CurtPalme.com Home Theater Forum

[stridsvognen]

Now i tried to see what happened when turning U106 off. But it looks like i just got another problem.

[mp20748]

Keep in mind that the VIM is only one source of the noise keeping into the image.

There are several sources of the various noises that get into the video chain, and that's why I've used so many ferrite beads and inductors. Other than the rails, which most think is THE source of the noise, it's really only one of the sources, with there being up to 6 other places where the noise can enter the video chain.

First understand that when these projectors were designed, it was before HD signals and they're target market was commercial presentation systems. Where noise was not a real concern considering the quality of the image material. But now and today, we are looking for noises. And that has a lot to do wit the quality of our source and image material. The better low end and black level performance put it right in our face.

The noise you have so far eliminated is the noise coming from U106, which is the OSD and Internal Generators. By disabling U106, you removed those two sources. But there still is quite a few more. For instance, the tube filament and the G2 lead puts noise on the neck boards. Not sure if you noticed, but in my neck board picture, the 10K resistor is removed and replaced with a large larger than 1/2 watt ferrite bead. And you also see in that same shot two more beads (1206) on that neck board. They are not just placed everywhere I could put one. I placed them in those spots after chasing down noise with my scope. One of those beads replace a different type of bead, but the other two were added.

Now that was the neck board, and I still have added several more inductors on that same neck board.

Now back to the VIM. It may have up to 25 inductors added (both coil and bead).

I had to filter or decouple "Blanking, sync, and all other lines that connect the actual video chain to the other circuits. Therefore both sweep and control pulses are decoupled.

The SD5401 work well bandwidth wise, but it does some really weird things to the image. I've always thought it had something to do with a switch that does not have a ground reference, that somehow allowed the control lines to be directly involved in its final signal result.

You're on the right path, and be mindful that I will be posting more later on how to decouple these noises using both inductors and caps, because you can only do but so much using caps alone. At least using my version of things. And I'll also post back the same blue tube shot to show what differences these changes can make.

The cleaner the noise floor, the better the overall low end performance..

[stridsvognen]

I hope that someone soon will make a 10" CRT native 16-9 tubes. Handling 1080P 96hz with no sweat.. made just for us..

[1031]

[stridsvognen]

[mp20748]

Without reading through all the threads, I'm sure I had mentioned that removing the INT-EXT also removed the blanking.

The Blanking is on INT-EXT. It is inserted into the video chain thru the "V-SEL" on the SD5401's.

On my setup, those outer lines are very barely seen, so there was no real reason for concern. I had also planned to look more into it once I get my test-bed fired back up, because I wanted to track down that entire Internal Generator and what it's putting into the video chain when it's not active.




I told someone I would post what I use on my neck board to replace the tant (C17):



Uploaded with ImageShack.us

[kabuby77]

[dvh99]

ok, i just soldered out u106 just to test and got rid of the resistors on the vim.

i don`t see any bright lines (not even barely) when looking into the tubeface so what`s up with that?

the pic immediately looks better again, never should have installed the fix cause that faint line never really bothered me.

[Tim in Phoenix]

[stridsvognen]

[stridsvognen]

[stridsvognen]

Anyone remember this one.?

I just found out where that noise come from.. Its from the controle board.. Not the VIM

[mp20748]

Just change all the tants on it. For the four near the multi-pin connector, use either 220uf or 470uf 25vdc.

[stridsvognen]

[mp20748]

You're having this noise after changing the caps?

[stridsvognen]

[mp20748]

Oh I see now. I was thinking it was the CLM from your New Marquee. Overlooked that it's in this thread.

I've only had one CLM that had a noise problem that was not solved with cap replacement. Not sure what I did with it, because I used another one in its place.

Was that problem only on the Blue CRT?

[stridsvognen]

[jbmeyer13]

This line is driving me crazy. Could the firmware volume on the CLM be causing this issue?

[stridsvognen]

Well i will guess not, i have a firmware 4.0, and a 5.0 and they have the same line..