CurtPalme.com Home Theater Forum

[Curt Palme]

OK, I've run across something I've never seen before.

I was working on a planetarium system that uses 6 Barco 1209s projectors running at 59Khz/60Hz in a 6 projector blend.

Due to the dome that the CRTs are projecting on, the top bow needs to be at 0, or very close to 0.

Now, as an aside, normally the AKB line on Barcos is above or below the tube face, so you see a faint flicker along the edge of the tube face, but the AKB line doesn't come into the image at all. What I found with 3 of these sets is that ONLY at 60Khz (or so), when the bow is at 0, the AKB line comes into the tube face, and into the top of the image. The line is very dim, but in a 0 brightness planetarium situation, the line appears on the dome as a faint 'UFO' (as we called it), and it's annoying.

What I found on the bench is that only the scan frequencies around 60Khz do this, and that's of course where the planetarium system is running at, and it can't be changed. I used the internal test patterns, and on two sets, I had the line appear between 60 and 65 Khz only. It didn't seem to come into the image at resolutions lower than 50Khz.

Can those of you that have Barco 1209s (or the Runco equivalent) try running the internal 64Khz test pattern, set the top bow to 0, and see if you get a visible line at the top of the image, then take the bow control towards 50, and confirm that the line goes away?

I'll be emailing Barco shortly on this as well. Never seen this before, it's annoying in this application, but no one in a home theater mode will ever run across this...

Thanks!

[Curt Palme]

OK, I've run across something I've never seen before.

I was working on a planetarium system that uses 6 Barco 1209s projectors running at 59Khz/60Hz in a 6 projector blend.

Due to the dome that the CRTs are projecting on, the top bow needs to be at 0, or very close to 0.

Now, as an aside, normally the AKB line on Barcos is above or below the tube face, so you see a faint flicker along the edge of the tube face, but the AKB line doesn't come into the image at all. What I found with 3 of these sets is that ONLY at 60Khz (or so), when the bow is at 0, the AKB line comes into the tube face, and into the top of the image. The line is very dim, but in a 0 brightness planetarium situation, the line appears on the dome as a faint 'UFO' (as we called it), and it's annoying.

What I found on the bench is that only the scan frequencies around 60Khz do this, and that's of course where the planetarium system is running at, and it can't be changed. I used the internal test patterns, and on two sets, I had the line appear between 60 and 65 Khz only. It didn't seem to come into the image at resolutions lower than 50Khz.

Can those of you that have Barco 1209s (or the Runco equivalent) try running the internal 64Khz test pattern, set the top bow to 0, and see if you get a visible line at the top of the image, then take the bow control towards 50, and confirm that the line goes away?

I'll be emailing Barco shortly on this as well. Never seen this before, it's annoying in this application, but no one in a home theater mode will ever run across this...

Thanks!

[nombz]

I ran out and tried on my BG1209s (/E which might matter) and I dont have any line whatever I do with top bow in 64kHz internal pattern (not on screen, and not when looking directly into the tube face).

[TbX]

you can not just turn off the AKB and run without it
I do not think there is a setting for where the AKB line shall be

[Tom.W]

[secstate]

My Runco 1100 does this at 960p (which is right on 60KHz/60Hz). My top bow is around 10 and two out of the three tubes did this. You could only see it on a real dark or black scene. I tweaked some of the settings in power strip and got it to go away. If you find another solution let me know. Oh and you are wrong I DID run into this in my home theater .

[stefuel]

Where's Gary when yo need him

[Curt Palme]

Thanks, so this seems to be an issue with the design, and not the set I sold. That's what I figure, given that 3 chassis have done it. The two Barco people haven't replied, there's gotta be a fix for this..

[Curt Palme]

Thanks, so this seems to be an issue with the design, and not the set I sold. That's what I figure, given that 3 chassis have done it. The two Barco people haven't replied, there's gotta be a fix for this..

[jkruger]

My Runco 1100 does it too.

[TbX]

Have you tried to run it in hi-band and see if the line moves
do you run the projector in ceiling or table mode
when I have my 1209S in the ceiling mode and bow to 0 no abl lines
but if I put the bow of 99 they come up

[Ile]

If you can't chance sources vertical timings to chance line position, adjust projector to scan in high freq mode to see if it have any affect to problem.

Turning ABL off would be last option. As you probably know 808 have S1 switch in vertical deflection board to turn ABL off, but 1209s don't have this switch. Maybe this 808 feature gives you idea how to disable it from 1209s...

[Curt Palme]

Thanks, I had Tomas from Sweden suggest that yesterday as well. Right now I do not have a G1209s here, but I have 7 coming in next week, so I'll try the high band, and will see if I can disable the AKB if not. BArco has gotten back to me, the fellow is going to check his notes to see if BArco came up with a workaround..

[Curt Palme]

Thanks, I had Tomas from Sweden suggest that yesterday as well. Right now I do not have a G1209s here, but I have 7 coming in next week, so I'll try the high band, and will see if I can disable the AKB if not. BArco has gotten back to me, the fellow is going to check his notes to see if BArco came up with a workaround..

[Curt Palme]

OK, I got an email back from BArco. There is apparently a 'fix' to correct this from Barco. I have partial service notes right now, I'll get more from them soon.

If there's interest, I'll post what it is, or I will offer a mod service in case anyone wants it done that can't solder.

They seem to be mods to the V board. Not sure if it turns off the AKB or changes it, but it looks like it's what I was looking for to fix this.

[Curt Palme]

OK, I got an email back from BArco. There is apparently a 'fix' to correct this from Barco. I have partial service notes right now, I'll get more from them soon.

If there's interest, I'll post what it is, or I will offer a mod service in case anyone wants it done that can't solder.

They seem to be mods to the V board. Not sure if it turns off the AKB or changes it, but it looks like it's what I was looking for to fix this.

[WTS]

Yes post whatever it is you get from Barco, thanks

[Curt Palme]

Here's the info for the very new SMT style V boards as used in the 808 (and 812). I've never seen the EMT boards. Use this info at your own risk:

There is now also a vertical deflection without subunit and in SMD technology. This is part number R762808 (808 series only thus also 812)
For the R762808 the modification is more easy to do. Check if P402 is fitted. If so adjust P402 to remove the ABL lines till no more visible.
If you see no P402 fitted on the circuit board proceed as follows to implement the hardware for ABL removal.

• Fit potentiometer P402 (20K) on the circuit board. The text is already screened on the PCB.
• Remove the 2 SMD resistors of zero ohm just underneath P402. The text printed on the SMD resistors is 000.
• Adjust P402 till no more ABL lines visible.

[Curt Palme]

Here's the info for the very new SMT style V boards as used in the 808 (and 812). I've never seen the EMT boards. Use this info at your own risk:

There is now also a vertical deflection without subunit and in SMD technology. This is part number R762808 (808 series only thus also 812)
For the R762808 the modification is more easy to do. Check if P402 is fitted. If so adjust P402 to remove the ABL lines till no more visible.
If you see no P402 fitted on the circuit board proceed as follows to implement the hardware for ABL removal.

• Fit potentiometer P402 (20K) on the circuit board. The text is already screened on the PCB.
• Remove the 2 SMD resistors of zero ohm just underneath P402. The text printed on the SMD resistors is 000.
• Adjust P402 till no more ABL lines visible.

[Curt Palme]

and for the older 808 V boards:

R7622686 :
 Remove C132
 R179 becomes a bipolar elco of 10 uF / 25V
 R50 becomes 1K
 R130 becomes 22K
 R131 stays 33K (increasing R131 will shoot the lines higher)

[Curt Palme]

and for the older 808 V boards:

R7622686 :
 Remove C132
 R179 becomes a bipolar elco of 10 uF / 25V
 R50 becomes 1K
 R130 becomes 22K
 R131 stays 33K (increasing R131 will shoot the lines higher)

[secstate]

Curt thanks for posting the details. I have a spare V board so might just mod that one, on the other hand since powerstrip is working for me, maybe I will leave well enough alone

[Decibel]

[Curt Palme]

The 5 doesn't mean anything, it just means it's a slightly later version of the board. THe mods will work on that one as well.

I have seen that 808 board before pictured above. It's out of a post 2000 (or so) 808 chassis and uses a lot of SMT components compared to discrete parts.

[Curt Palme]

The 5 doesn't mean anything, it just means it's a slightly later version of the board. THe mods will work on that one as well.

I have seen that 808 board before pictured above. It's out of a post 2000 (or so) 808 chassis and uses a lot of SMT components compared to discrete parts.

[Decibel]

The pots of the R7628085

[Decibel]

P402 area