CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm checking out the G90 I got today and as expected, the blue tube is broken, not in two pieces but
the glass is cracked and phosphor is missing off the CRT face.

I do not wish to damage the anode lead or anode connector but it's not moving. I'v tried pushing and twisting, both ways,
and pulling and twisting, both ways, and it's not coming out of the HV splitter block.

I know there's a trick to it. But I don't seem to know the trick at this exact moment.

If you know the trick to removing anode leads from Sony CRT projectors like the G90, please let me know

I can't really replace this tube without getting the old one out first.

**Curt Palme** · Posted: Mon Oct 03, 2016 1:22 am Post subject:

Pull back rubber boot
Push down hard on red wire.
Twist red wire CCW about 90 degrees.

If you did it right, the lead will pop right out. If not, repeat.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Of course that was right. I simply hadn't pulled the boot back far enough.

The blue tube assembly is out and I'll tear apart the assembly and get the tube out tomorrow. I have had a very long day
with over 400 miles of driving in it. Time to call it a day.

First impressions of the inside of a G90 in person: It has the look of the engineering of a Sony Trinitron from the best days
of Sony. Only more so. Very neat, very clean, very orderly...VERY COMPLEX, TOO.

The designers of the chassis and hardware probably cost Sony for their engineering on the G90 as much as the designers of the circuits did.

Its design and layout is quintessentially Japanese.

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

There's a certain way that the Japanese tend to design and build high quality electronics. It's many details and difficult to define,
but believe me, it's a compliment! Compare it to, for example, Russian engineering, which is as simple as it can be and still
achieve the basic goal.

The Japanese method is about quality and attention to detail. And while it tends to be rather mechanically complex and labor
intensive to build, it's robust. It's not going to deteriorate much over the next few decades.

I've been playing with and repairing and exploring electronics for about 40 years now. I've been inside so many various pieces
of audio and video equipment that I can look at the way a unit is made, one I've never seen before, and without knowing the brand
I can tell you, with a high degree of certainty, what company made it and where it was made. And when.

This is especially true of products made prior to the year 2000. In the early 2000s things started getting more generic,
probably because most of them were being made in the same factories in China.

The Japanese made stuff is made neater, cleaner, more elegantly. It's manufacturing art. And I love to work with stuff like this.

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

Ah cool, thanks for clarifying. Don't worry - I wasn't assuming you were being crass. Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

You were assuming it was an insulting comment. Which frankly I don't understand.

Japanese workmanship and quality is first rate and it has been so for a thousand years or more.

One thing I do is collect what few Japanese swords I am able to afford to buy. None are amazing pieces worth a lot of
money but even the most ordinary of these swords, a simple piece of metal, to the eyes of most people, is a beautiful
example of the work of Japanese swordsmiths and sword polishers, people whose skills are so developed that even the
lowest ranked of them completely outclass all but the best American and European bladesmiths.

Every craftsman should strive to do work that is good enough to be compared to Japanese work.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

OK, next question: What is the preferred method of removing the CRT from the frame it is siliconed into?

I'm guessing...razor blade into the gap from the face side?

Marquee tubes I can handle. They require a lot of silicone digging and the last phase involves pressing the CRT out
of the frame, usually.

But with the G90 tube in the frame, I'd rather ask an expert who may know a trick that will be very helpful and save me a lot of time and effort.

hal · Joined: 28 Nov 2012 Posts: 100

There might be a few tips in this?

http://www.curtpalme.com/Sony_G90_tube_replacement1.shtm

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I knew that was here somewhere. Thanks!

The green tube is worn and will be replaced, too. I will probably do the red as well, why not?
I have an over-abundance of red tubes!

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I found a slightly improved method to remove the CRT from the frame.

Single edge razor blades are cheap. So buy a box of 100 of them.

Insert as many of them as you can, around the rim, between the CRT and the frame, as long as you don't try to stack
them on top of each other. To cut the corner silicone, remove the metal back and use a plastic block or something to push the blade around. Stick the blades into the silicone as far as you can and you'll feel them push completely through the silicone just before most of them bottom out against their backs. When you've stuck about eight or so blades in and you've got bare blades buried in the corners, you will be able to pry the frame off with minimal force.

It's fast, easy, and rather safe, especially if you only use a block to push the blades into the silicone, and not your fingers.

Don't lose the four steel locator pins!

**Curt Palme** · Posted: Mon Oct 03, 2016 1:41 pm Post subject:

Those locator pins keep the tube off the steel, and from what I understand, allow tube glass to expand and contract as it heats up. If you lose one (I did the other day), a small laptop screw (super short) drops right in, and is about the same height as the spacers. Works like a charm!

garyfritz · Joined: 08 Apr 2006 Posts: 12026 Location: Fort Collins, CO

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I recovered all four pins, and the broken tube is out, the chamber is cleaned, and I'll be putting a new tube in it this morning.

The silicone I use does not require weeks to cure as the guide suggests. Silicone today, run the PJ tomorrow.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I've got a blue tube siliconed into the housing, now I wait for it to cure.

The tube is not perfect, it has a wear mark on the phosphor, but considering I haven't even powered up this projector yet,
I am unwilling to risk a perfect tube on an untested projector that MIGHT spot burn the tube.

When it's proven working then I'll put new tubes into it.

I'm impressed at the serviceability of the G90 chassis. It's a very well thought out layout.

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Yes, he did. By reviewing his photos that's when I knew the blue tube would be physically broken (it's not in pieces, but cracked all the way through and it has some glycol cooling the electron gun assembly) and that it would include a Moome HDMI input card, a very welcome addition!

I'll be installing the replacement blue tube in the morning. Then time to power the beast up!

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Fortunately I was paying attention. I don't have to redo any work.

One thing that's interesting about the G90 is that the tubes are not all oriented in the same position.

This makes it very important to take careful note of proper tube orientation when the tubes are installed in the LC assembly.

Frankly this is the only thing yet I've seen about the G90 that makes me think "Dumb engineer at work!".

No, wait...I'm wrong. It's the SECOND thing I've seen that makes me think that.

The other case is the design of the RGB boards. One of them, I don't recall which, is "left handed", with a reverse
layout of components and traces, as compared to the other two.

The only advantage to the tube layout as it is is that it keeps the anode leads very short as there is an HV splitter block
located between the R and G tubes and another one located between the B and G tubes. So apparently they were all
about keeping anode leads short.

So there's a duplication of effort, the expense of designing extra boards and bulding them, plus a variation in making ONE
tube assembly that doesn't apply to the others, just to keep one wire short?

If I had a parts unit I swear I'd just yank parts and convert this one so that all three systems are the SAME.

It's rare for you to NEED a left handed screw, why put one in if you don't have to?

**Curt Palme** · Posted: Tue Oct 04, 2016 2:04 pm Post subject:

Tell me about it! Very Happy

CIR Engineering · Posted: Tue Oct 04, 2016 2:19 pm Post subject:

Glad you got a G90 Chris, I know you have been wanting one. I remember the first time I opened a G90, I couldn't believe the incredible craftsmanship and was blown away with how well thought out everything was and how every single wire is tied down and has a place. I was blown away.

And yes, the G90 is incredibly serviceable. I can swap three tubes in under 20 minutes with the projector on the ceiling. Every board that has anything on it is also easily accessible and is held in place perfectly while on the ceiling (cough Marquee boards falling onto floor Smile

.

What IC421 chip is on your YA? Did you luck out with a good lot number? If you don't, know post the numbers on IC421 and I'll tell you.

and psst... can you send me those board you forgot to send me before.

craigr