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[tschaeikaei]

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Because you asked me about it: Here is something about the fan mod I did to my marquee.
It should be applicable to every other CRT projector at least the last part (the fan control).

The easy part, LVPS fans

I use temperature controlled Artic F9 pro TC fans in the LVPS.
They are quieter than the original NMB fans and come with a tiny temperature sensor on a long cable.
I changed the temperature curve a bit, they normally are at full speed if the sensor measures 38°C.
I increased the temp a bit by adding a resistor to the sensor wire. They now start at about 38°C and are at full speed
at 44°C. Thats plenty of cooling and yes, they are much quieter than the NMBs, even at full speed.
cf/min and static pressure are about the same as the original fans have, the Arctics have better shaped wings and bearings
and that's what makes them quiet. Not to forget about the rubber suspension they have. And that is what made me buy them in the first place.

Discussion about the LVPS-fans here: http://www.curtpalme.com/forum/viewtopic.php?t=34801
But, simply use them, i did it for two years now and it does work really nice.

Here are the fans.




Part two, the mechanical changes

As i mentioned in the previously linked thread on page 127 or so, I had the idea to thermally couple the aluminum boxes of the HDM and FGM to the big heatsinks on the boards.
There isn't much work or knowledge involved. You need ONE flat piece of aluminum (190x50x5mm), some threading tools (drillbits, tap and countersink), drill and some screws.
Some additional thermal compound is nice, but not absolutely needed. Unscrew the top cover of the projector, remove the HDM and FGM covers and take the boards out.
Now use a long philips screwdriver to unscrew the single screws outside the boards facing towards the lenses.
Take the boxes out, stick the boards back in and use your electrical drill. I did two rows of 5 holes per board to archieve much heat transfer between box and heatsink.
On the FGM you need to additionally use your piece of aluminum between heatsink and box (there is a gap between them).
It's that simple.


On the pic: FGM cage from above, you see the aditional flat aluminum between heatsink and box.
Don't worry about any electrical shorts or so, heatsink and box are electrically connected by a flat grounding spring contact.
You will just improve the electrical link between them. Sure it is needed to clean the boards after drilling and threading. But i'm not talking to schoolgirls here, am i?

Part three, the improvement of the thermal conductivity of the backside boards
I did some measurements (in the original condition) on these three (astig, convergence and vertical deflection) boards, too.
There are two rows of transistors and some of them get hotter then the others. I had about 60°C on some of them while others did only warm up to about 42°C or so.
The big backside heatsink where they sit on was about 40°C at that time. What does this tell? Yes, the thermal connection is not the best.
And the biggest and best heatsink is useless if the semiconductors that should be cooled get too hot.
Yes, 60°C will not kill them, but we want to settle (especially) convergence as fast as possible after warming up and not drift around for a whole movie.
I bought thermal tape with the best conductivity i could find, cut it in stripes and used it instead of the original stripes. I added minimal thermal grease,
reinstalled the board and the transistors that were at 60°C before, only were at 42°C after that. That alone was a lot of improvement in convergence drift.

Then, i took the tubes out, removed the three NMB belly fans and the aluminum sheet they sit on. I covered every bottomside of the tube housings with tape,
which means i deactivated the original airflow system completely. I would have been enough to cut the fans wires or to simply disconnect their (common) connector.

Part four, an electronic trick

Let's get to a scientific point of view.
What is demanded when you want to cool a CRT projector?

- It should be as quiet as possible
- It is not needed to get the thing as cool as possible
- It is needed to achieve a stable temperature after warming up time, which should be as short as possible.

The second and third argument are related. So why not as cold as possible? Because that would make fast spinning, enormous fans necessary.
But how do you achieve a short warm up time?
... Easily. Or not... go on reading
If you want to get every part of the projector to heat up to a certain temperature and accurately stay at that temperature,
you are in the need of a temperature controlled cooling system.

The fans should be OFF when the projector is cold and after warming up spin only so fast that the temperature doesn't further increase.
Sure, this is not possible with a static setting. E.g. the HDMs heat will increase if you use various refresh rates or horizontal frequencies.
All setings will change from summer to winter ( it does make a difference if the sourrounding air is 17 or 30°C).
So, each warm part of the pj needs a pair of a temperature sensor and a fan. Each pair controlled and individually adjustable.


So, we build a microprocessor- driven fan control with six channels (one channel per sensor/ fan pair)
We use an USB-serial- converter to set each channels temperature to a desired value. If the temp is lower than that, the fan is off.
If the temperature slowly reaches the desired value, the fan will slowly start spinning and after a few seconds reach a constant rev/min.
Why does it not turn full speed, the digital control can only turn on and off the voltage? Read on, i will explain that.

There is an additional channel, that is not used for fans or temp sensors. It is connected to a LED and a piezoelectric speaker.
If a critical temperature is reached, alarm kicks in. All fans will then spin at full speed, the LED will flash and the speaker will ... speak.
No, it will beep. ("Alarm, alarm" may be available in a future software version).
The alarm temperature (which is programmable per USB- user- interface, too) is sure set far above the other temperatures.
There is a low-temp alarm, too. It is used to prevent from connection failures between the controller and the fans or sensors.
If the microprocessor measures a temperature below 10°C (which is about 50 deg Fahrenheit), it interprets that as a not connected sensor.
Beep, flash and so on. The failing channel will be specified via the USB- interface.

Additionally needed is the following: 12 to 15V power supply for the fans (i didn't want to use the internal -24V in the Marquee the original fans are connected to.
You would be allowed to connect your USB interface (potentianl problems through the laptop and ground of the laptop charger.
Between LVPS and HVPS is plenty of room for a cheap Meanwell SMPS. I connected the power supply to the mains input (inside the LVPS) and thats it.

So how does it work? The microcontroller runs through a routine thousands of times per second. In every routine, it measures the voltages (=temperatures)
coming from the sensors. Every time it measures, it will measure an other value. E.g. first time 30.00°C, then 30.03°C, 29.95°C, 30.01°C and so on.
If we set our desired temperature to 30.00°C it will give the following effect.
Because the microcontroller switches the corresponding fan on (if >30°C) and off(if <30°C), the fan will be sometimes on and sometimes off.
And because this all happens several thousand times per seconds, the fan, our ears and our eye will not notice it.
EMC- troubles? No, the fan connectors are parallel with some big enough capacitors which flatten the voltage peaks.

Fan control board with six sensor connectors and six fan connectors, the alert LED and the beeper. It sits on the backside of the (green) neckboard cage.



Part five, many fans

So i mentioned to have 6 independent channels on the control board. That means, i use six fans and the corresponding six temp sensors.
One 120mm fan on every tube housing to cool the tube itself and the neckboard. One 80mm on each the HDM and FGM and one 140mm on the big backside heatsink.
The size of the fans does only make sense in that configuration. The tube cases are about 115mm wide and the HDM and FGM boxes are small. The hole isn't event big enough for
the 80mm fans, but some kind of funnel will be made to lead the airflow. Our friend Barclay did it the same way as i did and soldered some copper funnel he will maybe show us.
In fact, he is the father of this idea i want to thank him for.
You see that the tubes fans sit approximately at the middle of the housings blowing air into them. one half of the air comes out at the front (towards the lenses, which cools the tube itself.
The other half goes to the neckboard at the backside.
The backside fan is a simple thing: Cut out the corresponding hole, use some rubber pins to mount it. I did use additional foam between the fan and the metal sheet, which is nice, but not totally necessary.
It blows air to the big heatsink, the FGM and HDM fans blow into the boxes.

Now you will maybe think that all the air that is sucked from underneath (pj hanging at the ceiling) is pumped into the projector and stays there.
No. The big backside fan doesn't pump anything inside, it will come off through the holes in the backside metal cover again. The tubes fans will blow half of their air out to the lenses.
The other half goes inside the pj. This is the only negative argument on my system (besides of cost and effort) i found so far.
The air blown into FGM and HDM will be sucked from underneath the pj (from outside the case!).



the types i used:
140mm Cougar Vortex (CF-V 14 H, on the backside) http://www.cougargaming.com/products/fans/vortex_hdb.html
Very good fan, much air, nearly inaudible, very good bearing
120mm Cougar HDB fans (CF-D12HB, on the tubes)
Very good too, but i like the Vortex better.
The Cougars have rubber pads around the screw holes, which makes it easier to mount them vibration-cushioned.
They come with rubber pins to mount them, which (in case of the HDB series) are too thick and brake when using.
You will have to use other pins or enlarge the holes (by 0.5mm or so).

80mm Enermax TB Silence http://www.enermax.de/produkte/luefter/tbsilence/
They are ok, not good. Would buy them again but use them for the first time.

Thanks to Nash for telling me about the cougar fans.

Regards, Julian

[redfox001]

Thanks for the info. What kind of tape did you use?

[tschaeikaei]

3W/mk 0,15mm heat transfer foil. 4 pieces of this stuff.
But there is even better stuff on the net. You have to cut it in 20mm stripes
for the Marquee. 6 stripes of 100mm are enough for one projector.

ebay

[tschaeikaei]

So if i can say it that way: i am interested if someone could use that kind of fan controller, too.
I could imagine to build some more, but i first need to know if there is demand on that stuff.
And no, i don't want to get rich.

Regards, Julian

[redfox001]

I would need something to get the temperature on the heatsink lower not necessarily more quiet. Would that work?

[tschaeikaei]

Possibly. But I need more info about that, Redfox.
What always is a good starting point is measuring the heatsink temp vs. transistor temp.
That means in fact measuring the thermal coupling between the part and the heatsink.
It should not differ more than about 2 or 3 degrees.

My initial idea about the fan controller was to eliminate temperature caused drifting of the semiconductors.
This was more important to me than overall fan noise.
But fan noise is in fact much much lower than it was with the original system.
And I think that's most important on blend and stack solutions of CRT projectors.

Regards, Julian

[redfox001]

Ok. My 9500 is really bad. It got pretty cold a few days ago and when I started convergence was all over the place. Reconverging and than drifting and than was all wrong again aaaaarh! I am pretty sure it has something to do with my chassis and the environment temperature. I did some things with my Frankenyokes and I have to take them apart again. Now i know why there is so much space in the housing of the yoke. It has to be able to expand I guess. If that is not it than the whole chassis is wrong. Hard to find.

[redfox001]

I am trying to understand what you did but when I read

[tschaeikaei]

The reason is easy: I plan to hang the projectors upside down to the ceiling.
Then, using the original system, the airflow would be from the ceiling downwards through the projector.
I reversed it and since warm air from the projector can now naturally flow upwards, there is less heat
and less noise. So i can let the fans spin slower.
In the original system, every part that is cooled by the 3 belly fans gets the same airflow.
That means the FGM, HDM and all three tubes and neckboards.
But these parts don't produce the same amount of heat.
The tubes get more air than they need and the HDM and FGM don't get enough.
(If talking about 1080p or other high frequiencies)
And i can regulate each channels temperature independently.

The HDM and FGM fans spin a bit faster while the fan on the backside heatsink and those on the 3 tubes
spin very slow.

I could have turned the belly fans around, so that the air goes from top to the bottom (upwards if the projector is on the ceiling)
but that would mean that the fans suck the air through the tube housings.
And since sucked air has a cooling efficiency much lower than if you blow air on a heatsink,
it would mean you must let those fans spin faster than if they blow onto the heatsinks.

Is that what you meant?

If you are referring to the tape thing: If i didn't close those holes (with the tape)
the air would flow directly from the fan trough that hole to the ceiling.
and it would not cool the VNB and tube front heatsink.

Regards, Julian

[tschaeikaei]

Some update.
We've added a bluetooth module and a friend of mine wrote an android app. So it is possible to change settings via
the mobile phone and read out temperatures via that app.
Quiet nice.
I'vetaken some more pictures of the projectors on the ceiling and the extended control board.
Mainly to show how i placed the fans.
Note that the holes in the tube housings are taped. The holes under HDM and FGM boxes are open, so the warm air can flow to the ceiling.
Yeah, I've got to paint the case. Let me say that the black lacquer that VDC (or who else has done it) is absolute garbage.
It is scratched so easy, that it should be no problem to remove it before repainting.

Also note that this is not finished. Fans flapping around in the breeze are just for cooling while doing the toe in/center/ astig/focus coils thing. After that i will fit everything back together nicely, i promise

Regards, Julian

[Tim in Phoenix]

Hello

With regards to the lvps fans, do they run at all when the machine is cold? The lvps is "always on" supplying standby power to enable power-up commands. Also, the lvps fans cool the hvps, so the hvps needs continuous airflow when running.

[tschaeikaei]

Hi Tim,
The LVPS fans are not connected to the control board. I use temperature controlled fans that always spin.
They are connected to the 24V rail using an 7812 voltage controller.
They spin up to 2000rpm when the sensor sees more than 38°C, but they are always on (500rpm below 38°C).
See the first part of my first post on this page.
https://www.arctic.ac/de_en/arctic-f9-pro-tc.html
See the temperature/ rev curve on the bottom. I've modified it a bit using an additional resistor in the temp-sensor wire.
(38°C vs original 32°C spin up temp)
I recommend these fans strongly, if you want a simple temperature controlled solution.
My projectors have been equipped with these for about 2 years and no problems so far at all.
They are completely inaudible when not in full revs, but even there, they are just audible.
I've added no foam or other damping material to the LVPS, just the fans.
I know you've been professionally fan modding the LVPS and if you'd try what I've done.. would be really interesting.

Regards, Julian

[Tim in Phoenix]

Hello

If you are pleased with the results, that is great.

[tschaeikaei]

I am, definitely.

[maf]

[tschaeikaei]

I used 40x40mm, they are some kind of aluminum alloy, nothing really special.
It is adjustable in a wide range but two things i realized after hanging them up:
You should have much clearance between the two long (parallel to the screen) rods.
It's not that easy to slide the t-nuts in the slots if the weight of the projectors is on them.
It is possible, but use some force.
Good thing about the way i did it: projectors are adjustable every possible way.
You can slide them forwards, sideways, backwards and so on.
You can rotate them in all directions.
And it's rather cheap and the construction itself is only 80mm high.
Important, especially on low ceilings and tall projectors.
Thats a disadvantage of the Marquee, they are much taller than other projectors.
Barcos are about half as high.
Regards, Julian

[tschaeikaei]

Pictures of the new version of the fan controller.
The board itself connected to 6 sensors on one side and 6 fans on the other side.
Android app to read out temperatures, power (percentage) for the fans
and set different controller parameters.
Power=16 is zero, because it is the lowest possible value. The fan does not move at that voltage (about 1 or 2 Volts).
If the temperature raises, the controller will increase the fan power until the desired temperature is reached.

Some question: Do American people know how to use the Celsius scale? As we could calculate the values in Fahrenheit,
but if that is not necessary, we'll spare the time to do it.

In my setup, channel 1, 2 and 3 control/cool the R/G/B neckboards and tubes, ch 4 FGM, ch 5 HDM. The green tube (ch2) is always
radiating a bit more heat, just because it sits in the middle and the HDM and FGM radiate a heat in that direction.
So the more power on the green is explained. Maybe that's another reason why the green phosphor uses up faster than red and blue.
I hope to avoid (or slow down) that process keeping all tubes at exact same temps.

Ch6 is connected to the big heatsink where /vert./Astig/convergence boards sit on. That board rises temp very slowly.
Therefore, the temp you see is way below where the fan would start spinning. I took the screenshot about 2min after power up.
Projector was fed by 1280*1024 75Hz Contrast and Brightness 50.


Regards, Julian