Anyone for some Marquee Maintenance? - Page 3

Craig,
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.

Brad,
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

BLS,
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...

Brad,
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.

Ron,
I'm looking at the tech bulletin on this from the manufacturer

"VERTICAL SIZE MODIFICATION ON THE MARQUEE"

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.

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Brad,
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.

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

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

OK,
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.

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.