CurtPalme.com Home Theater Forum

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Ben with the thomas tubes the focus coil and deflection coil placement is crucial to good focus. Also if your HV supply is not the 34.9kv model they will to get good focus. a robust power supply provides the best focus for the thomas tubes. At least that is my theory. I think a slightly higher voltage of maybe needed, maybe a 100 or 20 more volts. I wanted to try to crank up a HVPS but was afraid to try it. One reason is I don't have a scope probe able to handle that much juice to get a safe reading

I know when i firsr was testing them I had a M8000 HVPS in my test bed and focus really sucked, i thn read some where that most newer tubes need the higher output HVPS. Sure enough they focused much better. Check your HVPS to see what voltage it is.

Athanasios

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia

Hey Nash,

Long story short, I'm wondering if the tubes I got from CJ are different somehow from Antoine's tubes. Both my HVPS are the 34.9KV model, and at some point years ago I did try moving the focus coil up and down the tube, to little avail. I also used frankenyokes for awhile - they improved the focus, but still not nearly enough. The deflection coil is snug against the bell of the tube, as I assume putting it farther back would be dangerous.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Ohhh, ok. Yeah the other tubes just might be the same tube antoine had but just heavily used. From chips comments on how long the phosphor is lasting i bet its the guns wearing out sooner , which usually doesn't happen in that order.

ok have you cleaned your connections on the CLM chips and daughter boards recently?

But from your explanation of the problem it seams lie a VNB issue or the VIM. It sounds like a spot kill circuit problem. Id loose HV in bright scenes sometimes and other times the image would jsut blank out where it shut the 85 voltage to 0.

Pain in the ass to find that out. You have ti run the PJ with each one VNB off at a time to find the bad VNB.

Nashou

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Each color has it's own over current spot kill circuit.

With the New tubes from Antoine just looking at the phosphor on the tube itself it is the smoothest i have seen on any tube.

Athanasios

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia

A quick note to provide closure to this thread - I can't stand when I have an issue, find an old thread exactly about what I'm looking for, and then the thread trails off with no resolution.

Unfortunately this time there was no positive resolution: I couldn't fix the issue. Every single part (other than cables such as G2 and VIM RCAs) in the projector was swapped with exception of the following: convergence board, astig board, CLM, motherboard, backplane, red tube, blue tube. I have to vent a little here because I've set up so many of my friends and family with CRT projectors, but I kept my very best tubes and chassis, put them together, mount it, build a hushbox, and this happens. I've set up two Sony 12xx projectors for others, as well as a Marquee 8000 and another 8500, and they (knock on wood, I don't WANT them to fail), have run flawlessly for everyone else. Obviously it's bad luck and not design, but it sure feels like a kick in the teeth. It figures, eh? After countless hours sunk into this machine I cut my losses; see my post in the Gray Forum.

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Say Ben

Before you pull the plug here, why not ask Mike Parker to look this over?

.

CRT_Ben · Joined: 28 Aug 2006 Posts: 1684 Location: Northern Virginia

haireez · Posted: Fri Nov 16, 2012 5:14 pm Post subject:

Hi Ben,

2 weeks ago, I had a big headached as to why my Vision 1 was unable to fire up. I had changed almost every boards from my 2nd set of Vision 1 including the motherboard but still couldn't fire up my projector. Embarassed

The only board that was not change is the backplane. Just before I decided to teardown everything apart to replace my spare backplane, I check every cable connectors to ensure no loose cable but still unsuccessful. Crying or Very sad

However, my vision 1 start firing immediately after I start to push up the HVPS cable connector that connect to the backplane. When you released, it stop firing. Therefore, I decided to lightly bent the connector downward and again it start to fire and till now, I do not have any issue with my Vision 1. Wink

Maybe you could try this method and hopefully, your Marquee had the same problem as mine.

GOOD LUCK!!! Laughing