CurtPalme.com Home Theater Forum

haireez · Posted: Fri Mar 25, 2016 7:48 am Post subject: 9518LC - Adjust Start Pulse

Hi All,

Just got a set from Curt and it's version 6.1. There's one additional features that I'm not familiar with and hope someone know what or how this features work to improve the picture quality.

In the menu, there is "Adjust Start Pulse' and if you select it, there's additional features for you to adjust convergence delay band 1-4, Stigmator delay, Geometry Correction and focus delay. Does anyone familair with this function and how to do this?

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4379 Location: Phoenix

Hello

Those were previously hidden in the supersecret menu, the default values for those is 50

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

What those do is adjust the timing of the convergence and stigmator signals, so that they can be adjusted so that
the actual points that are adjusted can be matched up to the displayed adjustment points on the adjustment screen.

The bands are for different ranges of scan rate.

Here's how to see what this does. Don't worry, it's safe.

Here's a graphic representation of what it controls.

The top image shows what convergence adjustments look like when the delay is set correctly. The center of each convergence movement lines up with the points where the grid lines cross.

The lower images shows what happens when the start pulses are set incorrectly. The center of the convergence movements do NOT match up to the grid crossings.

There are four bands, which are frequency bands. You will have to be in the right range of scan rates to see the results of any changes.

You can select your scan rates from the menu settings. You'll need to choose the right ones for the right bands.

If this image is useful to you, save it now. I'm out of room on ny photobucket account and will take it down shortly.

Before you make any adjustments in this screen, check and see if the convergence works correctly, with the adjustments alll nicely centered over the grid crossings.

The same principle applies to the stigmator adjustments but they can be a little harder to visualize as astig is comparatively subtle.

tschaeikaei · Joined: 08 Apr 2013 Posts: 489 Location: Germany/Saarland

Hi Tim,
having the same problem on my 4.4 version Marquee, could you tell me how to get into the secret menu?
I've managed to minimize the convergence delay/offset a bit by manually rotating the yoke, but it's not completely gone.
Thank you, Regards, Julian

haireez · Posted: Sat Mar 26, 2016 9:10 am Post subject:

Thanks CMJohnson. It does make sense with your explanation. However right now, there is an arc in my set while watching movies for 1hr and now the tubes are not able to fire.

Upon checking, I saw one burnt resistor at the other side of the HDM but unable to finalize the actual value but I'm guessing it's red, red and black. Can you confirm if the value is correct as I understand that you also have a 9518LC set as well.

haireez · Posted: Sat Mar 26, 2016 9:13 am Post subject:

Photo of burnt resistor on 9518LC HDM (Refer next message)

haireez · Posted: Sat Mar 26, 2016 9:14 am Post subject:

Photo of burnt resistor on 9518LC HDM (other side of main board)

CM,

Could you please confirm the resistor value please? Thanks.

**AnalogRocks** · Posted: Sat Mar 26, 2016 12:54 pm Post subject:

CM, I attached the images to your post. No need to max out your photobucket account.

~AR

tschaeikaei · Joined: 08 Apr 2013 Posts: 489 Location: Germany/Saarland

Is this resistor below Q20? I'm about 99% sure...
So if I'm right, do the following.
Desolder Q20, check if there is conductivity (about 8 or 10Ohms) between source and drain.
It most certainly will be. Also check for conductivity between gate and the other two pins.
conductivity only between S and D: Check D21 and D22. Check R93 and R96.
The diodes will conduct both directions, the resistors will be open. The resistor you photographed is R1001 2.2Ohms, 1/3W.
R93 and R96 are parallel to R1001 and both 1Ohm 1/3W.
Also check R62 and R91.
If there is conductivity between gate and the other pins of Q20, you're gonna replace R98.
No you can throw away that heatsink and Q20, take a new IRF730 or MTP5N40 and mount the transistor onto the main heatsink of the HDM. You'll have to drill a hole and use short cables to wire it.
Make sure it's double isolated from the heatsink.
In some cases (if Q20's gate shorted), you may need to replace U12. But it isn't that common.

Why does this all happen?
Q20 is likely to fail if it gets to hot. That "mickey mouse" heatsink is way to small.
When it gets too hot, it bricks D and S or all three together and -luckily- blows the fusible resistors.
Make sure you use the right power (1/3W ) resistors. If not, it will destroy much more if it fails again.
Do not use other types of mosfet, even with better specs. I did use a IRF740, which blew after a few minutes.

Regards, Julian

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

The post above is correct.

Resistors that are burned up are ALMOST never the problem, they are a symptom of another problem.

The simplest way to address this problem is with a new HDM. Ask Curt for one, I am SURE he has them falling out of his ears.

tschaeikaei · Joined: 08 Apr 2013 Posts: 489 Location: Germany/Saarland

I know as I've had that damn problem with Q20 overheating three times in the last weeks.
So i recommend mounting Q20 on the main heat sink and wire it with short cables.
I had mounted it to a about twice as large heat sink (comparing to the original) before, but it wasn't enough.
Those resistors are so- called fusible resistors, meaning they act like a fuse. Therefore, they are marked in the datasheet
with a warning sign. Electrohome/Christie/VDC used them all over the Marquee, and I am sure other manufacturers do as well.
Regards, Julian

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

Ask yourself, what's drawing enough current to cause overheating?

See which tube's yoke is being fed by the channel that's overheating. And replace that focus yoke with another one.

I've seen a few yokes that had a shorted winding or two. They then draw too much current. There are some dropping
resistors located on the connector boards on the yoke itself. Check to see if they show signs of overheating as well.

Remember, a lot of Marquees in service today are more than 20 years old. So far I've only used chassis that had 50K or more hours on them when I first got them. After so long, a lot of parts can and do show signs of wear and tear just due to being warm and running for so many hours.

mp20748 · Posted: Sun Mar 27, 2016 2:49 am Post subject:

When a Marquee HDM blows a fusible resistor, it is time to replace the HDM or have it repaired.

Repair should only be attempted If you have a test bed set, or you risk damaging your CRT's from horizontal collapse.

tschaeikaei · Joined: 08 Apr 2013 Posts: 489 Location: Germany/Saarland

Mr. Johnson, I recommend you to look into the schematics. Q20 doesn't drive the yokes.
In my case the overheating was caused because of the lack of cooling.
I had to disconnect the HDM fan in order to perform the mechanical projector setup
(modded ventilating system, see here: http://www.curtpalme.com/forum/viewtopic.php?t=38445&highlight=fan+mod+marquee+others )
which sits on the outer case.
I've monitored the HDM temperature (sensor on the big heatsink) via my fan control software and because of only low internal horizontal frequencies while setting up it wasn't too high.
Q20 didn't have an own sensor, so i could not monitor the temp and it overheated.
Second fail was because of the additional fan falling off (tape didn't hold), third time because of the IRF740 i had to use.
It has about double the input and output capacitance compared to a IRF730 and that caused the overheat.
This repair is 100% safe, i've done it three times, remember? Nothing happened to the tubes.
There's more on the HDM than just horizontal deflection. And the self check on the projectors start up seems pretty safe to me.
It has been running for about 3 hours without any problems now.
I've taken out and measured various caps including the famous C50. Nothing to worry about. Capacity ok, no bulging, ESR ok,
Vdrop ok.

It's always better to have a test projector with worn/burnt tubes, but in this particular case, it is not necessary.

Regards, Julian

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

Well, be that as it may, it's still good to have a known good spare HDM and I'd recommend you get one from Curt. Or somebody.
.

tschaeikaei · Joined: 08 Apr 2013 Posts: 489 Location: Germany/Saarland

Sure, why not. But it's not forbidden to repair things, is it?

mp20748 · Posted: Sun Mar 27, 2016 2:58 pm Post subject:

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

I concur with Mike. I won't attempt to repair a deflection board as the consequence of a failure of a deflection circuit can be
burned and ruined tubes.

I won't even test a modified deflection yoke on a "good" tube. It's got to be one that I can stand to see damaged.
Only when it's proven good on the test mule will I approve it for installation in my projector.

Which reminds me of something....

**Curt Palme** · Posted: Sun Mar 27, 2016 5:38 pm Post subject:

this is one of the NOS sets that I sold that had the tubes smashed. He had an HV arc, my guess is from one of the tube's HV leads that he put in. The HDM is a Nov 2006 vintage, so it's one of the latest revisions, and I don't believe the older versions have that resistor on the back of the board. As a result, I don't have the schematic, and can't really be of assistance remotely with the repair of those boards. I've suggested that he send it in to me for repair.

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

Were there any glycol leaks due to the smashed tubes? If any got on a board, it could cause odd problems.