[RobertV]

Any suggestions on wire to use for mini-RCA RGB wires on my Ehome?

I have a MP-1 moded Radeon 9500 with Canare wire to the PJ and am in the process of upgrading the rest of the video chain in the PJ. Thought that it might make sense to upgrade the OEM coax while I'm at it.

What have you folks used?

TIA

 

[mp20748]

Robert,

I plan to offer improved cables for the complete mod, once we're done with the testing process.


You are tester number seven. I only have one more person after you- then it'll be time to go forward. So far it's looking very good

 

[RobertV]

Always great to hear from you and what your are working on!!!

 

[bblue]

Robert, the actual cable upgrade is with Commscope 735 01S mini coax. It's a bear removing the old male mini-rca connectors and prepping them for the new cable, so if Mike can offer you new connectors and the cable pre-made as part of the kit, that would be the way to go. I did it the hard way.


--Bill

 

[sly]

I think the cable they used is fine but the mini RCA is not a 75ohm connector and it does cause a reflection.

If you look at it with a TDR there is a big bump where the mini RCA is.

The mini RCA is a very very cheap part thats all.


I would think something like a SMB or a SMA would be a good replacement on both the VIM and the neck PCB


I think if you cut off two of the ground pins it will fit in the PCB. And the SMA or SMB parts are very easy to get.

they just cost a little thats all.

 

[mr.beam]

Mike,

I'm interested in your new cable! MP-1 mod is running in my PC, and the picture is (was) outstanding, because pj is now out of work! I tweaked it to death..... but it needs a cable upgrade inside too, first I have to change the H-out transistor, if only this is worse.......then new cabel, and a silent fan mod too! New coupling caps....???? What else can we do to get THE pic....

Daniel


The beer is cold!

 

[bblue]

Sly, is that a reflection that can actually be seen on the display, or just when scoped? I was wondering about the impedance of those things when rewiring.


Do the SMB or SMA types come as right angle units? I haven't looked at those for a very long time.


--Bill

 

[mp20748]

Guys,

the impedance of that connector is a non issue. It could only be an issue if the distance of the cable was in excess of over 30". In other words, the cable distance is too short for ringing/ghosting to become an issue.


As I've said before, my reason for changing out the cables is to provide a better GROUND connection between the VIM and the neck boards. There's absolutely no ringing, ghosting or banding introduced in the video chain on the necks boards of the projector from the original cables.


SMB's or SMA's are a bit overkill for this application. They are better suited for good impedance matching and isolation in high frequency RF industrial applications. And maybe that's why I can't recall seeing them in any of the other commercial grade CRT projectors.

 

[sly]

I see it on a scope. And yes they come in right angle.

30" well I would have to disagree on that one.


We have seen on some system boards here just having the VGA connector (which is not 75 ohm ether) just 2 or 3 inches on the PCB from the driver(ATI chip in this case)

cause reflections that could be seen on a monitor.


Call me anal but I like to see no bumps in the impedance of a video path. But I am used to working with very hi-res displays.


Is is interesting that there seems to be a ground problem.

But not surprising with all the different paths ground can take.


I would like to see the neck board tossed in the trash too

It is a very old very smiler to a neck we used 28 years ago

with the same transistors and all the same failures.



I have been toying with the idea of making a new neck and getting rid of the VIM too.

I was thinking of using the Hitachi FA4111B

I think I would have to use 2 the CRT seem to be fed differentially to G1 and cathode if I read this right. I need to look at it with a scope..

But I have had a heck of a time getting specs on the FA4111B. Which is strange it seems to be used all over the place.. Anyway just a thought.

 

[jcmccorm]

Sly, the Marquees do indeed drive both the cathode and G1 differentially. It's kind of cool because by driving both they can get the same beam current with only half the signal swing (and therefore better bandwidth).


Cary

 

[mp20748]

Quote:

Originally posted by sly I see it on a scope. And yes they come in right angle. 30" well I would have to disagree on that one. We have seen on some system boards here just having the VGA connector (which is not 75 ohm ether) just 2 or 3 inches on the PCB from the driver(ATI chip in this case) cause reflections that could be seen on a monitor. Call me anal but I like to see no bumps in the impedance of a video path. But I am used to working with very hi-res displays. Is is interesting that there seems to be a ground problem. But not surprising with all the different paths ground can take. I would like to see the neck board tossed in the trash too It is a very old very smiler to a neck we used 28 years ago with the same transistors and all the same failures. I have been toying with the idea of making a new neck and getting rid of the VIM too. I was thinking of using the Hitachi FA4111B I think I would have to use 2 the CRT seem to be fed differentially to G1 and cathode if I read this right. I need to look at it with a scope.. But I have had a heck of a time getting specs on the FA4111B. Which is strange it seems to be used all over the place.. Anyway just a thought.

Sly,

I think you may have a broken projector. Because if it's a 8000, it could have any of the early quirks that were solved on the later 8500/9500's. There were several revision to the neck boards from the 8000 series, and there was even a transistor placed on some boards that a tech bulletin indicated that it should be removed, because it was accidentally populated on the board.


As I've stated before, we're not redesigning the Marquee on this thread. We're simply looking at "maintenance" and "upgrades".


I know you're sort of new to the Marquee, so I give you a little background info:


It is the only commercial grade CRT projector model that has been in production for over ten years. It is the most popular CRT projector to get rebadged and sold by others (Vidikron, Magrigal, Tauu, Crystal View, Reference Imaging, Etc.). Now with all of those companies choosing this model for their high end sales, to include it being the most popular CRT projector for high end computer presentation systems. We now find out that there's an un-viewable ringing in the video chain


The neck boards on the later version Marquees were ROCK Stable, and rarely failed. The ones that did fail were most likely caused by overheating of the board from being on in 24/7 operations. Other than that, the video chain in the projector has been praised by a many engineer for its basic and straight forward design. Plus the neck boards seem to have gotten the highest praise, because it has suffered the less changes over the ten year production life of this projector. The Marquee is still in production, and they're still using the same neck boards and VIM's, fact is, they're still using the 02 VIM from the 1995 vintage. It has won many consumer trade show awards, and appears to have been the only CRT projector at the last CEDIA show.


Not sure what you're seeing with your scope, but I have a perfectly clean image on my 9500LC, with absolutely no ringing, banding or any artifact from improper impedance, and I still have the mini RCA's in the projector. If in fact I was able to see anything on scope of in the image - the mini RCA would have been gone. I've been working on cleaning up the video chain in this projector for over two years. I may have missed something, but it wasn't the mini RCA's.


The only thing I've noticed is the hash noise on the rails, but that's in all electronic gear, but it's only a problem for analog video. And it's in everyone of our analog projectors... But I've been on its butt

 

[srp68]

Quote:

Originally posted by RobertV Any suggestions on wire to use for mini-RCA RGB wires on my Ehome? I have a MP-1 moded Radeon 9500 with Canare wire to the PJ and am in the process of upgrading the rest of the video chain in the PJ. Thought that it might make sense to upgrade the OEM coax while I'm at it. What have you folks used? TIA

RobertV, just curious. How long is your Canare RGBHV cable from the HTPC to your Marquee?

 

[Jay Wilson]

I have been looking for the cable and fittings as well instead of having to reuse what is there...as bblue did. I believe in the maintenance thread a link to the fittings is there, but I too would be curious about a better cable.


I have also thought about hard wiring (soldering) one end to wither the neckboards (preferably) or the VIM. Any thoughts on that?

 

[sly]

"As I've stated before, we're not redesigning the Marquee on this thread."

Heh which thread do you think this is

Like I said I am anal and I always see stuff no one else sees.

I woul drive the mounter vendors crazy they show us a new CRT

I pointed out defects in the shadow mask the instant I enter the room.


I have used Ehome sense the ECP came out. in fact I helped them fix one of there problems with their sync board.

They were nice to work with and gave me a free extension PCB so I could work on the cards.

I think the change from the ecp to the Marquee can not be under stated. But on the flip side the new 9500lc's we got blew up all of them they said it was a known problem but we had have down time each time one poped.

And the the real disappointment was when we ordered some 8500 to do a video wall I think it was six. Anyways each projector had different color phosphor and different gamma curves

almost impossible to match..

And the 8000 's

like the one I have at home now is sharper then the new 9500lc we got. So Ehome has there good days and there bad days but who does not. The resin I was thinking of a new neck was because I think the bandwidth can be improved a lot.

I run at 1920x1080p all the time

also I would not use any other PJ

The barco 's don't look bad but the setup seems so hard compared to a ehome

and the Sony is a joke after playing with there set up for a bit I want to rip the PJ down and take a hammer ti it?

I have never tried the NEC so I can't say.

but I do think the Ehome is a great PJ it is just that I think it could be better. I do not care how good it I the kind of person that will find a way to make it better. I never learned that saying if it ant broke don't' fix it


It is just that the design is old it was top notch at the time

but things improve over time. And there is stuff that was not around back then. If there were to make a new CRT PJ today it would be a very different system just look at monitors at that time they had just about all the same stuff, now a new one a two small PCB,s and way out performs the old monitors. Its too bad the digitals killed the CRT [email protected] I think if there was a new design built today it would be something..


it seems the Ehome has only2 problems the HVPS and neck fails the HVPS seems to be the worst..

and the heater problem but that is easily fixed so I do not count that. It would probably be wise for the time to be spent on making a new HVPS replacement.

but that seem a bit harder . I am a video guy not a switching power-supply guy.. and the fly-back vender's are so hard to work with all they want to do is make a custom one and will not give specs on something they make all ready.

so it is hard for a small run.

I will dread the day when I have to go digital. Every time I look at a panel even the 1920x1200 LCD's all I see is that every pixel is a different color and shade. as well as I want to converge it the RGB stripes seems so bad.


like I said I was toying with with the thought.

 

[Curt Palme]

Wow, 13 posts so far, 155 reads, and no one has suggested a 2 gauge cable upgrade yet with a big honkin' buss bar???





Curt

 

[RobertV]

I would like to make it much shorter, but I have physcial limitations.

Ahhhhhh...Yummy.....2 Gauge.....more power!!!!!

REV