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Discussion Starter · #1 ·
I’ve finally got round to encapsulating the rear of my G70 and venting the hot / noisy exhaust through the wall and into the adjoining conservatory (which won’t notice the extra heat in summer and will benefit in winter – win/win).


Some pictures are attached (I had to crank the exposure on one of them in order to illustrate the importance of the extra part of the box which sits over the lvps exhaust – specifically the FA/FAA/FAB boards). I’ve had two FAB board faults in two different G70’s and I think this is due to insufficient ventilation in the stock G70. I guess I’ll find out.



I have a total of 510 CM/H fans on the two exhausts (1 x 350 and 1 x 160) this has reduced the internal temperatures significantly. I’ve put probes inside the G70 and at the exhaust grilles and temperatures have reduced from the high twenties / low thirties by about 6 degrees C. Standby temperatures appear to be unchanged despite being totally enclosed and the fans being off.


As you’ll see from the pictures I have a bespoke metal box made by a local engineering company and had that and the G70 plastics sprayed satin black, which in my opinion is preferable to the Sony corporate greys. The two rear plates were removed and the power socket and switch relocated to the new box.


I’ve yet to make up an elongated “u” section to cover the silver exhausts and cables, but I’ll get around to that soon-ish.
– This should further reduce noise.


The temperature probes are actually fish tank probes, currently dangling from a gap near the hinge (handy to get the cable out of the case).




 

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I am finding this totally depressing. I have been sitting with a 1270 or a 1271 for the last seven years and never had a day of trouble with either. And never had to entertain the idea of hooking up cocakamamie** vent pipes and inserting temperature probes to keep them from imploding. Now of course I am looking forward to the weekend taking this G70 all apart just to get my first real taste of it. And then Dragan who has been amazing with the help has sort of spooked me into expecting a short lifespan with this projector.


And one of the things I have been sort of liking about this projector, in the couple hours I had it on it seemed no louder than the 1200s and thought it was nice there were no downfiring vents which is nice for the people under the projy, maybe not as nice for those in the new rear seats.


Seems like everyone has G70s though. I don't know what to think anymore.

Just crossing my fingers and hoping for some luck I guess. But now I am contemplating sending the most notorious boards in to have them modded for

durability. It always sounds like Curt is working up there in the North Pole like Santa just taking in little boxes of boards, sprinkling fairy dust on them and sending them back home to their owners like its no big deal. I guess the strategy is to wait for one to blow then send them all. Or is it better to do this while its still on the floor? Or am I just scaring myself needlessly?


**No offense intended on the vents. Its just, you all are frightening me and the day I bought it I was sooooo happy. I buy something I don't expect to have to duct tape hoses to it to keep it alive.
 

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Discussion Starter · #6 ·
Don’t panic atomiccow… I did this venting job for these reasons:


1. Sony say a 12” gap behind the projector is the minimum required for proper cooling. My space is a little short of that.

2. The PJ is on the ceiling – the hottest part of the room and although I use aircon in the HT in the summer, I do enjoy a fire in the winter (stove, so not too much light into the room) and the temperature at ceiling height can get quite hot (for the UK that is).

3. An attempt to quiet the wee beastie although I could live with it stock - I sit directly underneath with a wall almost immediately behind (~18”)

4. To deliberately over engineer the cooling to extend the life of the PJ.

5. To hide all the cables etc. and remove the copious quantities of hot air generated by the G70 from the HT.


Naturally all this comes at a price: I need to check the temperature probes and fans from time to time and the several hundred bucks I’m out of pocket for the construction.


Curt will perhaps comment on the FAB failures I had (two little resistors zapped (presumably due to a power tranny going pop)). Could this be down to the relatively slow air movement past the FA boards?
 

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I think the G70 problems can all be traced back to cooling problems. On a Marquee or Barco you have coooling fans close to the outside of the machine pulling in cool air and blowing it over the boards. On a G70, the fans are in the middle of the machine, in between the tubes and card cages.

I believe they draw air in over the cards and blow it onto the tubes and a little goes into the E and DC card cages but by this time that air is already warm and it's ability to cool diminished.

The other big problem with the G70 is very extensive use of SMT construction. the ability of these parts to shed heat is much less than the larger through-hole components, especially when you bury them in a hot chassis. IT's why the DC an E boards go out.
 

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Quote:
Originally Posted by WTS /forum/post/16908520


Actually most of the Barcos suck air across the boards and then exhausts, except for the conv tray which blows air into the tray.

Ah, thanks for clarifying. at any rate Barco's run forever with few problems. They also didn't put any un-cooled boards between the tubes like on the G70.

I think on the late model G70's,just before they quit making them, they tried to put a little fan on the DC (convergence) board but once again it has no access to cool air from outside the machine. those sony engineers really outsmarted themselves on this one.

Quote:
Originally Posted by atomiccow /forum/post/16906238


Now of course I am looking forward to the weekend taking this G70 all apart just to get my first real taste of it. And then Dragan who has been amazing with the help has sort of spooked me into expecting a short lifespan with this projector.

I sure hope you are successful, that box weighed 133 pounds I think? That was with no tubes, DC, E, B, YA-YB boards, or plastic cover. Fedex guy is loving you right now
 

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Dragan, why do you keep doing this to people? Why does it seem to be your personal mission to make sure everybody knows the G70 sucks? Time and time again, whenever somebody brings up the G70, you go on and on about how bad they are reliability-wise and/or how bad the design is.


Then, in several of the threads where you crapped on the G70, I've re-stated Curt's opinion that there are no appreciable reliability differences between most machines (save for a few specific weak points... G70 PA board or Marquee LVPS, for instance). Then, you say nothing and the thread dies.


Let me state that again for everybody else's benefit: Our favorite CRT repair tech, well-known in the industry for his experience and wealth of knowledge of all things relating to CRT repair, Curt Palme, has stated the following on several occasions: While there may be a specific weak point (or points) in almost every projector design, there are no appreciable reliability differences between most of these machines, whether they be Barco, NEC, Electrohome, or Sony.

Quote:
Originally Posted by draganm /forum/post/0


They also didn't put any un-cooled boards between the tubes like on the G70.

WTF are you talking about? Yes, the fans are in the middle of the chassis - but, so what? Your air handler is in the middle of your house, and it heats and cools just fine. The fresh, cool air is drawn in around the lenses at the front of the chassis, flows through the CRT assembly, through the big fans, through the card cage at the back of the machine, and out the exhaust at the rear. It seems to work fine to me.


The PA board is about the only board that doesn't see any air flow. While it's by far the most common G70 failure, it's usually when somebody has some massive geometry adjustments railing on the deflection. Regardless, like everything else, you send it to Curt, he repairs it, and sends it back. Big whoop.


Atomiccow, don't let dragan scare you. There are a whole slew of us here and on Curt's forum that are all running G70's with no problems... many at 1080p. If you look outside Dragan's Marquee Reality Distortion Field, you'll see there are just as many posts from people with busted Marquees, NEC's, and Barcos as there are with busted G70's.


They all break, they can all be fixed...


SC
 

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Quote:
Originally Posted by ecrabb /forum/post/16909672


Dragan, why do you keep doing this to people? Why does it seem to be your personal mission to make sure everybody knows the G70 sucks? Time and time again, SC

errrr, because they suck. I know more about the G70 than you do. I've worked on a quite a few. You just bought a low hour one and stuck it on the ceiling. for one thing, the fans pull from the back and blow forward, taking hot air from the power supply boards and then trying to cool the DC and E-boards with it.

Quote:
Originally Posted by Curt Palme /forum/post/16859806


Keep in mind though that I've only seen heat related failures of G70s in about the last 2-3 months. That mod has been up for over a year. That's the problem with mods. Without significant R&D, you can't determine whether some aftermarket mod will have long term effects on a set. I know the fan mod on the NEC PG I took apart worked fine, in fact I marvelled at the quietness of the unit when I fired it up.. before I saw the PC board with the regulator on it. As soon as I pulled out the F and C boards, I saw the long term damage that the lack of airflow did.
What I'm seeing now is that even the stock fans don't seem to be doing a good job on areas in the G70. I will put up a disclaimer specifically on the Sony fan mod though.

Basically, even though it's already loud to begin with you really want to add MORe fans to a g70, not reduce the air-flow in any way.
 

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Sniff..


Everyone know's NECs are the most reliable.



But it's always seemed to me that Marquees have the biggest issues (filament voltage/LVPS stuff), followed by Barco Quads. LOL.
 

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Quote:
Originally Posted by draganm /forum/post/16907866


On a G70, the fans are in the middle of the machine, in between the tubes and card cages.

I believe they draw air in over the cards and blow it onto the tubes and a little goes into the E and DC card cages but by this time that air is already warm and it's ability to cool diminished.

In the for what its worth department air is actually pulled in from around the lenes/tubes and blown out the card cages. One fan for the red tube and F&G boards, one for the Green tube and E boards, and one for the blue tube and Y&B boards.

Quote:
Originally Posted by draganm /forum/post/16907866


On a G70, the fans are in the middle of the machine, in between the tubes and card cages.

Uppp, So! I believe this was an attempt to bury the noise of the high static pressure fans deep in the PJ to help reduce noise.


Quote:
Originally Posted by draganm /forum/post/16907866


IT's why the DC an E boards go out.

Not my experience. Going on 8 years and have only had 2 PA boards issues that were easily fixed by Curt


Quote:
Originally Posted by draganm /forum/post/16907866


I think the G70 problems can all be traced back to cooling problems.

I disagree. My belief is that people who post with chronic PJ problems unfortunately got their hands on a machine that was already tinkered with by someone who had no business under the hood.
 

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Quote:
Originally Posted by draganm /forum/post/16910272


I know more about the G70 than you do. I've worked on a quite a few.


...for one thing, the fans pull from the back and blow forward, taking hot air from the power supply boards and then trying to cool the DC and E-boards with it.
Are you sure your talking about a G70? That statement is completely wrong.
 

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Quote:
Originally Posted by AFryia /forum/post/16910476

Are you sure your talking about a G70? That statement is completely wrong.

Heh,


I was going to say the same thing, he must have had some special G70's, the fans in mine go the other way.


And FWIW my G70 has almost 8k hours of "my use" and has only had one problem the entire time I've owned it, sent some boards to Curt and all is well now, and has been for the past 3k hours. My G70 is also exposed to extreme conditions from sub zero tempertures to heat waves over 100 degrees.


I bet Draganm's just jealous, we get better tubes, better lenses, stock color filtering, LC, and a better case from the get go.
 

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Quote:
Originally Posted by AFryia /forum/post/16910476

Are you sure your talking about a G70? That statement is completely wrong.

it's been over a year since I fired up one of those loud ass clunkers. The point is that with the fans in the middle of the PJ it doesn't matter which way they blow. It's either taking the heat off the deflection coils and DC board and blowing it over the card cages or taking the hot air from the card cages and trying to cool the DC an E with it.

you don't have to take my word for it, I'll re-post this for anyone who missed it

Quote:
Quote:
Originally Posted by Curt Palme

Keep in mind though that I've only seen heat related failures of G70s in about the last 2-3 months. What I'm seeing now is that even the stock fans don't seem to be doing a good job on areas in the G70.
Quote:
Originally Posted by Fellenz /forum/post/16910538


I bet Draganm's just jealous, we get better tubes, better lenses, stock color filtering, LC, and a better case from the get go.


compared to a plain 8500 yes, they have a perfromance advantage but only when they're running. I'm currently working on a 9500Lc though so not feeling all that "jealous" really.


Look I just gave away a G70 chassis with the PA board for $25., the only reason I stored it at all is to help all the unfortunate sony guys out there.
 

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Quote:
Originally Posted by barcoed /forum/post/16906359


Don't panic atomiccow I did this venting job for these reasons:


1. Sony say a 12 gap behind the projector is the minimum required for proper cooling. My space is a little short of that.

2. The PJ is on the ceiling - the hottest part of the room and although I use aircon in the HT in the summer, I do enjoy a fire in the winter (stove, so not too much light into the room) and the temperature at ceiling height can get quite hot (for the UK that is).

3. An attempt to quiet the wee beastie although I could live with it stock - I sit directly underneath with a wall almost immediately behind (~18)

4. To deliberately over engineer the cooling to extend the life of the PJ.

5. To hide all the cables etc. and remove the copious quantities of hot air generated by the G70 from the HT.


Naturally all this comes at a price: I need to check the temperature probes and fans from time to time and the several hundred bucks I'm out of pocket for the construction.


Curt will perhaps comment on the FAB failures I had (two little resistors zapped (presumably due to a power tranny going pop)). Could this be down to the relatively slow air movement past the FA boards?

Thanks for the reassurance. I have several feet behind my projector. I am trying to keep an good face on it but am anxious about my success with this major transfer of tubes and components I am facing in as soon as a day or two. I get bummed easily right now.
 

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Quote:
Originally Posted by draganm /forum/post/16908876


Ah, thanks for clarifying. at any rate Barco's run forever with few problems. They also didn't put any un-cooled boards between the tubes like on the G70.

I think on the late model G70's,just before they quit making them, they tried to put a little fan on the DC (convergence) board but once again it has no access to cool air from outside the machine. those sony engineers really outsmarted themselves on this one.


I sure hope you are successful, that box weighed 133 pounds I think? That was with no tubes, DC, E, B, YA-YB boards, or plastic cover. Fedex guy is loving you right now

120 pounds for future reference.
I'm was a little scared about the bill when I say it was twenty two pounds over the guesstimate. But I checked my account and have more money in there than I thought. I was just reading tonight about your fabulous Marquee mods. Every day I am finding out more and more what a projector god I have been dealing with. Thanks again. I so far have not had to pack a projector, and its enough of an ordeal just trying to get one here. I did not take your packing for granted. I paid more in guilt than in cash. (BTW I tried to send as gift so I would pay the dollar fee. The only way we could make it go through is as a sale.)


People shipping projectors should look into Pilot Air especially if they can pick them up near the airport terminal. Very cheap.
 

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Quote:
Originally Posted by atomiccow /forum/post/16911933


I was just reading tonight about your fabulous Marquee mods. Every day I am finding out more and more what a projector god I have been dealing with. Thanks again.

Oh stop, your embarrasing me. i'm a very modest person even though everyone here will likely say "arrogant ass"


the swap is pretty easy, the G70 isn't laid out badly AFA assembly is concerned. One little tip I can remember is slide the tubes out 2 or 3 inches before trying to re-move or re-install the video neck-board onto the pin-outs. there's very little room back there, so a few extra inches makes a big difference. don't force it or you will bend a pin on the tube. It should slide on without too much trouble.
 
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