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Discussion Starter · #1 ·
The history

I bought a sweet minty G70 last month but unfortunately my sweet but dopey seller loosened glycol into the projector. After cleaning what little glycol I could find, the projector worked for two hours before developing a short in the motherboard. Unfortunately this means pulling almost everything out for removal.


The goal


This is the story of doing a motherboard replacement. Apparently even Curt Palme has not even done a motherboard replacement on a G70. When I am done I'll try to give a summary of what I had to do. Maybe skip over how to remove tubes. Its been done at least a couple times.

The cancelled transplant

Dragan sent me a chassis with a motherboard. And the plan was to take out my parts and put them in his chassis to keep things simpler. But after looking at both projectors for a couple hours I could see they were not exactly the same. There were about five minor differences. One was an additional plugin on the PA board and I remember Curt saying the PA board tends to need to be tuned to the components of the specific projector. Also complicating things there were some detached and missing wires and about six or more major boards needed moving. Last, my projector is black/dark gray. Removing the light gray panels off the base and replacing them with the dark gray is almost harder than removing anything else on the projector.


The risk.


By keeping my original chassis there is the risk of lingering glycol in hidden areas causing a problem later.

But everything about my original projector chassis has the extra sheen and sparkle of virgin newness like its been sitting in a box unopened.


I took lots of pictures. I may try to post my steps in picture form later.
 

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Quote:
Originally Posted by atomiccow /forum/post/16944369


Do I need to unscrew anything or just yank? But I am nervous about pulling too hard.

you need to unscrew the screw in the picture, notice it's part of a clamp.


The chassis I sent you has the matching PA board and all the DC power boards in it.

simply swap tubes, YA-YB, B, E, and DC. should take you like 30 minutes.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by draganm /forum/post/16944686


you need to unscrew the screw in the picture, notice it's part of a clamp.


The chassis I sent you has the matching PA board and all the DC power boards in it.

simply swap tubes, YA-YB, B, E, and DC. should take you like 30 minutes.

Thanks for the help.


30 minutes is easy for you to say! Its my first time.


I spent over an hour just taking photos. Longer than that just looking it over.


True I could pop in the boards pretty fast. but it seemed safer and faster in the long run to keep what I had. The PA board on mine and yours is a little different. Mine has an additional wire harness and clip yours didn't have. I'll show you pictures later. If it fails I'll change PA boards. But Curt makes a comment in his instructions on the PA board that you can't necessarily just change PA boards on a G70 willy nilly.


The chassis was great, but somehow mine looks more sparkly and brand new. The metal shines and the plastic on the wires glistens. Its the difference between a clean car that has been owned for a year or two and a brand new never driven car. I guess its dumb it factored in. I'll probably never see the insides again. But somehow I want to be driving the new car.




But what your chassis did for me is gave me a lot of confidence in taking it apart. I could practice and compare. Once I got those big gray sleeves off your chassis the whole project looked far less intimidating. I still have to remove the blue tube and change motherboards then I will be putting stuff back together.


***********


Your reputation for great packing is certainly in tact. It looks like you pour your own urethane foam and make custom shapes in garbage baggies? Pretty wild. Your thinning of the box was well done as well.

There is still a possibility I will get refunded for the whole delivery.
 

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Discussion Starter · #4 ·
Okay I am stuck.

Does anyone know how to remove/decouple these joining clips? It would be a help if I even knew what they were called.




If I can't get them unjoined, it looks like I'll be forced to swap cases after all.
 

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You mean the multi-pin connectors?


You need to remove all the screws from the board first. They are usually the gold colored Philips heads. you can see one in your picture.
 

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Quote:
Originally Posted by atomiccow /forum/post/16945244


There is still a possibility I will get refunded for the whole delivery.

why did they rough up the box? Fedex ground has been very, very good but they do struggle with stuff over 100 pounds. I thnik they're just not set-up to handle those heavy things.
 

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Once the board is loose, it will simply slide out and the connectors will separate.
 

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Quote:
Originally Posted by atomiccow /forum/post/16945244


But what your chassis did for me is gave me a lot of confidence in taking it apart. I could practice and compare. Once I got those big gray sleeves off your chassis the whole project looked far less intimidating. I still have to remove the blue tube and change motherboards then I will be putting stuff back together..

well that confidence is your best ally, I think taking your time is a good way to go. If you can simply swap MB's then do that. IT will be interstign to see if there's any Glycol underneath your old one?
 

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Discussion Starter · #9 ·
Hmmm. All the screws were out. The picture of the connector is from before I took em out. I just woke up I'll go give it another tug. I tend to be tentative about applying pressure at this point. Crossing my fingers everything will be running again tonight.
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by draganm /forum/post/16947445


well that confidence is your best ally, I think taking your time is a good way to go. If you can simply swap MB's then do that. IT will be interstign to see if there's any Glycol underneath your old one?

Its actually my concern there is no glycol. I don't see it anywhere else. I have only found it in strange places like small bits of aerosol on the little MT board. And oddly in the back of the exterior of the chassis. But it definitely lost 2-3 ounces which is actually quite a lot for it to just disappear. It doesn't clean easy. So "where is the glycol?" is a mystery. But a bigger and more disturbing mystery is would be not knowing why the board shorted.


Fed Ex promised me Thursday or Friday delivery and I am holding them to it. I set aside the weekend and had to make calls all week to get it here after it left Denver and then wound up back in Brighton. I got it Monday a week after I phoned it in. I could have used Pilot Air and got it here Wednesday or UPS and got it Monday forty bucks cheaper.


I hate having to do this project but what a way to get familiar with your projector to literally take it all apart, see the boards, learn what they are a little, and know I'll never have a harder job for the rest of its life than what I just did...knock wood.
 

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Discussion Starter · #11 ·
The motherboard is out and she earned her name. She was a mother to get out.

When this is over I will try to diagram how I got it out.


But if I were to give advice. I would say don't do it. They made it about as difficult to remove as possible. Its pinned on three sides with those large DIN connectors. And partially pinned on the 4th side by the MT board. Even if you have all the tubes and other cards out of the way for clearance you aren't done removing cards. You have to loosen the PA board, remove the big board on the red tube side to gain access to the screws on the DM board. The worst is one screw is almost inaccessible without a really long thin phillips screwdriver,which fortunately I had. Then after struggling with the DIN clips and trying to get it off all the little dark gray board risers it still fought me like a *****. Then finally giving itself up after mysteriously requiring a long lateral slide where it felt like it was in a track...which it wasn't. I'm still scratching my head over that. I was forced to pull down half of a protective rubber "L" moulding to get some clearance. By that time that was done, any incentive on pretense to stay in this chassis because it was "sparkly new" seemed now irrelevant. I am just going to move everything over the Dragan chassis.


It would have been easier to do that in the first place. But I had to know why it shorted. It would have nagged at me.
 

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Discussion Starter · #12 ·
Hey finally some fun. Everyone likes seeing pictures of other people's misfortune.

Here's a chance to enjoy viewing my personal burn.



Maybe some of you pros can even tell what happened before I put this all back together.


Here is the burn. But no glycol to be found here or anywhere else in the projector.



And here is where the short occured. This is on the back of the motherboard on the blue tube side.


I am very curious about the gooey pill shaped blob that turned into a smudge when I put my finger on it.



Here is where is corresponds to the other side.


I could see the board glow green here from underneath when I turned it on. I probably saw it pop about five times before I stopped trying to turn it on again.


Here is a picture of Cordelia from "Angel" and Buffy the Vampire Slayer.

It doesn't have anything to do with diagnosing the problem. But thought it might get your attention.



Because my next picture is just a very thin layer of something not sexy. It was damp in the dust beneath the blue tube. Could this be glycol? Could this have shorted my board. I am not smart enough to know. But there may be someone smart enough here who can say!


Its eleven inches from the short. But on the back side, following the labyrinth of circuits, the path gets fairly close to the trouble zone. But I don't know if what's on the front affects the back.
 

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Discussion Starter · #13 ·
I am trying to have some fun with my problem.

But I would like to know if anything I have shown is "revealing".


Getting back the the first time the projector shut down, I got an error code indicating a "Fan" problem and then I turned it on and got the "POP" sound inside and an error code "LOT" which translates to being an extraordinary load on the PA board. Turned it on again and saw it pop and glow beneath the circuit board. It actually recovered and ran for ten minutes, then fan code, then LOT code.


And then the rest is what you see in the pictures.


I am going to go put it all back together tonight if I can. I have been stalling all day. I am guessing its because I don't want to put it all together and experience it not working. Again I'll just have to man up.
 

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Its hard to tell without seeing the Mother Board in real life but in My opinion its more than likely Optical Glycol is what caused your shorting.. please remember that this stuff is Extreamly corrosive and will continue to be untill completely removed ...


Damage/shorting of other boards may accur if the issue is not rectified completely as I pointed out when you first bought the G70...


Cheers....
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by cinema mad /forum/post/16952340


Its hard to tell without seeing the Mother Board in real life but in My opinion its more than likely Optical Glycol is what caused your shorting.. please remember that this stuff is Extreamly corrosive and will continue to be untill completely removed ...


Damage/shorting of other boards may accur if the issue is not rectified completely as I pointed out when you first bought the G70...


Cheers....

Thanks.

I will be using another motherboard and case. Since I have taken almost every board out of the projector, the only place I see any remnants of the glycol are on that one just found spot on the top of that motherboard. I saw some very mild aerosol droplets on the MT board which I cleaned very thoroughly the day I got it back. I listened to everyone's advice. Especially the guy who told me to take tons of pictures and write notes and diagrams.


I will probably continue to use most of my existing boards and put them in the new chassis. They were all shielded or far away from any glycol.

The MT board might be the one exception. Its very easy to swap out if necessary.
 

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hard to say, you would haver to trace the 180V line through the chassis but it's likely that since the leak was on blue that stuff migrated into the high voltage transformer. This could have caused the short on the MB
 

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try taking out the HV transformer in the old chassis, see what you find?
 

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Did the chassis from Dragan have tubes?


If so, make sure you fit the crappy tubes when you fire up whichever chassis you go with.
 

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Quote:
Originally Posted by atomiccow /forum/post/16949864


The motherboard is out and she earned her name. She was a mother to get out.

When this is over I will try to diagram how I got it out.


But if I were to give advice. I would say don't do it. They made it about as difficult to remove as possible. Its pinned on three sides with those large DIN connectors. And partially pinned on the 4th side by the MT board.

I could have saved you some trouble. With the PJ sitting table top remove the left side aluminum cover(red tube side). This allows removal of the D board 'L' connector and daughter board. This will give you more room to maneuver the MB board.
 

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Quote:
Originally Posted by Mark_A_W /forum/post/16956462


Did the chassis from Dragan have tubes?

If so, make sure you fit the crappy tubes when you fire up whichever chassis you go with.

that's a very good suggestion Mark, unfortunately I didn't have any complete tubes. I sold all the c-elements and LC chambers. This was a working chassis though with no problems.
 
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