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The NAD T775/T785 AVRs w/ HDMI 1.3 Thread! - Page 142

post #4231 of 4288
Quote:
Originally Posted by elmachin View Post

I took the Video board out and I noticed that 4 resistors were reworked, and they looked awful. The image is 2 of the 4.

I re soldered the 4 resistors and cleaned up the flux. Now everything is fine. I ran it over night with no issues! I did find a service manual online and the resistor values don't match? And, usually when resistors are changed the board will be up-reved like 1.1 or 1.0A my board still says 1.0. My volume knob was replaced under warranty 5 years ago. I don't know if the resistor changes were from the factory or happened at the same time as the volume update.

RES Schematic Parts List installed
R82 2k 750 750
R83 2K 1.5k 1.5k
R16 0 47 0
R24 0 22 0


If this was a factory board then it is bad! You might want to mention it to NAD. It is probably a QA miss.
post #4232 of 4288
The NAD authoized service person I used to service my unit under warranty said the installed values are correct according to what he called a running change.

NAD obviously has some issues if the schematic and parts lists don't match. Whoever did the resistor change whether it was the factory or under service should mark the board with some revision status so that the next person who looks at the board can tell what changes have been made.

Now that I have looked over the board in depth I wish I could see a good picture or service manual for the VM100 and VM150 so that I could see the differences. From a web image I noticed they switched to an Altera part in the VM150 instead of the Xilinx CPLD on my board.

Here's a picture of my video board for posterity.

post #4233 of 4288
Quote:
Originally Posted by elmachin View Post

The NAD authoized service person I used to service my unit under warranty said the installed values are correct according to what he called a running change.

NAD obviously has some issues if the schematic and parts lists don't match. Whoever did the resistor change whether it was the factory or under service should mark the board with some revision status so that the next person who looks at the board can tell what changes have been made.

Early in this thread owners had problems with the receivers accepting multi-channel LPCM. There were component level changes made by dealers or service centers on the HDMI board for the batch that had already been sold (meanwhile the factory made changes for future units). Perhaps you have one of those early examples.
post #4234 of 4288
I spoke too soon. I did all my testing with the cover off.

Last night I put the cover back on and left it running all night. In the morning there was no audio. I changed the source to another input and then back to the original and the audio returned. I listened and after a few minutes the audio would cut-out for a split second and over time the cut-out would last longer and longer. I tried HDMI 1 which only has one internal switch before going into the AD9388 video decoder rather than HDMI 2 which goes through 2 switches before going into the AD9388.

Also, last night once it flashed white noise on the video screen, but did not return as bad as before.

I've never had audio issues before when using coax or optical. Unfortunately, my new device only has an HDMI output.

I don't think I'm loosing sync? When you loose HDMI sync the HDMI on the NAD screen will flash right?

Is there a service mode, self check or something that can be used for diagnosis or do I need to solder wires on the board and get out my oscope?

Matt
post #4235 of 4288
Do the other hdmi ports also act the same way if left running over nite?
Is this new device the only hdmi source you have? Can I ask what is it (not that it should matter).

I assume the fans are running ok? Leave off all nite and then turn it on (so the unit is cool), how long before it\
starts acting up? The fact that it ran ok with the cover off makes it sound like it's overheating when the cover Is on.
post #4236 of 4288
Quote:
Originally Posted by Phil Tomaskovic View Post

Do the other hdmi ports also act the same way if left running over nite?
Is this new device the only hdmi source you have? Can I ask what is it (not that it should matter).

I assume the fans are running ok? Leave off all nite and then turn it on (so the unit is cool), how long before it\
starts acting up? The fact that it ran ok with the cover off makes it sound like it's overheating when the cover Is on.

Yes, the other ports do the same thing and the new source (roku3) and my bluray player both have the audio dropout problem.

It definitely gets worse as it warms up. The fans are fine, but they aren't even designed to produce air flow in that section of the T785. The HDMI/audio card section of the chassis is in the corner without any external air vents or way for air to pass through. I would assume this means that they don't think that overheating will ever be a problem.

In the service manual there are a bunch of waveforms/test points. I soldered wires on all the HDMI board test points (which is why I left the cover off for so long), but when no issues happened I removed them and closed everything.

I am going to put the wires back on today and make them long enough to exit the chassis with the cover attached.

If I can't find anything with the measurements I'm going to use freeze spray to see if cooling one of the ic's makes a difference. If all else fails I guess I could cut some vents in the cover and add a fan.
post #4237 of 4288
You could try to glue a heat sink on top of the ic using heat conducting glue. You can use the type used for ram circuits or for old cpu or gpu.
post #4238 of 4288
Quote:
Originally Posted by roadrunnerdk View Post

You could try to glue a heat sink on top of the ic using heat conducting glue. You can use the type used for ram circuits or for old cpu or gpu.

I like the heatsink idea.

I actually purchased some new hdmi cables and that seems to have solved the video (snow/static) issues, but I am still getting audio drop-outs I am using 6' cables. I don't think I'm loosing sync? doesn't the hdmi flash on the display when that happens?
post #4239 of 4288
I do not think you are loosing sync - if you are the unit will 'unlock' the decoding it is doing and the small relays will click and display will change from DTS or whatever it was decoding. I think you have a problem with heat building up in the unit.
post #4240 of 4288
I am still waiting for my T775HD to be fixed. It is at ProAudio Electronics in Tampa. They said they ordered a new Amp module and are waiting for it. I sent the receiver to them for the second time on July 18th. I have been without it working since end of May! This is taking a loooooong time. I would be totally nuts if I did not have a spare (T763).
post #4241 of 4288
I finally got my T775HD back from ProAudio Electronics in Tampa. They said they have replaced the amp board. I have tested it and all channels work now. I have not run Audyssey calibration yet because I wanted to make sure it sounds great first without any of the DSP. Without even using an SPL meter, I just used all the channel level values from my T763 to program my T775. It sounds ok except in 7.1 analog input mode, the sub was too hot. I had to turn it down. The T763 sounded a lot tighter in the sub compared to the T775HD. I wish it was easy for me to do an AB comparison easily. I will spend some more time with it this weekend to see how it behaves. I have gotten to appreciate the awesome analog outputs in my Sony S5000ES bluray player with my T763 while my T775HD was in the shop. I have wired it up again with analog for my T775HD also (in addition to the HDMI).
post #4242 of 4288
Bommai,

Glad to here you got your T775 back and so far no glitches to speak of.
Quote:
Originally Posted by bommai View Post

I have gotten to appreciate the awesome analog outputs in my Sony S5000ES bluray player with my T763 while my T775HD was in the shop. I have wired it up again with analog for my T775HD also (in addition to the HDMI).

With both 7.1 analog and HDMI hooked up from the same BD player, do you here a slight hum emitting from your speakers. When I originally got my T175HD, I hooked up my Oppo BDP83 in the same manner and no matter what I did, I could not get rid of that nasty hum. It was really only audible during low level listening but once I heard it, I always heard it. I removed the analog multichannel RCA's(hum gone) and am just using HDMI for BD playback and SACD's. I listen to CD's with my Cambridge Audio 840C player and use it's analog section because of it's superior onboard DACs.

Bill
post #4243 of 4288
Hello,

I'm new at this forum and hope you guys can help me. I own the first version of the T785 and trying to control it with the NAD app. I can make the connection, but the app tells me firmware is to old. Can someone send me the latest firmware for the T785? I'm still using the original from 2008.
You can send it to marcodebruijne@yahoo.com

Thanks
post #4244 of 4288
Contact Michael Alguire (malguire@lenbrook.com) for firmware upgrades. Be aware that you should furnish your AVR's serial number and current firmware version (obtainable by pressing the left and right source buttons simultaneously on the front panel). You should also be familiar with computer serial connections as you need to connect a computer's serial (RS232) port to the NAD's serial port via a null modem cable).

If you don't feel comfortable performing firmware upgrades yourself (remember, there's always the chance the upgrade could screw up the AVR if something goes wrong), contact an authorized dealer.
post #4245 of 4288
I have searched this giant thread and did not see a fix for this. Sorry if this was covered and I missed it.

I have a T775HD2 that I purchased back in July 2011. It sat in the box for over a year till my basement was done. I set it up last summer but I did not really use it till recently.

The problem is it shuts itself off when the volume is turned up to a loud level to watch an action movie.
The only way to restart it is to unplug the unit and it will then turn back on. For some reason the volume on the Blu Ray player will go higher than the cable box and that’s when it mostly shuts off.
I have this set up in a giant basement so I need the sound level to really crank to fill the space.
Any thoughts?

Also when the audyssey is turned on the max volume is only loud enough for a normal TV show. I have to turn the audyssey off for movies.

NAD T775HD2
Dyn Audio Focus 200 center
Dyn Audio Focus 220 front
Klipsch SW112 sub (2 units)
B&W CCM683 rear in ceiling
All plugged into a Furman IT-Reference15i power conditioner
post #4246 of 4288
  • Try plugging it directly without the power conditioner. May be the power conditioner does not handle the additional power requirement at higher volume.
  • Is your cabinet well ventilated? Are the fans in the receiver working properly?
  • Try upgrading to the latest firmware. If you are in the US, you can call NAD salon and they will generally email a link to download the firmware. You need a straight through 9-pin serial cable and a Windows PC to upgrade. You will need a fully compatible USB to serial adapter if your PC does not have a serial port.
  • Are you talking about Audyssey dynamic volume or Audyssey room correction itself? I don't use dynamic volume at all. I use Dynamic EQ and I use the NAD curve for Audyssey. Also make sure when you calibrated, you got reasonable readings. Make sure it did not set your sub level to -12dB because if it did that means your sub was too high. You will have to reduce the gain on the sub and rerun audyssey.
  • If you bought yours through certain credit card (such as Amex), they extend warranty to an additional year. So, you should be able to take advantage of it.
post #4247 of 4288
Quote:
Originally Posted by Willland View Post

Bommai,

Glad to here you got your T775 back and so far no glitches to speak of.
With both 7.1 analog and HDMI hooked up from the same BD player, do you here a slight hum emitting from your speakers. When I originally got my T175HD, I hooked up my Oppo BDP83 in the same manner and no matter what I did, I could not get rid of that nasty hum. It was really only audible during low level listening but once I heard it, I always heard it. I removed the analog multichannel RCA's(hum gone) and am just using HDMI for BD playback and SACD's. I listen to CD's with my Cambridge Audio 840C player and use it's analog section because of it's superior onboard DACs.

Bill

Sorry for the late reply. I hear a faint hum even when I am playing something on the PS3 (connected only through HDMI). I do have multi channel analog hooked up to my Sony S5000ES bluray player (in addition to HDMI). Does not really bother me though..
post #4248 of 4288
Does anyone know the make and model number(s) of the cooling fans in a t785HD? I have one that's getting noisy and I'd rather have the parts on hand when I pull the receiver out so I don't have to go through the process twice.
post #4249 of 4288
Quote:
Originally Posted by cctvtech View Post

Does anyone know the make and model number(s) of the cooling fans in a t785HD? I have one that's getting noisy and I'd rather have the parts on hand when I pull the receiver out so I don't have to go through the process twice.
NAD recommends lubricating the fans with sewing machine oil or something like that. A small dab on each fan quiets things down Check with tech support at NAD (Bob Moran) for a quick instructional.
post #4250 of 4288
Quote:
Originally Posted by ddingle View Post

NAD recommends lubricating the fans with sewing machine oil or something like that. A small dab on each fan quiets things down Check with tech support at NAD (Bob Moran) for a quick instructional.
Oil? HAH!

As my name suggests, I am a tech by trade. In my experience, attempts to re-lubricate cooling fans are stopgaps at best. Typical cooling fans use sintered metal bushings that tend to score and wear with age or ball bearings that develop flat spots and/or scoring. Once the metal is scored or out of round, added lubricant is quickly ejected from the bearing leaving the fan unlubricated and noisy. The only long term cure is to replace the fan.

My t785 is installed in a cabinet which, although it allows sufficient cooling, makes it difficult to remove and reinstall the AVR. The t785 is also a heavy beast. I would prefer to do this once.
post #4251 of 4288
cctv - I had the fan problem as well. My tech replaced them with the newer fans (the ones that come in the 787 models, I believe). They are quieter and, apparently, less prone to defects.
post #4252 of 4288
dylan24, I know I can remove the t785 and take it to a tech but then I'll be without it for some period of time. That would make it difficult to watch TV or even access my HTPC, where I'm typing right now. My preference would be to obtain the fans and replace them myself.

I have started a support ticket at NAD and we'll see where that goes.
Edited by cctvtech - 11/3/13 at 9:09am
post #4253 of 4288
Quote:
Originally Posted by cctvtech View Post

dylan24, I know I can remove the t785 and take it to a tech but then I'll be without it for some period of time. That would make it difficult to watch TV or even access my HTPC, where I'm typing right now. My preference would be to obtain the fans and replace them myself.

I have started a support ticket at NAD and we'll see where that goes.

I recently replaced the fans on my T775 a couple of months ago because several of them were starting to buzz and make noise frequently. Since my T775 was out of warranty, I figured it could not be much harder to replace them than replacing case fans in a PC...and that was about right. After removing them, I tried to locate the same brand but they are not commonly available anywhere online for reasonable prices (likely an older model that has been replaced), so I went instead with fans with similar RPM and lower db ratings. The trick was that the typical case fan in that size is thicker than will fit in the housing on the bottom of the T77x series. The original fans in the unit were 20mm thick, but most common case fans in the same size (60mm x 60mm, I think) are 25mm thick. I went with some that were 15mm thick.

The housing that holds that fans can be easily removed from the bottom of the receiver case by removing the screws that hold in the plate with the fan shields. There are five fans and all of them have their power cables plugged into a bank of pin connectors accessible from the top side of the case (once the whole case cover has been removed). The other thing I found was the special screws used in the original fans likely will not work with most off the shelf case fans and I had to use other screws to hold the new fans in. You need to pay attention as to how to wrap the power cables around the edge of the fans so they will not get in the way when putting the housing back with the plate on the bottom of the T77x case, but if you are careful it is not too hard. Most common PC case fans have a 3-pin connector and the T77x has 2-pin connectors, so I also bought adapter plugs (they were 2" length wires with a 2-pin female connector on one end and a 3-pin male connector on the other end).

Needing the adapters and new screws delayed the process a bit compared to if I had everything up front, but the fans and adapters were available online at the best price and the screws came from the local hardware store. Total cost...about $30 plus my labor.

These are the type of 3-pin to 2-pin adapters I bought that match the power pin sockets in the T77x. (I got the "D" version of these adapters.) And these are the fans I used.

One caveat....this was for a T77x model. I do not know if the T77xHD models use the same size fans or not.
Edited by NCCaniac - 11/3/13 at 4:29pm
post #4254 of 4288
NAD answered my support request by referring me to Lenbrook. As usual, Lenbrook was very responsive. I ordered 5 fans and 20 screws today.

Fans: Part Number 0821000020-902000 - $12.50 each (very reasonable) (5 total).
Screws: Part Number 0180000301038-9021000 - $.38 each (also reasonable) (20 total, 4 for each fan).

The only cost that was a bit high was shipping from Canada to the U.S. ($20.00). All in all, still very reasonable for OEM parts and very worthwhile, all things considered.
post #4255 of 4288
Hi all,

I own a T785 with the AM200 and VM150 MDC cards installed. Running Firmware 1.36 AFAIK.


I have a Dune HD Max network player connected to it, as my only HDMI input device. My TV is a Samsung Plasma 51" Euro model is Called D8000.

My problem is that I experience screen flickering all the time. Flickering occurs during playback and menu browsing, there is no real "recipe" to trigger it, it's just there, all the time frown.gif

I lasts about 2 seconds at a time, and starts with 0.5 seconds of black screen, then turns into 0.5 seconds of snow/static noise, then 0.5 seconds of black screen AND returns to normal. My TV seems to loose the input or something, as the OSD lights up every time the flickering occurs.

I've tried everything that come to mind, fx.

* Disabling any bi-directional communication such as HDMI-CEC and Anynet+, etc.
* Set color depth to 8-bit on the Dune player
* Set color depth to 12-bit on the Dune player
* Checked network connectivity, no issues. 100Mbit/s can be saturated to my Dune Player
* Playback of local media, direct from built-in harddrive. Same issue.
* Tried a new set of HDMI cables

For now, I still need to test whether it's the Dune player or the T785 causing the issues. But I'm just putting the word out there, to check if anyone else has seen, or IS seeing these similar issues??


All replies and tips/pointers appreciated.

/Jim
post #4256 of 4288
-> Jim, how long cables do you use. I've seen cases where using short cables could cause such problems. I think you should use cables no shorter than 1 m.
post #4257 of 4288
I had the same problem with short cables. Once I went with 3 feet, it was fine. I had a two feet cable that gave me trouble.
post #4258 of 4288
Quote:
Originally Posted by bommai View Post

I had the same problem with short cables. Once I went with 3 feet, it was fine. I had a two feet cable that gave me trouble.

Quote:
Originally Posted by roadrunnerdk View Post

-> Jim, how long cables do you use. I've seen cases where using short cables could cause such problems. I think you should use cables no shorter than 1 m.

Much obliged, guys. I'll try using longer cables. Will report back smile.gif

BR Jim
post #4259 of 4288
Quote:
Originally Posted by itdk View Post


Much obliged, guys. I'll try using longer cables. Will report back smile.gif

BR Jim


Switched to a 2 meter cable, problem is gone. Thanks for your help.

/Jim
post #4260 of 4288
I have a T787 and I am really happy with it. Great sound and it's become the center of my HT.
I would really like to invite to a little brain storming around what we would like to get added to the MDC cards.
Personally I have the following connections: Denon 3930 - >HDMI (DVD), Oppo BDP83SE -> HDMI and 2ch analogue (BR, CD, SACD, DVD-Audio), Radio (DAB, FM and Internet radio) -> Coax, PC -> USB -> Wyred4Sound DAC2 -> 2 ch Analogue, TV decoder -> HDMI (video) and optical (Sound)

Currently I have my Wyred4Sound DAC-2 for upgrade to the DAC2DSDse. Hopefully this will be a worthwhile upgrade. Time will show.
In the meantime I have connected my PC via HDMI to the T787.
I use Foobar and need to resample to 44.1 kHz to be be able to use WASAPI in Foobar for the receiver to play all the different 16/24 bit FLACs I have ( 44.1, 48, 88.2, 96, 176.4, 192).
I also play SACD-R ISO's and it works perfect execept that it's resampled to 44.1 kHz.
I would also think it should be possible to play Surround music this way. Currently my PC is too slow as it needs to also do the resampling.
Attached is a Loewe 42" Modus TV and Dali Suite 2.8 (FL/FR), Suite 0.8 (C) and B&W M1 (SR/SL) speakers.

The T787 is a monster of a receiver . I really like it a lot and it's just a shame there is no USB connection available.
I am currently building up all my music on a Synology NAS in my basement. My "music" PC is close to the T787 and also W4S DAC2, but I am absolutly convinced that the T787 should be able to do all the tasks of an external DAC.
Just like the Pioneer SC-79 9.1 A/V Receiver.

We need to push NAD in the direction to include USB connection to a PC / Mac. Why should we need an external DAC? It's a costly receiver anyway.

Would anyone know anything about what NAD is planning for the MDCs upgrade path?

Any thoughts?
Edited by fiske - 11/21/13 at 10:39pm
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