| Author |
Message |
secstate
Joined: 20 Mar 2006
Posts: 720
|
| Posted: Thu Apr 30, 2009 2:20 pm Post subject: Barco 1209s Red Tube Oddity Skewed and Bent Lines |
|
|
I have got a problem I haven't seen before. On my Runco 1100/Barco 1209s with all convergence and geometry set to midpoint and projecting the Barco grid pattern (either internal or synced with external signal) the horizontal lines on my red tube (even at center) have a strong curve up (like a smile) and the vertical lines are quite skewed (again even at center). The projector is level as is the screen and I have used my laser level to adjust the yokes to make them horizontally level. Neither blue nor green tube have the issue, they look normal. The problem is that I cannot get convergence spot on on Red and in several places (especially along the critical horizontal centerline) and I am really pushing convergence to get it right.
So far I have swapped the entire convergence tray, horizontal deflection card, vertical deflection card, and horizontal shift and focus card and none have changed the issue at all. At this point I am thinking it is either the magnetics on the tube or the tube itself? I have a spare tube but before I attempt to swap my other red tube I figured I would ask here to see if anybody else had any ideas. Thanks!
|
|
| Back to top |
|
 |
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Thu Apr 30, 2009 3:26 pm Post subject: |
|
|
ON certain BArcos (BG808s comes to mind) it does appear that some sets have the H lines skewed when the V lines are bang on and vice versa. Seems like Barco saw this as well, and most sets come in with the yokes slightly skewed so that some correction on skew is required in both the H and V planes. That part seems normal. The 'smile' distortion does not, but short of the SMPS, you've swapped everything out that could cause this IMHO.
That leaves the yoke boards with the H and V switches on it, or the red yoke. You've gotta pull the tube to swap the yoke though. 
|
|
| Back to top |
|
|
secstate
Joined: 20 Mar 2006
Posts: 720
|
| Posted: Thu Apr 30, 2009 4:57 pm Post subject: |
|
|
|
Curt, thanks for the input. I will try the SMPS tonight I hadn't thought that would have any impact. And you did jog my memory as I did have the skew, but not "smile" problem with my Barco Data 808s on the red as well. There I did have to split the different between horizontal and vertical skew but convergence was fine after that. It is really the "smile" bend that is causing my convergence issue. It magnifies any horizontal skew and on the left side of the screen I end up with an inch or two of red that is about half a line misconverged. Well at least if I have to swap a tube with the projector on the ceiling this looks to be the easiest projector to do it in.
|
|
| Back to top |
|
|
secstate
Joined: 20 Mar 2006
Posts: 720
|
| Posted: Sun May 03, 2009 2:22 am Post subject: |
|
|
|
Just thought I would update this thread for posterity in case anybody else has this issue. I swapped out the SMPS and it made no difference. Next I checked board on the lid with the deflection switches. In this model it is a fairly simple board so I just used my ohm meter and compared resistances on the red portion to green and blue. There were no differences it was a crude but effective quick test. So I finally swapped the red tube. I have to hand it to the Barco engineers they did this right, it literally took me 10 mins to swap the tubes while the projector was on the ceiling. Barco, my hat is off to you. In any case the tube swap fixed it. Since the other tube came out of my spare chassis it also came with its own yoke and focus coil. The new tube/yoke/coil fixed it, so it could in theory have been the tube, the yoke or the coil. Whatever the case, I can finally get back dialing the projector in. Who would have thought this would turn out to be a 2+ month long project.... lol
|
|
| Back to top |
|
|
zGman
Joined: 22 May 2006
Posts: 599
|
| Posted: Sun May 03, 2009 3:17 am Post subject: |
|
|
|
Check the focus yoke on the "old" red tube...Is it a KF-3205G?
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
|
| Back to top |
|
|
secstate
Joined: 20 Mar 2006
Posts: 720
|
| Posted: Sun May 03, 2009 2:42 pm Post subject: |
|
|
| zGman wrote: | | Check the focus yoke on the "old" red tube...Is it a KF-3205G? |
Just looked at the removed tube and it is indeed a KF-3205, I assume that is the correct one? The two Barco were purchased as a pair, have nearly sequential serial numbers and do seem relatively unmolested.
|
|
| Back to top |
|
|
zGman
Joined: 22 May 2006
Posts: 599
|
| Posted: Sun May 03, 2009 6:43 pm Post subject: |
|
|
OK - the other possiblilty is that the polarity on the convergence connector
was inadverdantly reversed. The geometry (bow/key/skew/etc) all work
thru interpolated convergence, and in my experiments with different
convergence coils on the Marquee chassis I saw similar effects with
polarity. I just checked the Barco connector - it is wired outer to outer,
and inner to inner, so reversing it would reverse the direction of all the
geometry corrections - top to bottom, and side to side....
G
|
|
| Back to top |
|
|
secstate
Joined: 20 Mar 2006
Posts: 720
|
| Posted: Mon May 04, 2009 2:28 pm Post subject: |
|
|
|
It is possible a wire was wrong. I did remove the red tube at one point and put it back in. I thought the Barco cables were keyed but it is possible I messed up.
|
|
| Back to top |
|
|
|
|
