CurtPalme.com Home Theater Forum

[cmjohnson]

I tested a bunch more tubes this evening. I found another blue with a tiny little spot right in the middle. It appears to be a shutdown burn, because when I shut this one down, I do get a little blue spot right about in the same spot. The spotkill circuit on the neck card IS working, it's only on this ONE tube that I see this shutdown spot. So I can presume that it's something actually wrong with the tube itself.

Fortunately it's made by Lexel, and Lexel is still in business so I may be able to get a warranty on it.

My current tally of good tested tubes with no issue is sufficient to fully retube four 9500LCs right now, and there will be more tubes
that will test perfect.

[the big E]

That's great that you can get the tube exchanged

I have been wanting a spare set of tubes for my 9501(just in case something goes south in the set)

If that is I don't decide to put together my other marquee chassis with fresh boards to do a blend or stack setup

[cmjohnson]

I won't know if it can be exchanged until I ask. I don't know the warranty terms. HOPING that it's exchangeable, of course.

[the big E]

I hope they do exchange it for you as that would surely be a defect in the tube

[cmjohnson]

I've now reached a total of seven tested, high quality sets of tubes with perfect phosphors.

Seven sets is NOT BAD!

I have found a couple that aren't PERFECT but their wear is so slight that I simply can't imagine that
nobody would want to buy them. It's the lightest wear pattern that I've ever actually SEEN. You'd miss it on casual inspection.

I'm assigning a grading system to them:

A+: A truly like new condition CRT with zero phosphor wear, like new performance, and needing only low range G2 and drive levels. A very sensitve, easy to drive tube that only is seen in the freshest, lowest hours tubes.

A: New condition, zero phosphor wear, new level performance, G2 and drive levels are typical of a tube that is still young but has
a couple hundred hours on it. A 10 on Curt's rating scale.

B: Highly sellable and usable, extremely faint wear that is difficult to see and easy to ignore. A 9 on Curt's rating scale.

C: Visible pattern wear that will be noticed from time to time. Still very usable but this is not the tube for a perfectionist. 8 on Curt's scale.

D: A usable tube with light but visible pattern wear OR "black spot" phosphor defects in the active raster area. 7 on Curt's scale.


E/F/G: I don't sell tubes in this quality range. But they may be usable for test purposes.
I left all those in the boxes when I was grabbing the best tubes.

[deronmoped]

So, price has always been a deciding factor in buying anything.

If people want minty stuff, they should be willing to pay up. Offer to build up the PJ's with whatever tubes they want and have a price for each.

Here is a though, use the worn tubes as a marketing ploy. Just like "Gray" screens were marketed for better blacks, the worn tubes are for better blacks. In fact, it's all relative. What a person perceives as white, is really a off-white. I mean, can anyone say they have seen a really pure white?

I wonder... Do worn tubes produce a better black image, you would think so.

[cmjohnson]

Thanks for the laugh!

For ultimate black levels, UNPLUG the projector!

Next I've got to get into all that LC hardware and set up at least a dozen units to be ready to receive tubes.

That includes cleaning, painting the parts that touch glycol with black VHT epoxy paint, changing out all the screws
for stainless hardware, inspecting the bellows, generally getting everything ready.

I kind of enjoy working with the CRTs themselves. Messing with the LC hardware is a bit more like work and a bit less like fun.

[the big E]

My ecp had a somewhat worn blue tube but I didn't mind as I knew at some point I would upgrade

Black levels didn't get effected by it color balance on top end of the grayscale yes

I have new tubes in my marquee so I have know how they do on full white
My dwin has a uneven wear pattern on the blue and it does effect the white balance in the set(doesn't matter as I have a second dwin also)

[cmjohnson]

That was kind of interesting. I was testing a few more tubes and suddenly had the horizontal winding on my test deflection yoke fail, and start arcing. Got a fairly bright light and loud buzz out of it. The projector shut down pretty quickly and nothing was damaged.

So I removed the damaged yoke, cut the leads off it, threw it away, while keeping the leads for experimental purposes, and then reached into my box of some 70-odd spare deflection yokes and continued the tests.

I've also found out, by trying it, that, no, you really can't attach the HV lead without siliconing it to the tube. It WILL arc to chassis ground.

I spent a few hours sorting and organizing my warehouse space to fit all this stuff into it. It's going to take a fair amount of shelf space to hold as many completed rebuilt LC assemblies as I think I'm going to end up with.

[the big E]

Wow that was a suprise

I don't think those could fail like that

Either end of the anode will arc(found that out when I was working on my ecp one night and had a anode feed disconnected from the hv block

Next thing I know I am hearing a snapping noise I look down to see the lead arcing to the set's ground(the smell of ozone stinks when close to the projector)


Good to know it didn't damage anything in the process

[cmjohnson]

Actually I siliconed the lead and let it cure overnight and attempted to start up the projector and it's not powering up to HV.

No fault lights.

Now it behaves exactly like the unit hanging in my HT room.

I'll have to do a few board swaps and find the problem. It's not the HVPS, I've already swapped in a known good spare.

[cmjohnson]

Projector's back up and running. Swapping out the HDM did the trick.

I didn't see that the HV arc contacted the deflection yoke but it may have taken enough of an induced pulse to damage the HDM.

I would hope not but now I have an HDM I can't trust until it's evaluated and properly repaired.

The H fail light did not appear on the CLM.

[the big E]

Could have been where the yoke failed that damaged the hdm

[cmjohnson]

Could be. I found damage on the anode lead cap. It was cut deeply when it was salvaged from a previous installation. It can be used again, but will require a generous application of silicone.

[cmjohnson]

I tested the final green to be tested out of this batch today. It tested perfect, just like a brand new tube. The total score of greens stands at eight perfect greens, one with light wear as seen on the first page of this topic, and one Thomas tube that's weak OR requires a 40KV HVPS.

[cmjohnson]

Make that SEVEN greens. One broke (insert very sad face) while attempting to warm it up to cure the Shin-Etsu silicone.

Shoulda tried it on a red first!

Oh well. Nothing to be done about it but clean up the mess.

And, this silicone is VERY, VERY messy indeed.

It's supposed to be cured in a large oven, at about 100 degrees C, for an hour. I now know that no, you can't do it over a stove,
no matter how gently you try to heat it, because you have to heat the whole thing evenly or thermal expansion differentials will break the tube.

So do I risk it? I know someone who has the right kind of oven. Or do I clean this ungodly mess out of seven more LC assemblies and start over with silicone that doesn't need heat curing?

Eventually the stuff I used WILL cure. But it might take several days at room temperature.

I made a mistake, and it cost me. That's life.

[cmjohnson]

A few samples of what I'm dealing with:

[cmjohnson]

I've still got a lot to do to get things better organized and more into the shelving. Space CAN be made!

[racerxnet]

Any tubes for the 8500 Marquee?

[the big E]