CurtPalme.com Home Theater Forum

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

I have a Marquee 8500 which only recently I notice 4 faint lines across a plain white screen. I swiched colours and noticed its only really appears on the blue. Changing source makes no apparent difference. What I did notice is that when I have the Horizontal frequency at 15hz, all 3 colours have 4 faint lines (very hard to see), but on the blue tube, the lines are more visible. The lines are in a different spot depending on the colour. If I increase the HF to 30hz, the red and green remain the same, but the blue is more noticeable still. When I increase to 48hz, the lines on the blue tube is very visible. Have a look at the photo. I have heard of banding, but I don't know if this is it. I have also tried moving the 'bow' as I heard this causes banding? But this makes no difference... it just makes the lines 'bowed'!

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Any idea what this is and how to fix?

Thanks,

Kevin.

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

Yepp I had the same thing, cleaned the chips on the CLM and the DPB chip U7 especialy. Try that one first as you dont have to remove the DPB from the CLM to fix it. You will need and ic puller to get it off. If you have no cleaner try putting it in and taking out a few times to remove the oxidation. The DPB controls the frequencies so it most likely is that. But also check the HDM and its smaller daughter board. That needs to be cleaned up as well. You may have removeable chips on the smaller boar as well.

Here is some thing to look at :

http://www.avsforum.com/avs-vb/showthread.php?t=1079352&highlight=marquee+flickers

Athanasios

**Curt Palme** · Posted: Fri Feb 27, 2009 1:14 pm Post subject:

I have one CLM here with a similar problem, and it wasn't socketed chips, it's a fault somewhere on the board. If cleaning the chips doesn't work, send it to me and I can repair or swap it out with a spare.

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

**Curt Palme** · Posted: Fri Feb 27, 2009 3:15 pm Post subject:

Funny, I'm learning the importance about buffering caps, despite being in electronics for 30+ years. I just worked on 3 boards, all of which had open caps causing random problems.

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

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

Hello

Try unplugging the blue convergence yoke, see what that does if anything.

.

mp20748 · Posted: Fri Feb 27, 2009 11:58 pm Post subject:

That's a really weird one there.

I'm also thinking the HDM or LVPS.

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

Hello

I can't tell from the picture; either the luminance is unstable or the raster is bunching and spreading.

.

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

I still think its a cold solder joint somewhere on the CLM, look at this thread from AVS. I linked to some pics he had of the same issue. it was acold solder joint on U44, he posted a pic further down the thread.

http://www.avsforum.com/avs-vb/showthread.php?p=14571495#post14571495

Athanasios

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

I unplugged the blue convergence yoke from the back board (in the middle) and the problem went away. Does this narrow things down?

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

Ok... read AVS... let me check U44 as per Nashou66.

BTW... fantastic to get such help from all the top 8500 guys!!!

**Curt Palme** · Posted: Sat Feb 28, 2009 4:53 am Post subject:

It would not be the H board, the lines would be vertical if that was the case. It's either a bad convergence output board (unlikely) or bad info coming from the CLM to the convergence board

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

U44 is good. I tested it with a multimeter. The next step (I suppose) is touch up as many joints as I can with the multimeter looking for dry joints on the CLM. MAN... there are a LOT of places to look.

One thing to note is that its only really happening on the Blue... not all colours. I'm assuming the CLM treats each colour seperately. If not, then maybe its not the CLM?

One of the problems with being in Sydney, Australia , is I think I'm the only bloke within (literally) 10,000miles of the next person with a M8500.

Curt... have you ever spoken to anyone in Australia with a Marquee? If there was, I'd at least have a chance of swapping over the CLM to narrow things down. Also, can you pls send me a PM with cost of a working CLM you might have. If I can't find the problem, it may actually be cheaper to just send a working one rather than sending mine all the way to Vancouver.

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

Is it safe to run the PJ without the DPB? This could narrow it down to the DPB if the fault goes away.

Also, I don't have a chip puller.... Any safe way to remove the chips without one or should I just go buy one just to do this once off diagnosis?!

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

radar · Joined: 05 Dec 2007 Posts: 72 Location: Sydney, Australia

Ok... bought the chip puller (US$7). Pulled all the removable chips off the DPB and refitted them three times each. Put card back in PJ. No change. Pulled all the removable chips off the CLM and refitted them three times each. Put card back in PJ. No change.

Next step... buy a magnifying glass and go over the DPB and CLM and look for dry joints. If I find the little rascal I'll report back here.

If no luck, then it looks like replacement time.

Any further suggestions to isolate given its only the circuits affecting the BLUE tube only?

fishlogan · Joined: 02 Jan 2008 Posts: 14

i thought you get those lines from excessive zone adjustment. If i try to correct my green geometry with too much zone i get that tearing horizontal line like your pic

try adjusting your zones with an all white screen and adjust them too their full hoiz range and se if it makes it better or worse

also, where in aus are you?

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

mp20748 · Posted: Sun Mar 01, 2009 10:47 pm Post subject: