2008 Samsung HL61A750 LED DLP owners thread and FAQ - Page 530 - AVS Forum
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post #15871 of 15886 Old 12-11-2014, 06:25 PM
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intermittent loud buzzing

Hi,

I've had a HL61A750 since 2008 and have loved every minute of it. The only part I've ever replaced was a small fan a little over a year ago.

Over the past two days I have experienced an intermittent loud buzzing & pause at random points. This has happened when watching content from two different HDMI sources. The buzz lasts from a tenth of a second to two seconds, and just happened about 6 times during a one hour show. The audio is running out the the stereo outs, to a receiver. When it buzzes, the picture pauses as well. I'm hoping there is something I can do to keep my very first big screen alive.

Thanks for the help!!!
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post #15872 of 15886 Old 12-11-2014, 07:37 PM
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Quote:
Originally Posted by Stucco View Post
... Over the past two days I have experienced an intermittent loud buzzing & pause at random points...
My WAG: a capacitor on the main smps is going bad. Check the main smps (mounted on top of the main board housing) for any stand-up aluminum caps that show any sign of bulging on top.
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post #15873 of 15886 Old 12-12-2014, 07:55 PM
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Originally Posted by evilpaul View Post
Hi all, first time posting here but I've uses a lot of info in this post in the 5 years I've had this TV so thanks for everyone who contributed. I love this freaking TV!

Now on to the bad, a few months ago I got a few black and white spots but now it is a ton(pic below). I've gone through a lot of the pages and I think I have the info on what I need and how to do it but wanted to double check. I believe I just need to order this http://www.shopjimmy.com/samsung-mit...7-dlp-chip.htm but is there anything I should double check to make sure this will fix the issue? I've had no other issues and it still works fine except for the dots. Thanks in advance for the help.
thats where i got my dmd from just a couple weeks ago. good to go now!

on that note....thanks to cosmicvoid and others, i ordered chipset heatsinks for the inductors in the LED Driver module. I used Arctic Silver Thermal Adhesive to attach them. Not seen here in the pics is a narrow strip of aluminum that "connects" them all together. That way...if one of the inductors comes loose again (which it had better not....) it won't fall and short anything out.

I thank everyone that helped me save this fine TV. It was easier than I thought. Still glad I bought that rework station....made soldering/desoldering things a LOT easier.

Anyway....for the heatsinks.........






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post #15874 of 15886 Old 12-12-2014, 07:58 PM
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Quote:
Originally Posted by cosmicvoid View Post
My WAG: a capacitor on the main smps is going bad. Check the main smps (mounted on top of the main board housing) for any stand-up aluminum caps that show any sign of bulging on top.

yep....and I'd check ALL your caps. I'd bet that the 4 2200uf ones on your PS board are bad. You have it open....might as well replace them all.
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post #15875 of 15886 Old 12-12-2014, 08:19 PM
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Originally Posted by tribbler View Post
... Anyway....for the heatsinks...
Well, that's a method I hadn't thought of. Probably easier than trying to find an extrusion of the right size. Guess you won't have those inductors overheat any more .
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post #15876 of 15886 Old 12-17-2014, 10:02 AM
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Re LED Brightness controls.
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Originally Posted by agentrnge View Post
on my old set it seems stuck effectively on MAX regardless of the setting. Now that I can compare mine and the other set, I realize this has never worked on my original set that I can recall. The new set shows obvious differences between Low and Max.
...
I'll try re-applying the 2008 firmware update and maybe a factory reset.

I have tried on two different HDMI inputs. TV is in Movie mode normally, pretty much defaults on everything AFAIK. Not sure if there is certain screen modes that disable the functionality of the LED brightness adjustment.

Any ideas?
]
I went through all the user mode settings, tried turning dynamic things on and off, game mode on and off, no matter what I do the LED controls do not work.

I did a factory reset. It made no difference. I have not tried re-applying firmware yet. Anything else anyone can think of checking?

I went through service mode with some docs from other people's calibration. I didn't really change anything, just observed that all my values seemed to be within reasonably close values of others' TVs. I did not see anything about LED controls. I don't have actual calibration equipment to set levels/sensor setup in the service menu. I'm not sure if that is what is needed. I would think regardless of calibration, LED output level should still be adjustable within the user menu.

Thanks everyone.
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post #15877 of 15886 Old 12-17-2014, 10:04 AM
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Quote:
Originally Posted by tribbler View Post
I thank everyone that helped me save this fine TV. It was easier than I thought. Still glad I bought that rework station....made soldering/desoldering things a LOT easier.

Anyway....for the heatsinks.........
Those heatsinks are looking nice and shiny. Good stuff! Should be good to go for a while.
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post #15878 of 15886 Old 12-17-2014, 10:48 AM
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Every time I turn off the TV say to go dinner with the wife and when we get back home and I go to turn the TV on I get the "Mode Not Supported" message. Takes like 4 to 5 times turning off the TV, pre/pro & Directv unit to finally to get it to work. Anyone else been having this issues ? This all started about 2 months age. I do have the Directv unto set to output 1080i only

Thanks
Randy

Last edited by Redneck_Randy; 12-17-2014 at 11:00 AM.
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post #15879 of 15886 Old 12-17-2014, 12:34 PM
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Quote:
Originally Posted by agentrnge View Post
Re LED Brightness controls.


I went through all the user mode settings, tried turning dynamic things on and off, game mode on and off, no matter what I do the LED controls do not work.

I did a factory reset. It made no difference. I have not tried re-applying firmware yet. Anything else anyone can think of checking?

I went through service mode with some docs from other people's calibration. I didn't really change anything, just observed that all my values seemed to be within reasonably close values of others' TVs. I did not see anything about LED controls. I don't have actual calibration equipment to set levels/sensor setup in the service menu. I'm not sure if that is what is needed. I would think regardless of calibration, LED output level should still be adjustable within the user menu.

Thanks everyone.
You ARE using the Contrast control, correct? The Brightness control adjusts the Black Level of the picture.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
 
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post #15880 of 15886 Old 12-17-2014, 12:43 PM
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Quote:
Originally Posted by Augerhandle View Post
You ARE using the Contrast control, correct? The Brightness control adjusts the Black Level of the picture.
No, I am talking about the LED level control in Detailed Setting. Not brightness or contrast. Brightness and contrast controls work as expected.

My understanding of brightness/contrast is actually adjusting how much light the DLP chip will reflect and basic black/white levels. While LED control level sets the power output level of the LEDs (regardless of black level/contrast/brightness/image content)

http://www.manualslib.com/manual/361...page=25#manual
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post #15881 of 15886 Old 12-17-2014, 07:06 PM
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I've owned this TV since it was first released in early 2008 and it's been fantastic until it started having issues this year. It had the white dot issue back in March of this year and I had the TV serviced (replaced the DMD chip with a new one). Worked as good as new until this week where a random white dot has come back on the screen

What could it be this time? Is it the DMD again? Already dropped $330 for that repair, not sure I want to do that again.
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post #15882 of 15886 Old 12-17-2014, 08:20 PM
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Quote:
Originally Posted by danondorf View Post
... What could it be this time? Is it the DMD again? ...
The DMD is the only thing that will cause the 'white dot' syndrome. If you did the replacement yourself, it would cost you less than $200.

I remember reading, that at some point, TI had a bad lot of DMDs that had short lifetimes, but that must have been a couple years ago, so doesn't seem too likely you got a bum chip.

One other idea comes to mind: maybe the replacement chip was installed with inadequate heat sinking. The original thin foam thermal material was not the best material in the first place, and if someone tried to reuse it with the new chip, the thermal conductivity is probably poor. Arctic Silver is the way to go.
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post #15883 of 15886 Old 12-18-2014, 07:37 AM
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danondorf: Just the DMD parts alone might have some warranty, if not the service itself. Unfortunately probably something like 6 months. I know when I bought my chip, there was a 1 or 2 year warranty option ( I declined ).

When we service our own sets we usually spend a good amount of time cleaning the fans and heatsinks thoroughly. As well as replacing heat sink paste/pads with Arctic Silver as cosmicvoid mentioned. Did the service include a cleaning while they were in there? If not the heatsinks might just be choked with dust and causing more parts, even the new one, to heat-soak and fail faster. If the old thermal pad on the DMD heatsink was re-used that could be a bargaining chip to fight for a replacement from the people who did the service. I don't know how you know if it was or wasn't though.

Its down to ~$180 for the DMD last time I checked.
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post #15884 of 15886 Old 12-19-2014, 04:37 PM
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Quote:
Originally Posted by agentrnge View Post
danondorf: Just the DMD parts alone might have some warranty, if not the service itself. Unfortunately probably something like 6 months. I know when I bought my chip, there was a 1 or 2 year warranty option ( I declined ).

When we service our own sets we usually spend a good amount of time cleaning the fans and heatsinks thoroughly. As well as replacing heat sink paste/pads with Arctic Silver as cosmicvoid mentioned. Did the service include a cleaning while they were in there? If not the heatsinks might just be choked with dust and causing more parts, even the new one, to heat-soak and fail faster. If the old thermal pad on the DMD heatsink was re-used that could be a bargaining chip to fight for a replacement from the people who did the service. I don't know how you know if it was or wasn't though.

Its down to ~$180 for the DMD last time I checked.
My replacement DMD was $185. Not sure how many he has left.

I will further support the use of Arctic Silver. It is a must.

And as agentrnge said....a good cleaning while everything is open is a must.

I even replaced some bad capacitors as well.
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post #15885 of 15886 Old 12-21-2014, 03:42 AM
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Quote:
Originally Posted by agentrnge View Post
danondorf: Just the DMD parts alone might have some warranty, if not the service itself. Unfortunately probably something like 6 months. I know when I bought my chip, there was a 1 or 2 year warranty option ( I declined ).

When we service our own sets we usually spend a good amount of time cleaning the fans and heatsinks thoroughly. As well as replacing heat sink paste/pads with Arctic Silver as cosmicvoid mentioned. Did the service include a cleaning while they were in there? If not the heatsinks might just be choked with dust and causing more parts, even the new one, to heat-soak and fail faster. If the old thermal pad on the DMD heatsink was re-used that could be a bargaining chip to fight for a replacement from the people who did the service. I don't know how you know if it was or wasn't though.

Its down to ~$180 for the DMD last time I checked.
Thank you all. I hadn't thought of that - how can I check to see if it was re-used? They are supposed to call me back to see if the DMD parts are still under warranty (they told me it was unlikely and had to contact to Samsung on it). I've been out looking at TV's for the first time well, since I purchased this one and boy things have changed.

I was maybe considering selling this one and using the money toward a new set, but everything is a Smart TV, doesn't have 3D, or other issues I've heard of (flashlighting effect). How do new LED sets compared to this set? Can you still get away with getting 120hz on a modern 2014 set and have comparable performance to this set?
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post #15886 of 15886 Old Today, 08:05 AM
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Quote:
Originally Posted by danondorf View Post
how can I check to see if it was re-used?
...
but everything is a Smart TV, doesn't have 3D, or other issues I've heard of (flashlighting effect). How do new LED sets compared to this set? Can you still get away with getting 120hz on a modern 2014 set and have comparable performance to this set?
If you took it apart and saw a thermal pad that would most likely be the original. Its not *that* bad in reality. It has worked well enough to transfer heat in most sets for years without issue. When I had mine apart and felt the pad on the heatsink, it was cold to the touch. It felt as though it had about as much thermal conductivty as the heat sink metal itself. I almost re-used it on my 2nd set it felt decent enough. On my first set it was a lower quality pad. That did not feel cold to the touch. I dont know if there were revisions/updates. The 2nd set I just picked up as made about a year after my original set.

As far as new TVs go.


All this fast motion badly interpolated frame garbage drives me nuts. Most people seem to love it because they were told faster is better. So TV mfrs are all about it. Gimmicks like curved screens to make the picture look perfect ( for one person in the exact right spot ). I guess boasting accurate colors and levels would be a dumb thing to have in a TV. So lets just make everything brighter than the sun, and make 24p content look like a hidden camera documentary about a soap opera.
</rant>
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