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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Wed Oct 01, 2014 11:54 pm Post subject: CineMAX / 9 / 909 /919 convergence mods |
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| redfox001 wrote: | | CasetheCorvetteman wrote: | | You see exactly my point here between the Barco and the NEC fine adjustment sizes? I wonder if there would be a way to mod it so the steps could be finer in size at the expense of the totally unrequired amount of range you get!! |
When I look at the convergence board I see an input opamp that has a 1k resistor in its feedback. Seems to me that replacing it to something bigger would make the amplification smaller so you probable need 90 at the corners but the steps would be smaller. |
Lets look further into this...
The biggest thing holding me back from being totally happy is the very coarse adjustments Barco labelled as "fine". If we can make those steps smaller, pixel perfect convergence should be really easy!!
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Thu Oct 02, 2014 2:00 am Post subject: |
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I'll look at it over Christmas. I predict that things are about to get crazy busy for me, as I've quoted a bucketful of stuff recently. It is something I want to look into more, but not right now. got a stack to tweak!
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 2:23 am Post subject: |
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That would be great Curt, based on the section I quoted above it may be as simple as swaping a few resistors, I have had the tray out thismorning and looked, seems to be 6 surface mounted 1k ohm resistors on the under side of the board.
Id rather not go and make such changes without either your guidance or that of another very qualified person.
Im just looking now at what my largest correction away from center setting is on coarse adjustment, and will post back that info shortly.
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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CasetheCorvetteman
Joined: 09 Nov 2008
Posts: 6326
Location: Australia
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| Posted: Thu Oct 02, 2014 2:41 am Post subject: |
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My biggest difference it around 22 in the corners, although one on my blue is 26 away, top left corner. This could possibly be better corrected by adjusting my width coils, which I have never done.
Having said that, my blue tube has issues and requires a fair amount of raster shift to align it with the tube face.
Most of the coarse zones are in the 40s and 50s, so not much of the range is being used. Changing the amount of range by around 33% ( changing the 1k resistor to 1.5k? ) should reduce the steps more than enough to make it all nice and usable.
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Thu Oct 02, 2014 10:10 am Post subject: |
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Ok below is a small part of the schematic of the convergence output. Remember I am not an electronic expert so wait on what the experts say. I think I see an opamp I61 with feedback on its inverted input. Such an opamp has Gain 1 + Rf/Rg. See the picture.
Now Rg is the one connected to ground R63 with the value 1k3. Making it bigger would make the Gain smaller. Correct?
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Thu Oct 02, 2014 10:13 am Post subject: |
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Perhaps it is easier to lower the input by increasing R61?
By the way this has to done on 6 resistors for 3 colours x vertical and horizontal.
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 10:20 am Post subject: |
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Id have thought the 1k one in line with pin 3 on the opamp would be the better one to increase, but i dont know either.
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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redfox001
Joined: 16 Mar 2009
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Location: The Netherlands
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| Posted: Thu Oct 02, 2014 10:33 am Post subject: |
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| CasetheCorvetteman wrote: | | Id have thought the 1k one in line with pin 3 on the opamp would be the better one to increase, but i dont know either. |
If we asume the current going into the opamp would be very small than there would be almost no influence of changing that one I think.
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 10:36 am Post subject: |
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It should serve to reduce the voltage though
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 10:40 am Post subject: |
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| redfox001 wrote: | Perhaps it is easier to lower the input by increasing R61?
By the way this has to done on 6 resistors for 3 colours x vertical and horizontal. |
I dont think i would do the green, it may make it difficult to get the keystone correct, although the top and bottom bow and keystone can be very close to boarder line in terms of perfection, i havent had the same issues to the same degree with the sides.
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Thu Oct 02, 2014 10:49 am Post subject: |
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| CasetheCorvetteman wrote: | | redfox001 wrote: | Perhaps it is easier to lower the input by increasing R61?
By the way this has to done on 6 resistors for 3 colours x vertical and horizontal. |
I dont think i would do the green, it may make it difficult to get the keystone correct, although the top and bottom bow and keystone can be very close to boarder line in terms of perfection, i havent had the same issues to the same degree with the sides. |
Yes you are right. Only blue and red. This might work 
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redfox001
Joined: 16 Mar 2009
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| Posted: Thu Oct 02, 2014 10:51 am Post subject: |
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| CasetheCorvetteman wrote: | | It should serve to reduce the voltage though |
Don't think so. The voltage on the opamp side is almost the same as before the resistor because of the low current. I think this resistor makes a rf filter with the cap. I would not change it might even oscillate the opamp.
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redfox001
Joined: 16 Mar 2009
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| Posted: Thu Oct 02, 2014 10:59 am Post subject: |
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R61 is in a voltage devider with R62 making the voltage R62/(R62+R61).
You can calculate how much you would have to change R61 to get 10% decrease.
2k4/(2k4+4k7)*0,9=2k4/(2k4+R61)
I think 5488 Ohm or close for R61.
And I don't see how this could go wrong but be careful with these smd.
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redfox001
Joined: 16 Mar 2009
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| Posted: Thu Oct 02, 2014 11:10 am Post subject: |
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He you might just put a 1k resistor in the wire of the connector! Or even better a pot.
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 1:29 pm Post subject: |
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The SMD isnt really a problem, but i wont make changes on a whim, i need to be pretty sure first.
Put a resistor in line with the coil you reckon?
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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redfox001
Joined: 16 Mar 2009
Posts: 2257
Location: The Netherlands
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| Posted: Thu Oct 02, 2014 2:05 pm Post subject: |
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| CasetheCorvetteman wrote: | The SMD isnt really a problem, but i wont make changes on a whim, i need to be pretty sure first.
Put a resistor in line with the coil you reckon? |
No there is a connector with yellow wires between the controll board and the convergence output board. I once cut the vertical wire and connected to the horizontal for blue and visa versa to know if the control or the conv was the problem.
But what I mean is. You can cut the wires for blue and red horizontal and vertical and insert a 1k resistor. Wrap some tap and ready!
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CasetheCorvetteman
Joined: 09 Nov 2008
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Location: Australia
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| Posted: Thu Oct 02, 2014 3:12 pm Post subject: |
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Interesting enough theory, i wonder if it will work or if there will be any other side effects?
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Barco Cine 9, ,Sony VPL570ES 4K SXRD, 135" OZ Theatre Majestic 16:9 screen, Denon X6700in preamp mode, 2x 7ch Tonewinner amps, 2x Tonewinner 15" subs, 2x 10" subs, 7.2.6...
RUNCO DTV991 LC ( NEC XG 852 LC ) 100" 4:3 screen, H/K AVR 7.1...
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redfox001
Joined: 16 Mar 2009
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Location: The Netherlands
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| Posted: Thu Oct 02, 2014 3:14 pm Post subject: |
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| CasetheCorvetteman wrote: | | Interesting enough theory, i wonder if it will work or if there will be any other side effects? |
Just let it rest a day and see if anyone jumps in.
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redfox001
Joined: 16 Mar 2009
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Location: The Netherlands
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| Posted: Sun Oct 05, 2014 11:20 am Post subject: |
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| redfox001 wrote: | | He you might just put a 1k resistor in the wire of the connector! Or even better a pot. |
Did you try this? I can not see how this could do anything wrong. This means increasing R61 but not on the print but in the connector. The wires are labelled on the print so just try the RV. I calculated that 1k should make the steps 10% smaller.
What you do with this mod is to make the voltage from the controller smaller and the convergence sees a lower voltage. Thats all!
The controller is build to be able to deliver 100 with the mod it might have to deliver 90 and that should not be a problem.
The current is very small so a 1/4 watt resistor is alright.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sun Oct 05, 2014 12:32 pm Post subject: |
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| redfox001 wrote: | | Perhaps it is easier to lower the input by increasing R61? |
yes, this is the best idea to try.
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