CurtPalme.com Home Theater Forum

[redfox001]

Hi!

I am wondering if it is possible/preferable to completely remove the 4 fans behind the tubes of the G90 and get the airflow through a tube that goes through the hole in my ceiling to the attic above. The tube would connect to the whole back of the G90. I am hoping I can put a big fan on the attic that completely replaces these 4 fans.

The fan in front I was thinking of removing it and leaving a hole like I've read here and connect a tube that goes through the ceiling too? To this tube, again a big fan, would be connected on the attic pushing air.

I know I would have to monitor the temperature to be save but has anyone succeeded with this approach? I realize I am fortunate to have an attic readily accessible above the ceiling and I'm hoping to get this G90 as silent as a split pack or a digital.

Thanks for helping!

[CIR Engineering]

Sure, you could do it. Why not?

Like you say, just measure the temps before and after your system. You want the projector to run at about the same temperature as before the changes. I don't like running the projector cooler than stock either because it takes longer to reach steady-state temperature and the convergence never quite holds.

You've seen my front end cooling mods on the G90 (on my web page). I also have an extensive procedure that takes care of the back of the projector. I remove all the boards and chassis material, cut out all the metal grates from the chassis, and then put everything back. I install resistors in line with the stock fans to slow them down and quiet them. Removing the grates allows for more laminar airflow and less restriction so everything gets a lot quieter. With the front fan mod that you saw and the rear fan mods the projector is literally less than half as loud as stock.

With an attic system like you describe you could make the thing almost silent... just be sure to watch the temps. My mods make the projector slightly cooler, but I wouldn't want it to run any cooler than it does now.

On my G90 I also use a hush box. To vent, I cut holes in the ceiling and vented into the joists with two large 200mm computer case fans. The fans run off the G90 15 volt rail so they turn on and off with the projector. Between the hush box and the fan mods the projector is very quiet. I have left it on overnight a few times already because I can't hear it much when I get up to leave the room

craigr

[redfox001]

This gives me some very good idea's. I might replace the 4 back fans with silent fans and put potmeters between so I might run them slower. Than use one of the back fans for the front procedure like described before. That way I'm not doing anything unknown to CRT mankind and you the pro's By just running the fans slow and using an original fan in front I think the electronics does not have to be fooled and the power supply will shut the G90 down when the fan fails.

Than in addition the ventilation on the attic. The better that gets the slower the other fans can run.

Now I have to find a few suitable temp sensors.

And finally I might just add a hush box that is rather large like this and fill it with damping material like common wool.

Guess I will have to listen first to know how far to go

[CIR Engineering]

I recommend keeping the Japan servo fans in the back of the G90 if you are going to use fans. The Japan servo fans use a different protection circuit for fan failure than a PC fan. If a PC computer fan stops running it usually will not shut down the G90. I had my own G90 burn up the PE board in the front when my SilenX fan stopped spinning and the projector kept running (this is why I created my own fan mods). I have had a number of clients who have the same problem with PC fans in the back of the projector as well as the front. I just sold a new PE board to a guy in China because his PC fan stopped working in the front of the G90 and it fried the board.

Also, the Japan servo fans are designed to last for a very long time and PC fans just are not built to last. The PC fans will die at some point and you probably won't know until it's too late.

craigr

[redfox001]

Ok, thanks I understand that replacing the fans with pc fans is in fact a risky operation. I might use a NTC resistance of 5 Watt 100 Ohm or so that when it gets really hot the original fan runs faster? Has that been tried.
Than I might use external venting to get the temperature down making the original fan run slower automatically?

[redfox001]

I have one more question.

I might go the other way and try to split the G90 and the tubes

When I look at the layout of a split pack 919 it seems they just connect the wires from the neck boards and focus units to a big connector on the case and the high tension splitter is having its own cable through a separate hole in the case. On the outside it is one cable.

What I might try is placing the complete beamer with the housing and all the fans on the attic. So all the electronics is cooled as normal but because the tubes are not in the housing the fans in the back will run very slow.

Than I might just take the high tension cable and lead it through a hole in the attic straight down to the tubes. I might not even have to make that cable longer!

The other cables would go through there own hole as would be the best fit.

Now it might be necessarily to lengthen these cables but if not more than a meter I don't think that would add much resistance.

How about lengthening the high tension cable? If straight down through the attic I think I would use a metal shield around it but for the rest would this be possible? I do realize that 25kV should have enough safety and space.

This way I would really have split pack housing under the ceiling. I would use wood to make the frame. And I would need to work with a separate connector to be able to remove the unit.

Is this possible? The unit below the ceiling would be much smaller and I would not need a big hug box

HV wire!
http://www.ebay.nl/itm/Hochspannungskabel-40kV-1m-High-Voltage-Wire-/271261265512?pt=DE_Technik_Computerzubehör_Kabel_Adapter&hash=item3f286e6e68

[redfox001]

Thinking further on this idea I am convinced that it is possible to lengthen the HV cables with 30kV cables to be bought on ebay. There are also HV connectors available but Curt shows a dirty way of splicing a HV lead here:
http://www.curtpalme.com/HV_Lead_Splicing.shtm

I might not need this solution for myself because I might get a split pack beamer but I'm considering making these cables custom made for others. If I know more I will post on this forum.

Looking at the advanteges of a split CRT over modding the fans that is dangerous or building a hush boks that is not very pretty such a cable might be a nice solution What do you guys think? You might need a second housing for the tubes.

Connectors these?
http://www.ebay.com/itm/High-Voltage-Connector-30KV-DC-Plug-Socket-/151170260923?pt=LH_DefaultDomain_0&hash=item2332731fbb