CurtPalme.com Home Theater Forum

[Curt Palme]

OK, maybe it's a fluke, but I've had two NEC XGs crack tubes in the last month. I'd seen this three times before, but this may be more common now that the sets are getting older.

Heck, I'll even tell you what the problem is exactly.

The V chip on the V board fails, and shoots the electron beam way off the tube face. The electron stream ends up hitting the tube neck where the bell of the tube flares out, and that super heats the glass.. and the tube cracks.

For some reason, the chassis doesn't register the 'way off' V deflection as an error, and the set keeps running.

I had another locally sold set do this yesterday, and now I'm concerned for other XG owners out there.

I'm going to put this on the next emailer that goes out as well, but beware.

I will be offering discounted repairs, as the chips on the XG boards are not the easiest to get off the board, and if you don't have decent soldering skills, you can kill the board.

I'll offer board swaps with new chips installed or the repair of your V board for $100 incl return shipping within the US, $125 overseas.

Anyways, just FYI, I want to see the XGs on ceilings, not in junk piles.\

This flaw affects all models, LC and non LC.

[Curt Palme]

OK, maybe it's a fluke, but I've had two NEC XGs crack tubes in the last month. I'd seen this three times before, but this may be more common now that the sets are getting older.

Heck, I'll even tell you what the problem is exactly.

The V chip on the V board fails, and shoots the electron beam way off the tube face. The electron stream ends up hitting the tube neck where the bell of the tube flares out, and that super heats the glass.. and the tube cracks.

For some reason, the chassis doesn't register the 'way off' V deflection as an error, and the set keeps running.

I had another locally sold set do this yesterday, and now I'm concerned for other XG owners out there.

I'm going to put this on the next emailer that goes out as well, but beware.

I will be offering discounted repairs, as the chips on the XG boards are not the easiest to get off the board, and if you don't have decent soldering skills, you can kill the board.

I'll offer board swaps with new chips installed or the repair of your V board for $100 incl return shipping within the US, $125 overseas.

Anyways, just FYI, I want to see the XGs on ceilings, not in junk piles.\

This flaw affects all models, LC and non LC.

[dvh99]

if they are surface mount use chipquick it is the easiest way for removing surface mount ic`s.
guaranteed zero damage to the boards.
putting the chip back on is easy done with solder paste and a hot air gun moderate air flow and 390 degrees celsius.
http://www.youtube.com/watch?v=FTQqjggeklo

[draganm]

[jarseneau]

Yikes! I think I had a form of this problem a while back where intermittently I could have a bright glow off to the side when looking at the RED CRT face. Didn't crack anything but I bet it would have if not caught in time. At the time the problem was fixed with another V drive board.

[Boilermaker]

Double Yikes!!

Is there any warning of this - Anything I can be looking for?


Bob

[Curt Palme]

Nope, that's why I posted it and am offering discounted repair rates on rebuilding the V board.

Once the V section fails, you have less than 30 seconds to turn the set off to save the tube(s). It happened right in front of me a few years ago, the green image would drop out, and in trying to repair the set, I had to have it on... POP, the green tube neck snapped.

[Curt Palme]

Nope, that's why I posted it and am offering discounted repair rates on rebuilding the V board.

Once the V section fails, you have less than 30 seconds to turn the set off to save the tube(s). It happened right in front of me a few years ago, the green image would drop out, and in trying to repair the set, I had to have it on... POP, the green tube neck snapped.

[Jeremy112]

Ill have to look at the layout page to see where the V board is on the projector (I've not gotten much into the internals on the projector yet) and then do this mod. The last thing I need is a cracked tube in my "new" projector!

Thanks curt

[Boilermaker]

I need to send one to you anyway, so I'l just include this.

Thanks,
Bob

[dvh99]

if i would own a nec i would do it anyway even if it is still working fine.
better safe then sorry.

[Jeremy112]

[jarseneau]

[Das444]

Curt,
Do the units all have about the same hours when the V-chip fails? And is it the same tube all the time (green). Will this guarantee that it will not happen or more of insurance ?

Thanks,
Dan

[Jeremy112]

I assume the V-board that is being discussed is a the V output/H shift board I see in the Tips and Manuals layout page? And would it br wrong to ask what the # of the chip is?

[RogerH]

Curt

I'm confused. Are you offering repair of already-defective boards, replacement of the STK amp as an insurance measure on working boards, or some other mod to enhance the swing detect circuit that is already there (and apparently not catching everything)?

[Curt Palme]

I have not kept track of hour count. NEC had some sets with really bad heatsinking compound that would dry up and cause the chips to overheat prematurely, then I guess they caught it, as a bunch of other XGs I've seen recently have nice and pliable/sticky compound.

Roger, I only offer a repair to put in new chips to prevent the problem from happening for another 10 or so years, I haven't researched (nor will I) as to a fix for the error detection.

[Curt Palme]

I have not kept track of hour count. NEC had some sets with really bad heatsinking compound that would dry up and cause the chips to overheat prematurely, then I guess they caught it, as a bunch of other XGs I've seen recently have nice and pliable/sticky compound.

Roger, I only offer a repair to put in new chips to prevent the problem from happening for another 10 or so years, I haven't researched (nor will I) as to a fix for the error detection.

[jarseneau]

Can I assume that if I already replaced the V-drive STK's that there's no reason to send the board in for this update?

[Jeremy112]

So it's the STK Chips at the bottom on the heatsink that are the cause?

[Curt Palme]

That's part of it.

[Curt Palme]

That's part of it.

[Curt Palme]

Well, the day is turning into a wash. I replaced the tube and V chips in the customer's set, it ran fine all weekend. Took it back today. Powers up, shuts off with an Fc code. Powered up again, it works fine. Strange.

I'm tightening the ceiling bracket hardware while eyevballing the 'Oppo' logo on the screen, and I see the blue image collapse and shoot to the top of the image. I shut the set off quickly (pulled the power cord), and powered up again. Same Fc error. Damn!

So either I didn't repair the V board incorrectly, a chip went bad (very unlikely), or there's something else in the blue V drive that's bad.

I'll stick to my guns as to the V board issue on these XGs as originally posted, but in this set there's something else awry. I'll update soon.

[Curt Palme]

Well, the day is turning into a wash. I replaced the tube and V chips in the customer's set, it ran fine all weekend. Took it back today. Powers up, shuts off with an Fc code. Powered up again, it works fine. Strange.

I'm tightening the ceiling bracket hardware while eyevballing the 'Oppo' logo on the screen, and I see the blue image collapse and shoot to the top of the image. I shut the set off quickly (pulled the power cord), and powered up again. Same Fc error. Damn!

So either I didn't repair the V board incorrectly, a chip went bad (very unlikely), or there's something else in the blue V drive that's bad.

I'll stick to my guns as to the V board issue on these XGs as originally posted, but in this set there's something else awry. I'll update soon.

[Jeremy112]

well perhaps when you finally get the issue figured out for sure, and depending on how extensive the repair is, I may just send you my V-board, I'm not in a rush as I'm still gathering accessories for the XG anyway sucha s the DVI card and some new plastics to make her puurrrty