or Connect
AVS › AVS Forum › Display Devices › Rear Projection Units › 2008 Samsung HL61A750 LED DLP owners thread and FAQ
New Posts  All Forums:Forum Nav:

2008 Samsung HL61A750 LED DLP owners thread and FAQ - Page 497

post #14881 of 15633
Quote:
Originally Posted by rtchinn View Post

-----

In my opinion, (and you are certainly entitled to yours), that defines a way for failure. Three dots, 1/4 the size of a grain of rice?... are you serious?

Yes, I am absolutely serious.

Based on the small surface area in this specific application ..any more than that amount would be sheer overkill. These mating surfaces are profoundly rectangular. If they were perfectly square mating surfaces with similar surface area, then I would recommend a single dot dead center no larger than half a grain of rice.

Quote:


With over 30 years of Electronics Industry work, over 25 of those as a design engineer, and I've never heard or read any thermal engineering source recommend such tactic.

I don't doubt your engineering prowess, and am not here to scuffle, but rather to inform. I'm sure you have heard of the center dot/small pea method which is most commonly used for mainframe and critical server CPU installations? This is ideal for the larger surface area perfectly square shaped PC class CPU heat spreaders. We are dealing with surfaces that are much smaller here and much less thermal compound suffices.

Quote:


YES... I'd agree that many people get themselves into trouble by following the "apply liberally" method of long ago, but likewise I believe, from my experience, your prescribed method goes to the opposite extreme.

My method is precisely perfect for this application. Additionally, spreading tests have shown that multiple dots spread evenly and do not introduce air gaps.

Quote:


Additionally, if both surfaces are not cleaned, ANYTHING left on the (in this case) DMD heat spreader, will prevent the thermal compound from spreading out to cover the entire mating surface.. and cause VERY quick failure.

I agree that it would be ideal to clean both surfaces, but not convenient nor essential in this particular case. When the DMD heat sink is removed, the thermal pad will be cleanly extracted and completely affixed to the base of the heat sink.

The DMD's heat spreader is recessed deep within a padded enclosure making cleaning impractical. One would likely introduce contamination to the heat spreader by probing the cavity in a cleaning attempt. Again, the pad will separate cleanly from the DMD heat spreader leaving behind no residue.

Quote:


My modifications to your instructions would be:

Use a "credit card" (or similar) to scrape the old material from both surfaces, THEN clean them with the prescribed Alcohol method, but use a Q-tip moistened in alcohol to clean the DMD surface IF there is any residue or pieces of the old thermal pad left. Both surfaces must be 100% CLEAN when done.

WAIT for both surfaces to completely dry, then apply a VERY thin layer of thermal compound to ONE surface (the heatsink), spreading it with the same (but CLEANED) credit card. The proper amount will be when there are streaks of the heatsink showing through the compound, but not large areas. Be CERTAIN that there are no "bumps" in the layer of compound, as this would indicate dried 'globs' of the base material, and would prevent the material from spreading out when reattached.

The goal is to apply enough across the entire mating surface that the pressure applied by the heatsink spring clip will cause the compound to "ooze" and spread out to fill-in the gaps - once the heat comes on.

On big problem with "dots" is that you have minimal thermal conduction to begin with, when the set is first operated. Then you are expecting these 3 "piles" of compound to spread out over the entire surface, by itself... and I can guarantee you that this method will leave areas of mating surface without thermally conductive compound... which means less heat transfer, and more prone to failure. Some "silver arctic" type compounds are very thick, and resist spreading out without significant pressure.

Q-Tips should never be used to clean thermally critical surfaces, potential stray cotton fibers would be extremely detrimental to conduction.

The credit card spread method is foolish as it is known to incorporate micro air pockets within the compound no matter how careful you are.

Arctic Silver 5 (which I have recommended) has excellent initial spreading performance. The amount I specified is enough to fill all surface imperfections, cover the entire surface area and ensure that no dead air space will exist.

Quote:


This is the precise reason most manufacturers have chosen the thermal pad method... it eliminates human error in applying the precise amount required. Thermal pads are NOT BAD... in general. Some are great, some are not so... but when properly engineered and applied, they do the job VERY well.

True, but the thermal pads chosen for use in these TVs are exceptionally poor.

Quote:


One problem with "thermal paste" is that MANY products have a liquid carrier that completely evaporates in VERY short order with the applied heat. What happens then is that the actual thermal transfer material becomes hard (or even brittle), and when the device heats up and thermal creep happens between the two surfaces, the dried up base material "bunches up", and no longer "goes with the flow"... it no longer allows for movement... even on the small scale we're talking about. This obviously results in thermal failure.

Yes, aka cheapo silicone/zinc oxide based concoctions. ...Hence my recommendation for AS5.

Quote:


This "creep" is CRITICALLY important when the heatsink is not directly fastened TO the device generating the heat. If there is no room for "creep", then it is much less of a problem. HOWEVER... in our application (Samsung DLP), the heatsink is NOT "attached" to the DMD... it's attached to the mechanical hardware around the DMD.

Yes, I am already aware of potential binding issues due to the aging of poorly designed thermal compounds

...Hence my recommendation for AS5. AS5 is guaranteed to never creep nor harden.

Quote:


Well engineered Thermal Pads have high temperature (silicone) in them (which is expensive), which acts as a permanent lubricant, and does not dry out during the lifetime of the product.

I just pulled the heatsink from one of my used spares (yes, Samsung LED DLP), and the pad (light yellow colored) was still pliable, and able to 'slide' across the DMD surface easily... which tells me Samsung Engineers probably did their homework.

I grade the result of their thermodynamics homework a resounding F.

Quote:


I'm not saying it can't be improved upon, but I am saying that if it ain't broke, don't TRY to fix it! Without proper test conditions (measuring the actual DMD device operating temperature with BOTH types of thermal transfer material), you really do not 'know' that you have done it any good... or bad.

...And this is where I think you will listen to my reason:

I have measured the net benefit of losing the pad.

Prior to initial HS removal, I detached the DMD cooling fan and powered up the TV....then tuned to a dead-signal, static NTSC channel. (TI datasheets specify that this will stress the DMD to the max and generate the most heat)

***After 2 minutes of on-time the DMD heat sink _was still room temperature (71F)_***

I then replaced the pad with AS5 exactly as I have recommended. Would you like to know what happened next?....

***After 2 minutes of on-time the heat sink was very warm to the touch (121F)_***

The results need no further explanation.

Quote:


BTW... stuck pixels can't be directly tied to a thermal problem. Let's face it... the DMD is a bit of a "magical mystery" anyway... it's an amazing technology, but it is still an electro-mechanical device... those million+ microscopic mirrors are moving billions of times, and SOME WILL FAIL... maybe not in my set, maybe not in yours... but some will fail.

Sorry Sir, you are misinformed and incorrect.

There is official documentation direct from TI that emphasizes the dire importance of efficient heat dissipation on the DMD panel. There is a profound DMD sensitivity to heat. Failures (aka stuck pixels) are common within 2000hrs of service if the guidelines are not followed.

I have easy access to all of the TI datasheets I could ever want as a member of their engineering discussion board.

Quote:


Sorry if I came across too harshly, but I'm passionate about engineering, and sometimes these kinds of issues get my ire up.

I am as well, and tend to get worked up over issues myself. It's fine..no hard feelings.
post #14882 of 15633
Quote:
Originally Posted by taz291819 View Post

I'm not sure of the three dots, but using the "dot" method is what I've read and used for years, and never had a problem myself.

Yes, I've also read of the "credit card" method, though I've never used it.

EDIT:

The method I've read and practiced was you put a single dot about the size of a pea, apply the heatsink, twist once about 25-degrees clockwise, twist counter-clockwise 50-degrees, then finally back to center. This was for an Intel CPU btw. The first time I did it, I removed the heatsink, and low and behold, the Arctic Silver spread out evenly.

I went with three small dots due to the very small size of the contact surfaces and their excessively rectangular shape. A single dot dead center is proper only when the surfaces are equilateral (perfectly square or triangular...or in the case of a perfect circle). Multiple dots have been shown in heat sink/thermal compound spreading tests to spread uniformly and not introduce air gaps (just as effective as the single dot method).
post #14883 of 15633
Quote:
Originally Posted by taz291819 View Post

EDIT: Ok, figured out how to be able to change the settings in the User menu. In the SM, I changed P-Mode back to Movie.

Suppose that's one possible way around it, but are you absolutely positive that doing so didn't skew your calibrated settings? I recall Lee coming up with another tactic while skimming through the calibration thread one night.

Unfortunately I never bothered to read much into it. I think it involved adding additional parameters to the "Expert D-Setting" subcategory of the SM. The changes had to be made to each input source individually.

Look into the "jrcorwin" calibration thread for specifics:

http://www.avsforum.com/avs-vb/showthread.php?t=1134887



EDIT: PASTED FROM LEE'S INSTRUCTIONS WITHIN THE CALIBRATION THREAD.....



Modifying and Keeping your Movie Mode settings:

You will need to set this for each input that you use.

With the TV off,
Enter the Service Menu using Mute-1-8-2-Power on the remote.

Cursor RIGHT on OptionByte Menu
Cursor DOWN until you get to Expert Adj. (OFF if you've never enabled it)
Cursor RIGHT to Select it.
Cursor RIGHT to toggle on/off, Leave it set to ON.
Hit MENU button on remote to take you out of this menu.
Cursor DOWN until you get to Expert Settings.
Cursor RIGHT to select Calibration.
Cursor RIGHT to toggle it ON
*From this point, you can just cursor DOWN to get to the next item, no need to hit MENU on the remote.
Cursor DOWN to P-MODE
Cursor RIGHT to select it.
Cursor RIGHT to toggle Movie/Calibration

The difference between Movie and Calibration in this menu will be:

Calibration mode will gray out picture settings in the user menus, using settings you set up in the Expert Menus.
You will notice that your Picture Mode settings will now be: Dynamic, Standard, Calibration(instead of Movie). When you power back on your TV, you will come up in Picture Mode 'Calibration', but only on the input you started the system menu in. On the other inputs, you will have to change your picture mode to Calibration.

P-MODE Movie will only retain your Contrast, Brightness, Sharpness, Color, and Tint Settings, you may have to go into Detailed Settings and Picture Options and set those to where you want.

Cursor DOWN to Color Tone.
Cursor RIGHT or LEFT to change to WARM2(or whatever Color Tone you want)
Cursor DOWN to Contrast
Cursor RIGHT/LEFT to set your chosen value
Cursor DOWN to Brightness
Cursor RIGHT/LEFT to set your chosen value
Cursor DOWN to Color
Cursor RIGHT/LEFT to set your chosen value
Cursor DOWN to Tint
CURSOR LEFT/RIGHT to set your chosen value
CURSOR DOWN to Sharpness
CURSOR LEFT/RIGHT to set your chosen value
Hit MENU button twice to get back to main menu

Cursor DOWN to Expert D-Setting
Cursor RIGHT to Select
Change each item to what you want when using Picture Mode 'Calibration', using cursor controls.
When done, hit MENU on remote to get back to main menu.
Cursor DOWN to Expert Others
Change each item that's not grayed out to what you want when using Picture Mode 'Calibration'
When done, hit MENU on remote to get back to main menu.

Power off the TV.
Power on the TV, check your settings, modify what you need to in Detailed Settings and Picture Options.

Additional:

Changing your default STANDARD Mode Contrast, Brightness, Sharpness, Color, and Tint Settings:

Enter the Service Menu
Cursor DOWN to EPA STANDARD
Cursor RIGHT to SELECT
Cursor RIGHT on Standard Contrast
Cursor RIGHT/LEFT to level you want
Cursor DOWN to next item, cursor LEFT/RIGHT to adjust.
When you've gone through all the items, hit MENU on remote.
Power off TV.

Power back on TV,
Change to the next input you use. Repeat steps above.
post #14884 of 15633
Yeah, that's what i did. In the expert menu, I changed p-mode from calibration back to movie.
post #14885 of 15633
Quote:
Originally Posted by taz291819 View Post

Yeah, that's what i did. In the expert menu, I changed p-mode from calibration back to movie.

Yes, it seems pointless to leave p-mode toggled to calibration. It's much less of a hassle to set it to movie.

BTW, I may have just found a possible SM tweak to increase black level performance still further. Will try it out soon then share the results.
post #14886 of 15633
Quote:
Originally Posted by KewlK View Post

Yes, it seems pointless to leave p-mode toggled to calibration. It's much less of a hassle to set it to movie.

When P-Mode is set to Calibration, it keeps you from losing your user menu (for Movie Mode) settings when exiting the service menu.
post #14887 of 15633
Anyone needing fan #3 they are available both used and new on eBay. Search for
a NOVOI G6015S12B2. I tried fans I was able to get locally and while they ran
and the TV worked the FAN #3 error message was still displayed.
post #14888 of 15633
Has anyone else noticed random horizontal bars across the screen most noticeable during dark scenes?
post #14889 of 15633
I've got a 3/4" wide vertical grey shadow running top to bottom along the left edge of the screen (viewed from the front) on my HL67A750. The TV is about 3 years old. Anyone know what causes this? Picture data is still visible in this shadowed area, it's just darker than everything else. This anomaly occurs on all 3 HDMI inputs.
post #14890 of 15633
Quote:
Originally Posted by rahull View Post

Anyone needing fan #3 they are available both used and new on eBay. Search for
a NOVOI G6015S12B2. I tried fans I was able to get locally and while they ran
and the TV worked the FAN #3 error message was still displayed.

Have you tried the Samsung Parts site?

Parts_and_Accessories&Category=HL61A750A1F
post #14891 of 15633
Quote:
Originally Posted by Lee Bailey View Post

Have you tried the Samsung Parts site?

Parts_and_Accessories&Category=HL61A750A1F

I looked at one site and it indicated they were out nation wide. I
ordered a new one on eBay (shipped from Los Angeles) and all
is good now. I would guess the ones I tried from local sources
that indicated a fan #3 error (even though the TV worked) saw
a error in the yellow speed wire connection.
post #14892 of 15633
Quote:
Originally Posted by putox1051 View Post

I've got a 3/4" wide vertical grey shadow running top to bottom along the left edge of the screen (viewed from the front) on my HL67A750. The TV is about 3 years old. Anyone know what causes this? Picture data is still visible in this shadowed area, it's just darker than everything else. This anomaly occurs on all 3 HDMI inputs.

Scroll down to the very bottom of this page and you should find several links posted. One has to do with your problem as it seems to be a common issue as our sets age.
post #14893 of 15633
I'm working on this particular set and have replaced the red and blue led display Phlat light. Have all colors but background is too green. Any suggestions as what i need to do next.
post #14894 of 15633
Thanks for the Thread mike! this is awesome!
post #14895 of 15633
Quote:
Originally Posted by raylloydtv View Post

Have all colors but background is too green. Any suggestions as what i need to do next.

Can you be more specific..just how badly is green domineering the image? Is it apparent on all inputs?

Would it best be described as a slight overall tint, or is it so bad that it's practically like looking through a green filter?

If it's the former, an ISF (or DIY) calibration is the solution.

However, if the green truly is nasty, I would strongly suspect the integrity of the LED driver board.
post #14896 of 15633
Has anyone ever taken or seen a black level measurement on these? I would very interested in seeing that.
post #14897 of 15633
Thanks! Got into Service menu , turned CCA off and made adjustments. Fixed problem.
post #14898 of 15633
Quote:
Originally Posted by RedOctober205 View Post

Has anyone ever taken or seen a black level measurement on these? I would very interested in seeing that.

It's a weakness of this display. MLL measures about .025 foot Lamberts.
post #14899 of 15633
Quote:
Originally Posted by buzzard767 View Post


It's a weakness of this display. MLL measures about .025 foot Lamberts.

Thanks. I am about to give mine to someone and pick up a new display. I know what the visual difference will be, but I was interested in that actual measurement. Thanks again.
post #14900 of 15633
Hello,

I am new to this forum and was seeking some advice about my Samsung DLP LED TV. After almost 4 years, my TV just refused to power-up. All that is happening was the lights in front of the TV just started blinking. I called Samsung and they told me that the "LED lamp" needs to be replaced. I told them that is highly unlikely since the LEDs have an estimated life of 20000 hours! I was also told that since it is over a year old that the warranty is over. Anyway, I heeded their recommendation and called the parts department to order the LEDs. After explaining to the parts guy my situation, he told me that it is highly unlikely that the LEDs are the culprit since, if they fail, they usually fail one at a time, either the red, the green, or the blue fails, and NOT all at the same time. So I am not unsure what to do? My dad thinks its the LEDs and wants me to inquire about replacing all three LEDs (which we could do ourselves) which I think would be a waste since it is most likely not the cause of the problem. Another option is to call a recommended TV repair shop who would run the diagnostics and find/fix the problem. That I know would not be cheap, and if it is going to cause around $500, I would rather just add $500 more and buy a 60" LG LED 120HZ TV for $999 at Best Buy. I was wondering what is your suggestion on this matter?

Thanks in advance,
Andy
post #14901 of 15633
Quote:
Originally Posted by AndySIII View Post

Hello,

I am new to this forum and was seeking some advice about my Samsung DLP LED TV. After almost 4 years, my TV just refused to power-up. All that is happening was the lights in front of the TV just started blinking. I called Samsung and they told me that the "LED lamp" needs to be replaced. I told them that is highly unlikely since the LEDs have an estimated life of 20000 hours! I was also told that since it is over a year old that the warranty is over. Anyway, I heeded their recommendation and called the parts department to order the LEDs. After explaining to the parts guy my situation, he told me that it is highly unlikely that the LEDs are the culprit since, if they fail, they usually fail one at a time, either the red, the green, or the blue fails, and NOT all at the same time. So I am not unsure what to do? My dad thinks its the LEDs and wants me to inquire about replacing all three LEDs (which we could do ourselves) which I think would be a waste since it is most likely not the cause of the problem. Another option is to call a recommended TV repair shop who would run the diagnostics and find/fix the problem. That I know would not be cheap, and if it is going to cause around $500, I would rather just add $500 more and buy a 60" LG LED 120HZ TV for $999 at Best Buy. I was wondering what is your suggestion on this matter?

Thanks in advance,
Andy


There are a lot of threads within this forum in regards to checking the power supplies on this set. That is the most likely situation you are facing. If you don't feel comfortable making voltage measurements then you have limited options.
post #14902 of 15633
Does anyone know if you can disable the red sync signal in 3d mode anywhere? I recently upgraded to the MonsterVision 3d glasses with this TV which use the VESA 3d sync port on the set in order to create a RF sync. (BTW: quick plug, these glasses are great!) Anyway, now I don't need that DLP Link signal and was wondering if it can be disabled to remove some of the red tinge..
post #14903 of 15633
Quote:
Originally Posted by KewlK View Post

Thanks for the incite Lee. I was suffering from a case of "cerebral flatulence".

After rehashing your first "Calibration Steps" posting it all came back again.

I have a couple questions:

-Have you ever experimented with tweaking the "Backlight" control under "Expert Setting"? Curious to know if reducing this value could help improve black level performance a bit more.

EDIT: Adjustment ramp is 0-10 (11 point scale), much finer LED luminosity control than simply Min/Low/Medium/High/Max/Auto. Hopefully 0 does not equate to regular Min or shut the LEDs completely off. If the LEDs become slightly dimmer than the normal Min setting, I'd be very happy. Will try it soon.

-Within "Expert Others" the very last parameter is "Auto Motion Plus". I suppose that this is just an alias for DNIe? Even though DNIe is basically useless, it's kind of neat to see that Samsung included a control that offers it at different flavors...Off/Low/Mid/High.

If tamed appropriately, perhaps it could be useful for certain video games by providing a little extra "pop effect"


Did you have a chance to adjust the LED? If so, I'm very curious to see if it improved black level performace at all. I set my LED control to Min but wish the blacks were a tad better.
post #14904 of 15633
I've had my 61A750 for 3 years now and I love the set as much as the day I got it. I've read KewlK's post about cleaning the LED's a couple times a year. I did the other day see a quick red shift on the left side. It went away quickly. So from reading these posts I'm thinking I very well may have problems soon. BTW=I've had my LED setting always on Auto. I will lower it now after reading these threads.

My question: What is the best way to access the rear of the set in order to clean these LED's? Is there a video on YouTube on how to do this?

Thanks for your help.

Scott
post #14905 of 15633
Quote:
Originally Posted by NetCoder View Post

Does anyone know if you can disable the red sync signal in 3d mode anywhere? I recently upgraded to the MonsterVision 3d glasses with this TV which use the VESA 3d sync port on the set in order to create a RF sync. (BTW: quick plug, these glasses are great!) Anyway, now I don't need that DLP Link signal and was wondering if it can be disabled to remove some of the red tinge..

I've been looking for a solution to this as well for a long time and have yet to find one. When I posted here and over in the 3D thread for this set, most people said they could never see what I was referring to when I talked about the "red tint" when 3D is enabled. Most thought I referred to the red ghosting when you watch 3D and the input is named to anything but "PC" (which it is SUPPOSED to be named to for 3D, btw).

I'm glad there is someone else inquiring about the same thing and I'd love for there to be an easy solution that someone has found since my last visit to the forums. While I can barely notice the red tint anymore while wearing the glasses, I can't help but think the 3D picture would look even better if it could some how be disabled.

For anyone wondering, this is what we're referring to:

post #14906 of 15633
I don't believe the red tint in the 3D mode can be disabled. The red tint is a lot less when you wear 3D glasses (with an emitter) and I believe eliminated when you use DLP link glasses.
post #14907 of 15633
Quote:
Originally Posted by BigSteve82 View Post

I've been looking for a solution to this as well for a long time and have yet to find one. When I posted here and over in the 3D thread for this set, most people said they could never see what I was referring to when I talked about the "red tint" when 3D is enabled. Most thought I referred to the red ghosting when you watch 3D and the input is named to anything but "PC" (which it is SUPPOSED to be named to for 3D, btw).

I'm glad there is someone else inquiring about the same thing and I'd love for there to be an easy solution that someone has found since my last visit to the forums. While I can barely notice the red tint anymore while wearing the glasses, I can't help but think the 3D picture would look even better if it could some how be disabled.

For anyone wondering, this is what we're referring to:
---clipped----

Thanks for posting this. I have to believe that since these TVs have a VESA 3d Sync port, that there has to be some way to shut this off DLP link since it is no longer beneficial. If I figure it out, I'll post it.

I did want to share a discovery today.. If you switch "PC Mode Ident." from "Auto" to "Enabled" in the service menu ("Option Byte"), you no longer need to name your Source 3 as PC. I changed mine back to Blu-ray.

Quote:
Originally Posted by PaulGo View Post

I don't believe the red tint in the 3D mode can be disabled. The red tint is a lot less when you wear 3D glasses (with an emitter) and I believe eliminated when you use DLP link glasses.

This is true... but when using an emitter there is still a little bit of red showing through... I think this is because DLP link does this: "left eye, right eye, left eye, right eye, sync" --- "left eye, right eye, left eye, right eye, sync" --- "left eye, right eye, left eye, right eye, sync". I think the sync must be an entirely red screen. Just a guess though.


Unfortunately it looks like this is a Samsung issue.. The Mitsubishi sets with the same TI chip have the option to disable: http://www.shopnbc.com/images/cc/pdf...th%20XPAND.pdf
post #14908 of 15633
BTW: This should probably be added to the FAQ... An assessment of 3d glasses with Samsung DLPs.
post #14909 of 15633
Got the "check fan 1" message than the TV shut down. Anyone know the part number for fan 1?
post #14910 of 15633
Quote:
Originally Posted by NetCoder View Post

I did want to share a discovery today.. If you switch "PC Mode Ident." from "Auto" to "Enabled" in the service menu ("Option Byte"), you no longer need to name your Source 3 as PC. I changed mine back to Blu-ray.

Thanks for that info, going to change mine right now.

And yes, unfortunately I think we are stuck with the red tint issue. My parents have a Mits, and DLP-Link can be turned off, thus eliminating the red tint. So for us, it's best to stick with DLP-Link glasses, as it gets rid of most of it.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Rear Projection Units
AVS › AVS Forum › Display Devices › Rear Projection Units › 2008 Samsung HL61A750 LED DLP owners thread and FAQ