CurtPalme.com Home Theater Forum

Sparky015 · Posted: Fri Aug 27, 2010 12:46 am Post subject:

You said the previous owner is an accomplished solderer, but I would check his work over with a magnifying glass too. You wouldn't believe how a minor cold solder joint behaves as temperature changes, and most can't be picked up by the naked eye. 5-10X magnifying power if you got it. I would definitely look over the HDM and it's connections though.

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

There's an increasing in loudness high pitched whine that comes from the HVPS when the convergence grid is up, the whine subsides when video is back on the screen.

Also, when adjusting the side pin, it "snapped" to a no adjustment position, even though the setting was in the mid 30's. A slight touch to the adjustment put it back to normal...

Is Geometry control also on the HDM ? That would certainly point more to that board than another one, wouldn't it ?

The fluctuating brightness looks more like a lack of control over the baseline G2 and drive than a video problem. Sometimes the image looks very dull and lifeless, like the G2 and drive are way too low, then bam, its a really punchy, bright image...And the fluctuating happens with internally generated patterns as well as video...

I'm trying to capture these symptoms on video, but they come and go quickly. When its working properly, it looks very good...

PS: The previous owner payed someone, a semi-professional, to do the mods on the neckboards, I would trust the soldering job, I've seen his work before, it is good. Also, I'm not capable of actually doing any soldering myself. Never had the opportunity to get any training, and learning on my own isn't something I'm capable of. I can do some deductive trouble shooting, and have a fairly good memory of fixes that I've read about, but not having any soldering capabilities is pretty much why this will likely end up parted if I can't nail it down to something that can be solved with a board swap...

mp20748 · Posted: Fri Aug 27, 2010 1:46 am Post subject:

tse · Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.

There is an IC on one of the boards (sorry, no schematics at home) that has two caps soldered to it. Little yellow guys. There is a change to that mod that puts a couple of resistors in series with the caps that helps to filter out some garbage on the serial bus that runs throughout the projector. The garbage on the bus causes stuff like what you descibe. Settings changing then snap back to the right setting with just a touch of the remote control buttons. I'll get more info tomorrow.

Scott

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

I think its U10 on the Vim right Scott?

Athanasios

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

This is a brief piece of video showing the fluctuating brightness:

View My Video

Here's one showing, towards the end, the size snapping:

View My Video

The VIM is an 50-2035-03P VIM, and I don't see any caps or anything added over any chips anywhere on it...is this one of the "good" VIM's ?

zGman · Joined: 22 May 2006 Posts: 599

Thats a good shot on the video...

Two things I noticed re-reading this thread - besides all the great ideas,
I didn't get the "LC" part initially, that should look really nice and be worth
saving, and second, I wondered if you had tried Scott's idea of disconnecting
the VNB's individually? It seemed that you had swapped them around, but that's not quite
the same if one is somehow internally shorting, etc...??? And I am not certain from
his post exactly which wires should be disconnected, probably don't want G2 lying around?

G

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

In the past when I was told to disconnect a VNB, it was by unplugging the white multi pin connector at the bottom, I assume that is how I'd do it now ?
You're right, I haven't tried that as a trouble shooting step, I've only swapped neckboards between tubes without changing the symptoms at all...

You're also right about it looking REALLY nice...when it works properly for a few minutes at a time...and its certainly worth "saving" by the quality of the image, but I can't afford to put hundreds of dollars into doing it, regardless of how nice the image is, unfortunately....its not 2001 any more...

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

That's what I wanted you to do. Each disconnected one at a time, leave it disconnected as you do the next if it still does the problem. When your down to only one connected put the first one back on and remove the last one not tested .

Athanasios

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

Looking at the VIM, I noticed this:

What does that chip do ?

stefuel · Posted: Fri Aug 27, 2010 10:42 am Post subject:

Unplug the Marquee and plug in a AmPro Laughing

HK-Steve · Posted: Fri Aug 27, 2010 10:56 am Post subject:

The pulsing brightness I have seen before on a friends projector,
The VIM was the problem, and I was never able to fix it.

Changed the VIM, had no pulsing after that.

Hopefully you have a spare VIM or someone close that can swap one in to try.

Cheers
Steve

HK-Steve · Posted: Fri Aug 27, 2010 10:59 am Post subject:

That corrosion, or what ever it is around the 5 pins of U35,
Get some contact cleaner, and scrub gently it with a toothbrush.

I don't think that is causing any issues, but it should not be there.

Cheers
Steve

HK-Steve · Posted: Fri Aug 27, 2010 11:08 am Post subject:

Just looking at you VIM pic,
you need to do the technical updates on it also,
this will remove some of the problems with it that have been resolved.

well worth doing.

see here,
http://www.curtpalme.com/docs/ElectrohomeMarqueeTechnicalBulletin_LineFix.pdf

I thought there was another one for the 03P VIM??

Cheers
Steve

Sparky015 · Posted: Fri Aug 27, 2010 12:29 pm Post subject:

There is a tech bulletin for the "snapping" as Tim and Steve pointed out. You need soldering skills for those, although I'm a bit surprised an 2001 wouldn't have them all already. I have an 02P VIM with all the tech bulletins done to it. Not sure where in the US you are, but I'd be willing to send it to you to swap in if you like. It's my spare VIM, so it's just sitting.

Good video of the fluctuating brightness. Very annoying! I can see why you wouldn't want to live with it.

Sparky015 · Posted: Fri Aug 27, 2010 12:34 pm Post subject:

I guess there are a few in 2002 and 2003. This one may fix your HV shutdown issue.

http://www.curtpalme.com/docs/ElectrohomeMarqueeTechnicalBulletin_VDCDS_TFB_003.pdf

Elaine Benes · Joined: 25 Apr 2006 Posts: 1416

tse · Joined: 03 May 2006 Posts: 1014 Location: Sweatbucket, Fl.

The fluctuating brightness might be a VIM problem. The serial bus (dac bus) evidently has had problems from the beginning. Electrohome put 100pF or 330pF caps from the clock and data lines of U10 to ground. When VDC made the split pack (two box w/umbilical cable) units the bus started acting up again. Attaches are pics of the schematic (VDC) and mod on the PCB. A couple of 100pF caps will probably fix it. If not try the VDC mod of 10 ohm resistors in series with 1000pF caps.

Scott

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

Scott, you've been posting a lot this week so far....are you on vacation?

Smile

Nashou