohm resistors.

In this application the manufacturer recommended replacing the RAMP resistor. In the popular (R740,R804, R904) we're replacing the FEEDBACK resistor on the buffer amp.

the replacement of the RAMP resistor was the fix for PC boards:

50-2023-03P and 50-2023-03P these boards the tech sheet indicates that you replace R706, R806 and R906.

On PC board 50-002020-02P you replace R704, R804 and R904.

What I've found is that you can replace R704, R804 and R904 on all of the three boards. And the replacement of the RAMP resistors is not necessary. So the simplistic way is to replace R704, R804 and R904, mainly because the tech sheet has too many options to achieve the same thing.


I would recommend that you have the LVPS done by someone who has sucessfully done it more than once. Many are simply adjusting the pot to achieve the proper voltage, but are not replacing the pot, and if you make the adjustment without replacing the pot, it'll eventually flake out again. and if that happens the tubes are at risk. Also, it's important to make sure the repair is done right so that you don't accidently allow too much voltage on the tubes filaments, hoping to the voltage set to the right level.

My opinion - have it done by someone who's very familiar with doing it.
post #77 of 614
Thread Starter 
I have a digital camera on order. When it arrives we'll pick back up on this thread.

We're still going to cover the VIM, and from there we'll look at the rest of the projector.

Then, you'll get a chance to see why this basic chassis design has not been changed in the past ten years.

You'll need the following for the maintenance:

- Denatured alcohol (about $3.00 from home Depot).

- Standard tooth brush.

- Standard bed sheet.

- Vacuum cleaner
post #78 of 614
While I getting parts for my dead HVPS I took out my neck boards and to my surprise they seem to be the new type
my PJ it a 1995 8000

to I took a snap of it>>>

post #79 of 614
Next I took out the VIM
It had H1100 op-amps and a junk op-amp for red
I had cooked red a long time ago and just used what I had on hand.

here is the VIM ready for rework I had order the max4224

post #80 of 614
After removing the old chips off of the VIM

post #81 of 614
now the VIM with the New MAX4224 chips installed

post #82 of 614
Thread Starter 
Sly, you're on the ball here. Thanks for the pictures. I'm on my second camera and I can't get the pictures right
post #83 of 614
Thread Starter 
we'll put off the cleaning until I get my hand on a camera that I can make sense out of.

But until then, we'll move on to the rest of the set.

So far I've received very good reports from the chip upgrade on the neck boards, and some have already replaced the chips on the VIM, with very good results. The CLC449's were used in the later version Marquees, they replaced the CLC409 and H1100. Both of these chips had a roll off problem and could cause smearing and slight distortion in the image when used on certain resolutions. The H1100 may not show a problem, and may not be a problem from testing, so the replacement of the H1100 is an upgrade option.

Next we'll look at the VIM (I was hoping to have the camera for this). EArly version 8000's did not have the blue gamma circuit on the VIM. It was included on all of the later models. That circuit is a simple op amp, and maybe we can add it to the boards that does not have the circuit, I'm sure someone could make that little circuit and make it available, it'll be quite easy to install.

I'll throw in a mod.
The first thing that we'll do on this board (after the chip upgrade) is a Sync Mod. This is the removal of the sync circuit from the green input (sync on green), this is very important especially if using component to RGB conversion, because that could cause TRI- level sync on the BNC's (composite sync on all three BNC's). The problem that this could create is that you could have sync on all five BNC's. That's not a problem for the Red and Blue, but by having this signal on both the 'H' and 'V' BNC's to include the green BNC can confuse the auto sync detect circuit that automatically detects what type of sync that's being feed to the projector. The auto detect circuit looks for sync on the following: separate sync on 'H' and 'V' BNC's, composite sync on green BNC, composite sync on 'H' BNC. This circuit worked fine before component sync conversion came along possibly placing sync on all five BNC's.

This is a simple fix, remove R152 (it should be located about 1" from the blue relays) on the VIM module. By removing that resistor, you remove the sync circuit from the green BNC. There is presently no present modern application for sync on green (that I know of), especially for HT use.

Let's look at this and then we'll move on to a few other things on this board.
post #84 of 614
Mike, if you can develop a circuit, I'd be happy to design and etch circuit boards, and even write instructions, for a drop-in module. Heck, help me source the chips, and I'll even build ready-to-install boards. I have printed-circuit-board software and etching services available.

post #85 of 614
Mike does my PCB have the blue gamma circuit ??

if it does I could draw it up in eagle.
it appeared that all 3 pcbs were the same
I did not keep track of which was which..
I just pulled all three out I guess I should have marked them..
post #86 of 614
Sly, The gamma circuit would be on the VIM (Video input module) not on the neck boards.
post #87 of 614
Thread Starter 
The early version VIMs that did not have the blue gamma circuit, they had all three of the mini RCA plugs in line. The later version VIM (8000, 8110, 9000, 8500, 9500, etc) had the blue RCA plug slightly higher on the board and a little off to the right. The gamma IC on these boards is "U22".

Let's take Larry up on his offer to design and build the circuit for the early VIMs. But we'll need to see what the demand for them would be first.
post #88 of 614
OK the I see, that makes it easy there is a lot of room there.

I guessing the circuit has a fet in the feedback of a op-amp and uses the video voltage to control the fet.

I would think it would be easier to mod the op-amp that is there that way the video path will not have to be altered. and I do not think there is a need for a PCB or if one is made it will not have to be a pricey impedance controlled one.

so it looks like mine is the old one

I keep on kicking my self we had a VIM go bad on a new 9500 and they threw it out. I should have grabbed it..

This will be tricky it will have to run at full band-with with out any ringing. does any one know what the Gama value is??
Any one using a HTPC it seems a lot easier just too add that value to the LUT in the video card. I think most Video cards have the option to add gamma tables
post #89 of 614

I will purchase 3 of the gamma boards, either assembled or kit.

post #90 of 614
I just looked at the heater circuit on the LVPS
it is just using a lm117 voltage regulator

cool webpage to do the math

the circuit in the LVPS has a 120 ohm as R1
and a 1k pot 0-1K for R2
that gives us 1.25v - 11.67V

if you cut the trace and add a 470 ohm resistor in series with a 20 ohm pot
giving us 470 ohm - 490 ohm
we would get 6.1458V - 6.3542V
This also will have less power in the pot.
a value of 489.6 for R2 should give 6.35V

This seems very simple replace 1k pot with 20 ohm pot
one cut and add one 470 ohm resistor.

What do you think?

save them tubes
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