CurtPalme.com Home Theater Forum

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Frenchman · Joined: 01 Jun 2009 Posts: 3

Hello Good people!

I have been following all the posts on that subject with great attention. As I wrote earlier in this forum I have a 1292 with only 1300 hours, the image is just fantastic, have been able to display 1080p through the Moome card with great results, the 1292 is very, very sharp and the colours are nothing but wonderful. I am not worried about the lower light output as my screen is only 2m wide. Of course, like all the other owners of a 1292 I do have some streaking problems. I have to say I am not very literate with the CRT technology yet so please apologize my ignorance! I did voted yes and will definitely modify the boards, the tests look very promising this far!

I noticed that the streaking goes worst when playing at high frequency rates and when the room temperature is higher. I got my 1292 in February this year, barely noticed the streaking on DVDs, now playing Blue ray discs in the hot summer, the streaking is pretty bad! Crying or Very sad

Actually, how does the streaking builds up? Does anyone have an "easy to understand" answer? Very Happy

I am in the process of building a nice floor mounted hushbox with 2 separated inner walls and isolation and was thinking maybe adding some ventilation to cool the baby even more. My 1292 has Vantec low noise fans but when I compared with the original ones, I think they do not ventilate as much, maybe I would need to compensate the airflow with two 120mm extra fans. I've seen a very interesting fan design on this forum, very inspiring indeed especially relocating the neck board fans to the side!

Any help is very much appreciated!

Laurent from distant France

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

It’s alive! The home brew amplifier is limping along however the output is crappy (technical term). The data shown on the scope is a single line (sweep) of data (line 122) of a 1080i RGBHV signal. The displayed data is a black background with the text “HELIOS” centered on line 128. The scope is connected directly to the output of the amplifier. Looking at IMG-0151 you can see the blanking pulse (if you can call it that) followed by video signal. Image IMG-0152 is a close up of the video signal; two problmes, the edges are slow(response) and an overshoot at the top and bottom of the signal; the signal should be almost flat at the bottom.

Not great but a start!

azzkicker · Joined: 20 Jan 2009 Posts: 33 Location: Germany

hi

i wait for this streaking mod soo long
but i think so with asubert

iam here in germany and sent my parts oversee takes a long time, and i have a long time no homecinema, this is the dead for me

the best way for me is sending the parts to me, i payed bevor and i need ecaktly instructions to put the mod an my neckboard

send me an pm i cant wait

best gereards

Frenchman · Joined: 01 Jun 2009 Posts: 3

Hi there,

I live in France and I have no problem sending the boards, the fix is worth a few weeks wait! Honestly, once this issue is solved and the 1292 carefully placed on a vented hushbox with insulated double walls, the 1292 could well be one of the best CRT bargain around! Waiting for more good news.

Very Happy

EdoFede · Joined: 20 Apr 2009 Posts: 21 Location: Milano, Italy

Hello to all.

I'm interested for this modification too.

RogueChili, do you think that is possible to do a "DIY" version of the mod, once the problem of the waveform is solved?

Great work! Cool

Bye,
Edoardo.

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

azzkicker · Joined: 20 Jan 2009 Posts: 33 Location: Germany

yyeeahhh

i cant still wait for this great mod

regeards

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

EdoFede · Joined: 20 Apr 2009 Posts: 21 Location: Milano, Italy

WOW! Very very good Cool

azzkicker · Joined: 20 Jan 2009 Posts: 33 Location: Germany

hi

in a few days i have the kit Mr. Green

then i bring the mod on my neckboards, and hope ich dont see the f*cking streaking

regards

Frode · Joined: 13 Sep 2009 Posts: 1 Location: Las Vegas, NV

Just joined the forum and will definitely buy the modification.

It's been too long since I got my degree in electrical engineering to follow all the details, but it all sounds reasonable so far. I've put about 3,000 hours on my 1292 since I got it and had actually started thinking about getting another projector due to the streaking, but now I will wait and see.

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

It's a shame that this topic died Embarassed

I'm up and running again after moving home, the green neck board also gets dark Sad

I'll have a look at the fans because I think the problem is heat because it happens within an hour.
When my 1292 is off for 10 minutes the green tube works again but it gets dark soon then.
My blue neck board has the same problem, this was the first neck board I tried because of the short cables on it.
I want to move the rear fans of the neck boards to the sides to get the pcb's cooled better.
Maybe it has to do with the missing fans on the back corners but I doubt that because my standard neck board don't have this problem.

André

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Hi speedy, good to hear from you! I thought something happened during you move when I didn’t get replies to the PM’s I sent you.

The thread didn’t die; we are all waiting for you! Hope you can bear the pressure!

Regarding the problem you’re having, it is not clear to me how the modification is causing it and will need your help to understand it. We can continue troubleshooting via PM.

What I would like you to do, if you haven’t already, is disable the ABL circuit and see if that solves the problem. Let me know your results

As far as the missing corner fans, you should replace them as soon as possible. I have done extensive research on temperature control and can say with authority that the boards in that area run extremely hot.

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

I've never seen an abl jumper on a 1292, where can I find it or does it have a different name?

André

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Remove the jumper from pc board shown in IMG_0568.jpg and install it to pc board shown in IMG_0570.jpg. After you move the jumper you will have to adjust the bias levels for RG and B. Remember to record your original bias values befor making any changes.

I recommend the following adjustment procedure as a starting point:

1) Select the input of choice then enter the service mode
2) Select <BIAS>
3) Select Cut off <B> and <G> ( only red enabled )
4) Select ADJ <R> ( enable red adjustment )
5) Select STATUS <OFF> ( eliminate interference from status text )
6) using <<> and <>> keys adjust the bias level so you can just see the diagonal red squares. There should not be any light, other then from the squares, visible on the screen.
7) Select Cut off <R> ( red disabled )
8) Repeat for G and B
9) Select <MEMORY> to save the adjusted bias values to memory

Notes:

Turn off room lighting during this procedure ( you should not be able to see any ambient room light on the screen- screen should look black ).
Be sure only one tube at a time is enabled during the adjustment procedure.

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

Thanks, I'll work on it tonight Wink

André

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

My 1292 has showed a movie, including setting the bias it did run 2 hours without failing neck boards Thumbs Up

I think I can place the blue neck board too if it stays like this Smile

The streaking is invisible already Wink

André

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Yes, if you eliminate the streaking on any one of the tubes it becomes difficult to see the streak because it is no longer bright white and for the most part disappears in the background, under most conditions. The streak will still appear under certain conditions however and all three mod boards must be installed for the mod to work properly. Another issue is the time delay introduced to the video path by the mod board puts the signal out of phase with the other two signals. Theoretically this could cause a smearing effect.

What troubles me now is why the ABL circuit is failing. The mod does increase the video bandwidth slightly and knowing that a good deal of time was spent analyzing the ABL circuit. The conclusion was that there were no unwanted transient effects during the calculation of the beam cutoff current. The fact that disabling the ABL appears to solve the problem suggests there is a slight effect.

The EBRG board is where the ABL current is processed and it is possible that significant overheating of the boards is causing this problem by moving the ABL detection reference point slightly. The EBRG board is located in that area where you said the fans are missing.

I recommend you replace both fans before moving forward. Those fans force cool air over the EBRG board and into the neck board fans. Without them installed both the EBRG and the neck boards are going to get very hot and possibly fail at some point.

A good course of action would be to install the fans, complete the mod installation and verify it’s working properly with the ABL disabled. The next step is to enable the ABL circuit and see if the problem persists with the fans installed.

donaldk · Joined: 17 Jun 2008 Posts: 308

OT Rogue, how many tube do you have in stock, those CRTs only last 100 hours, fortunately twisting a new one in only takes two minutes a piece...