CurtPalme.com Home Theater Forum

[Francisco]

Hi Greg,

Peaking was turned off indeed. Standard OEM Green Panasonic LUG but sharpness is excellent IMHO. Only BW SMPTE 1:1 pixel could be better compared to Marquee, but will see what happens after RGB amp mod.
Already canged the original cables for these shielded Belden cable with Canare BNC connectors some months ago.

[redfox001]

I have been thinking about these cables too and perhaps would take out the video completely and arange everything in a way to make a very short video connection right through the ceiling into the housing bypassing all external connectors

[stridsvognen]

[barclay66]

Hi,

The bandwith of the complete video chain is determined by its weakest link and this usually are the output stages on the neck boards. Their limitation is caused by the large voltage swing they have to produce and the required slew rate of the output amplifiers (usually measured in V/µsec).
More about this here: http://en.wikipedia.org/wiki/Slew_rate
Just imagine: An amplifier capable of 800MHz bandwith at an output level of 0.5Volt peak to peak (= 1V swing) has a slew rate of 3500V/µs (e.g. datasheet of the CLC111). For an output swing of 100V (not unusual for a neck board) it would need almost 100 x this slew rate in order to amplify at the same bandwith. This is where physical limits collect their toll.

So: If the neck boards remain unmodified, the complete video chain's bandwith won't improve significantly...

Regards,
barclay66

[geisemann]

The Signal path of the 909 goes in this order

Input BNC Jacks> Motherboard> Board Connectors> Switcher input transistor ( different for port 3 vs port 5)> Switcher opamp gain of 2> Interconnect cables> RGB driver gain of 5> Board Connectors> Interconnect coax> neck cards.

That being said the original port 3 input transistor on the switcher card is poor. We had to remove this and use a 5 GHZ transistor on port 3 to resolve more BW. The original port 3 went though 3 transistors that were all below 200 MHZ so using the port 3 alone on a 909 is horrible and at a min port 5 should always be used. The original port 3 was designed in late 1980 or early 1990 and was never changed and carried though all the barco modules including the old 800. This card went into a old Barco TTL switcher box that many customers used so barco had to induce this box in order to provide a quick plug and play design as a update. This old box and interface was horrible to say the least.

If you had a very early 1209, 800 model in some cases the port 3 actually gave you a better image but there was easy fix for that.

When the mod is made the port 3 input on the switcher card is removed and upgraded to a 5 GHZ input. Then the following path to the opamp to get it ready to move to the RGB driver card is put though a opamp gain of 2 and we remove this amp and replace with a 2.5 GHZ opamp to replace the old HFA1100 700-800 MHZ amp. This cleans up the input on the entire input stage.


BW is a function of making the first stages of the amp at a much much higher BW than the final stage. That's why audio amps with Vacuum Tube input stages with solid state output make a good pair because a tube has a very low input capacitance and excellent BW. Giving you a warm full sound.

Video amps are the same principle. The new BW of the projector will be a function of the entire chain. This figure 120MHZ RGB BW of the final stage depends on the input stage, input interface and source etc. So measuring this would require some baselines we don't have any data for so I cant verify this number and again we don't know the input resolution of the test. I was able to measure some BW over 190MHZ but again these numbers mean nothing if you have poor tubes or bad focus ....

I would say the barco neck cards on the 909 are superior with the custom output chip to say a 1209s.

Whats interesting is the old 1209G had a very well designed neck card with high BW. The tubes were not P19lug so they were soft and the back stage was poor. We have done many upgrades by re-wire the neck cards on a 1209G with P19lug simulation guns ( small aperture spot) and upgraded the back stages of the 1209G and had amazing results to the point where its almost sharper than a 909. So you can take a older Gen projector and work off its strengths. The 1209G with upgrades will have a far better BW than a 1209s.

www.eisemann-theater.com

[stridsvognen]

Greg can you try post some screen shots of your test setup, showing a 1080P 72 hz 1:1 verticaland horisontal lines. so we finaly can see how its surposed to look like. ( closeup )

That should be possible with 190Mhz bandwidth.

What us that dont have a 909 wonder is why no one ever post a screen shot where 1080P 60hz is resolved right. Not even with all mods instaled.

You must be the man who can do it, and ill guess a prove like that will make quite a few BARCO guys jump on your mods.

[CasetheCorvetteman]

[CasetheCorvetteman]

[stridsvognen]

[CasetheCorvetteman]

Stop being a dickhead.

[redfox001]

[redfox001]

By the way I came up with a crazy idea the other night to make a stock CineMAX more silent. Why not split the convergence tray's plugs? That way the convergenc/focus unit can be placed elsewhere (with these fans) and all you have to do is make these connectors between the tray and the motherboard a meter long. Still just an idea to think further about. Someone take a shot please

[geisemann]

HI

I went though a lot of different cables to connect the RGB switcher to the RGB driver and had to find a cable that was larger and better PF per foot but not too cumbersome. I took the old cable and put it on my Cap meter. RG6 would be great but way too large and be impossible to close the projector back hatch.

I found one that was small but had low loss. There are several types that are small but the loss was too great and not worth the upgrade. The outer jacket was large and the differential between the center conductor and the outer shield was not. So you had to find a cable that was not rated to be external but internal. There are not many left at this point as digital electronics have taken over so internal interconnects coax is difficult to locate. You want to select a cable with a small outer shield but a large inner insulator. This provides less PF per foot and able to increase BW.

This selection of cable was hard to locate worse than the actual replacement transistors in the input section actually!

If you are referring running RG6 to the back connectors ( port 5) of the projectors its a OK interface but you are better off running straight HDMI to the projector. No matter how good the cable is you will have PF of loss to muddy the picture.

The HDMI internal interface I designed bypasses the motherboard of the projector, connectors and also cable loss and it is matched to the switcher so its extremely clean and sharp. I did this experiment years ago after getting noise and focus problems using the port 5 BNC in the back of the unit.

I hope that helps.

Greg

www.eisemann-theater.com

[redfox001]

[CasetheCorvetteman]

See in my case using RG6 straight from the PC, it is a better option than HDMI to the MOOME V3 external. Its noticable.

Fox, i cant remember the name of the thread, it was a while ago, Mike posted a fair few pics of his modded Marquee with the same pattern.

[Francisco]

[CasetheCorvetteman]

Not yet mate, i just havent had the time to get it organized with Greg. The easiest way for me would be if i can get a full set of modded boards outright instead of sending mine from Australia to him for mods.

[stridsvognen]

Hey Case, did you ever make any screenshots with the right 1:1 pattern where vertical and horisontal have the same level from the source.?

[Francisco]

[stridsvognen]