CurtPalme.com Home Theater Forum

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

Hi Guys,
Well, things are moving along nicely with my 'make believe you just got it' 8500 reinstall/resetup. All the mods and updating has really paid off...NO raster or image noise whatsoever now and the pesky horizontal palsy shaking is gone. Thumbs Up

So yay on that score.

I want to take this opportunity to thank everyone here who offered assistance to get to this point and in particular a heartfelt thank you to Athanasios for his unwavering support and assistance, as well as his bottomless well of patience. I'm sure I drove him crazy.

What I have left to conquer is in the middle of each tube (source independent). I couldn't get pix of it for the life of me. I'll try again today some time but in the meantime, to me it looks like a very sheer curtain with the pleats (?) folded gently so that you are actually seeing through three layers of the curtain.

Again, it's faint enough to be a biotch to capture to camera but not so much that I can't see it when looking in the tubes. I haven't gotten around to hanging the freshly coated screen yet (that's another story!) so can't say if it x-fers over.

I scoured the TB's but there wasn't anything that referenced this abberation in the middle of the tube that I could see...just near the edges. If there is something there I missed it because my eyeballs were bleeding after a couple hours of reading. Shocked

Thanks guys!

CZ Eddie · Joined: 23 Mar 2006 Posts: 1601 Location: Austin, TX

Are you sure this TB wouldn't apply?

**Curt Palme** · Posted: Thu Jun 03, 2010 1:45 pm Post subject:

Are you sure this isn't banding?

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

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

Hey,
@ Curt: Well if it is banding then I've got bigger problems because I haven't adjusted a thing on the set yet except for some top/bottom/side pin so I could max the raster and age the new red for a while.

@ Eddie: Yeah I read that one but I discounted it because of this, stated in the begining of the TB:
"This problem occurs very rarely and only when using computer sources that have
horizontal scan frequencies between 45 kHz and 60kHz."
Should I still do the diode change as the TB states or keep looking for a better matched resolution?

@Nash: That looks to be about what I'm seeing although the camera smoothed the fold edges a bit. Looks like the pic you took shows it off to one side of the tube whereas I'm seeing it ~center image.

Raster ringing eh? That's a new term for me. What causes it? (I'm going to go 'fishing' for a possible answer in a minute)

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

Weird..I just stretched the hell out of my newly repaired hernias' (Yup...DOUBLE hernia!) to look into the tubes with C/15, B/25 and it 'looks' like the blue tube is showing banding but the G&R aren't. Like I said all I've adjusted is the pins.
The TB calls for the fix on 50-2003-07P boards; which is what I have so it looks as though I answered my own previous post question.

Good thing I have some better tubes coming; I can see faint faster imaging on G&B now that I've maxed rasters better than it was. Before I change them out I should do some wear leveling on them. Rolling Eyes

**Curt Palme** · Posted: Thu Jun 03, 2010 7:01 pm Post subject:

Well, you can check banding really quickly: Either zero out the top and bottom key and pin, or pull the convergence yoke connectors and see if the problem goes away.

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

I replaced D57 per the TB and all is good now. No more sheer curtain ripple in the middle.

Previously I mentioned that I no longer have horizontal jitter after some resistor and cap replacement throughout the set but....I said that whilst looking directly at the tube faces. It's a totally different story with the lenses on. Shocked

I mean it isn't 'horrible'?..but the image is shaking up and down without a doubt.

Anybody have this and fix it before?...and if so, what caused it and how did you fix it?

*sigh* ONE of these days I'll actually get to watch a movie! Wink

TIA

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

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

JustGreg · Joined: 07 Mar 2006 Posts: 3098 Location: Kenosha, WI

Don't temp me mac! Tweeking and modding is the cats ass but there are times... Twisted Evil

So Nash this is common right out of the box then? That doesn't seem right at all that EHome would engineer a great machine like these and not address that issue. I realize demands on the pj were different in '97 and perhaps that's why it was deemed acceptable.
I guess I'd have to beg to differ on whether it's an issue at the screen or not. I can't see how the jitter wouldn't affect the image at the screen to some degree. Flaring or a softening of the image perhaps? It was there before I replaced caps and such. (which is it when it's up and down...judder or jitter?) I would also think the issue would be more pronounced with standard persistance phosphor such as the stock 180DMB's?

Hmmm. Looking at the service manual (circa '93...my pj is a '97) the output stage ripple and current filtering is handled by capacitors C201, 202, 203, and 205. *sigh* There's too many points for external noise to be slipping into the image...the rails, the CLM, Stig Amp, etc, etc. Without a scope this is like pushing a rope. Hey I made a tekkie joke! Mr. Green

I didn't replace caps 109 though 609, or caps 117 through 617 as they tested fine with a DMM and in circuit ESR tester. Those 2 tools aren't the end-all for cap testing but usually (from what I've read) a good indicator of a caps health. I'm going to go ahead and replace them anyway to rule that out, as well as replace many of the resistors; especially in the filtering circuits as they are responsible for diode latching/switching and feedback voltages.

I just came back from the HT where I powered the pj off and disconnected the CVA to see if the shake was still there. The only thing shaking was me. Hey...is it normal to get zapped just touching the cable terminal connector at the CVA? Shocked

It was definately a static discharge. I didn't have the other hand on anything and the hand pulling the plug(s) wasn't leaning up against the frame and no part of me was near the HV leads that I have pulled off to one side and secured loosely with temporary wire ties. Wowza. Shocked

I didn't unplug the set as the CVA is energized upon powerup...right? Dayum!!

Shocking experience aside, I didn't see any jitter with internal sources and had no desire to feed it a source after the zapping incident.

OK...I'm done for the day while I still have a pulse. Rolling Eyes