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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed Oct 13, 2010 8:46 pm Post subject: |
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my new board works!!
still have lots of noise in the picture but thats probably a grounding issue.
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marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed Oct 13, 2010 9:41 pm Post subject: |
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????
now i get vsync out of range with the pc to bnc connected but when using the moome in the modified vim all is well what am i doing wrong.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Wed Oct 13, 2010 9:50 pm Post subject: |
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my regular vim gives the same message now with the bnc connected.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Thu Oct 14, 2010 12:59 am Post subject: |
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can 0,6 volt out of the bnc vsync be too low to cause the pj not to sync
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Thu Oct 14, 2010 2:53 pm Post subject: |
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the videocard seems to be the problem.
when raising contrast the picture crushes (on the modified vim and the known working vim), it never had that before so maybe its a voltage issue or my power supply in the pc is degrading.
with the ps3 i havent got this issue.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 15, 2010 9:32 pm Post subject: |
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i have populated all 3 channels and now only red works properly
when only green was populated it worked fine.
when increasing contrast suddenly green and blue go black (at value 30 and up) and red just gets brighter like it should.
any ideas what this could be.
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Oct 15, 2010 9:43 pm Post subject: |
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| dvh99 wrote: | i have populated all 3 channels and now only red works properly
when only green was populated it worked fine.
when increasing contrast suddenly green and blue go black (at value 30 and up) and red just gets brighter like it should.
any ideas what this could be. |
No, but I would start with adding grounds straps to the PC board. Tooo many of the grounds on that PC board appear to be floating. High bandwidth IC's need a LOT of grounding around them. They even need grounding one the other side of the board.
So the more of better you ground things, the better it'll perform.
High Bandwidth OP Amp are very finicky to work with. Sometimes it requires several attempts at board design to get them to perform properly.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 15, 2010 10:23 pm Post subject: |
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hi mike i found the problem but you are right that grounding is very important i have experienced this now.
i put the 2 signals going to the ad834s wrong.
green contrast on green and green on green contrast (pin 1 and 8)
same for the blue.
i now have a stock configuration with all clc449s but will now try to get the ths3201 to work but i do need some 10 to 50pf caps for that and i dont have them.
i have to place a 10pf across the feedback resistor of 715 to get the oscillation away.
btw it works great and is already outperforming my 02p vim.
1 on 1 off looks great... better then craigs g90 
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 15, 2010 11:05 pm Post subject: |
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on off
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Fri Oct 15, 2010 11:48 pm Post subject: |
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| dvh99 wrote: |
i have to place a 10pf across the feedback resistor of 715 to get the oscillation away.
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I'm thinking putting that cap across the F/B resistor will get rid of the oscillation, but it should also effect the performance of the chip.
If you're doing this on the board that you're working on, you don't need to go with a chip as finicky as the 3201. Again, it's a very difficult chip to work with, and it's really not needed in that stage of the video chain. You'll want to replace the 449 with a newer lower noise chip, but you don't need one of the super bandwidth chips to replace it.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Fri Oct 15, 2010 11:50 pm Post subject: |
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opa695 or el5166?
whats better
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Sat Oct 16, 2010 12:04 am Post subject: |
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| dvh99 wrote: | opa695 or el5166?
whats better |
695 is also finicky. 5166 would be better, but you'd have to try it and see how it would behave.
The 5166 is good for the first stage (right after BNC's). For the last stage on the VIM, go with something with a bandwidth rating below 1ghz
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Sat Oct 16, 2010 12:28 am Post subject: |
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just tested the el5166 on the red channel on my board without any resistor changes and it works perfect.
i think i will go with el5166 all the way first, looks like a safe bet.
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jantje112
Joined: 17 Jul 2006
Posts: 328
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| Posted: Sun Oct 17, 2010 11:59 am Post subject: |
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If you had responded on your pm's a little you had the el5166 and sma/b connectors.
I have about 20 of then lying around.
Nice effort on the project btw
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Sun Oct 17, 2010 1:31 pm Post subject: |
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heb je mijn berichtje al gelezen in je postvak jan?
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Sun Oct 17, 2010 4:22 pm Post subject: |
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The high bandwidth opamps (current feedback) are designed for specific values of feedback resistors at the desired gain. With these resistor values the bandwidth will be flat to the limits of the opamp (with proper PCB layout) with out peaking or early roll-off.
For gain = +2 and power = +/- 5V feedback resistor for the following opamps:
CLC449 = 250 ohm
EL5166 = 250 ohm
OPA695 = 511 ohm
THS3201 = 715 ohm
When the feedback resistor is higher value than nominal the bandwidth is decreased.
When feedback resistor is lower value than nominal peaking/instability occurs and may cause oscillations.
So, if the circuit is set-up for CLC449 and OPA695 or THS3201 is substituted peaking, instability, and/or oscillations are likely.
If the circuit is set-up for THS3201 and any of the above opamps are installed the available bandwidth will not be realized.
The feedback resistor works with the gain resistor. If one is changed the other must also be changed to maintain bandwidth and gain.
Scott
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Sun Oct 17, 2010 5:07 pm Post subject: |
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He had already indicated changing the resistors here:
| dvh99 wrote: |
i now have a stock configuration with all clc449s but will now try to get the ths3201 to work but i do need some 10 to 50pf caps for that and i dont have them.
i have to place a 10pf across the feedback resistor of 715 to get the oscillation away.
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So I assumed he was doing it for them all. Either way, the 695 and 3201 are very finicky on the Marquee VIM. And it gets worse if you try and use them on the neck boards, where you can't so easily swap out the resistors.
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dvh99
Joined: 25 Dec 2009
Posts: 2158
Location: nederland
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| Posted: Sun Oct 17, 2010 7:25 pm Post subject: |
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its working very fine right now.
it is still on a test vim with the clc 449 in the first stage but i will put them on my own vim which has the el5166 in the first stage as well.
i still want to get some caps in the 4 to 50 pf range to play with and some inductors that jarmo used instead (56uh) of the 4r7 resistors.
decoupling on my own vim is better now the test vim only has the 100nf at the 5volts.
scott when using the ths3201 in the first stage nashou told me to change out dc restore resistor r127(gr channel) 1k2 with a 3k3 when using ths3201, do the el5166 opamps need the dc restore resistors to be changed.
edit:
mike on my neckboards i have the el5166, but i didnt see much improvement just a little, let us hope that with a better front stage the difference will be greater.
thanks
dennis
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Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
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mp20748
Joined: 12 Sep 2006
Posts: 5689
Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
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| Posted: Sun Oct 17, 2010 7:58 pm Post subject: |
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| dvh99 wrote: |
mike on my neckboards i have the el5166, but i didnt see much improvement just a little, let us hope that with a better front stage the difference will be greater.
thanks
dennis |
You're right. It really depends on the level of performance before the neck boards.
| Nashou66 wrote: | I did not change them at all with the El5166's they work great as a drop in chip.
Athanasios |
The 5166's are the best and closest replacements out there for the CLC449's. And since they both share the same value FB/G resistors, you only have to replace them. But that's may not be the case on the second stage of an 03 VIM.
The 5166 is a far better chip than the CLC449, and because of it's better performance, it's more likely to pick up some noise from a noisy CLM or other area in the PJ.
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