Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not availabl

[k2skaterii]

I am having the same problem as the BigJim42, in the thread linked below. I did not want to Hijack his thread so I am starting my own. Hopefully I’ll be able figure out what the problem is, and maybe the solution I find will help BigJim42. Jim I hope you don’t mind, I’m plagarizing parts of your post that apply here, such as the description of the problem.

https://www.badcaps.net/forum/showth...hlight=dp42647

BigJim42 was able to find a link to the service manual for this TV, thank you! Here’s the link.

http://www.mediafire.com/?mznqztw3ihm

Sanyo DP42647 chassis no: P42647-00, assembled JULY 2007 in Mexico. Unfortunately the TV belongs to a friend I am trying to help out. Which means I don’t know exactly what was being done when the TV stopped working, how how it failed, or anything useful like that... All I know is that it used to work, and it does not work now.
Its been sitting unpluged and not working for several months. Much like BigJim’s Box, leaving it upluged didn’t help out at all. When first plugged in, there are no standby or power indicator lights. Pressing the power button on the side of the set causes the green indicator light on botton right front of set to turn on. I don’t have the remote, but I would assume that the remote would be able to turn the set on as well. I am able to cycle set "On" and "Off" with remote or keypad. I do not see any backlight at all, and am not able to detect any image by shining a bright light at front of set.

I have opened case and inspected all boards for visible flaws. Nothing on the boards look damaged, or fried, or burnt or anything… It all looks decent.

I didn’t do much, well any testing of voltages on the power supply or the main board. I did unplug the connections on the main board one at a time, trying to produce a different output from the TV. I was able to get the LCD’s backlight to come on by disconnecting the 4 pin plug that is plugged in to the “K6R” plug on the main board. The “K6R” links to the “CN2” on the control board. P.47 on the sevice manual shows the “PC Board Connections and Locations” relating to “K6R” and “CN2”. On P.49 the “K6R” plug’s pins are defined as “BL_ADJ1, BL_ON, BL_ADJ2, and SELECT”. I’m going to assume that the “BL_****” is refeering to the back light and that th”K6R” plug tells the back light to either turn on or off, and that’s why when it was disconnected the backlight turned on. When BigJim42 did this he got a variety of vertical lines on his screen, I am experiencing the same vertical lines on my set.

Using some sort of logic that made sense at the time…. I figured that the symptoms I was experiencing were being caused by a fault on the main board… That’s when I ordered a new main board. Unfortunately the issue still existed after the new main board was installed, so I am now out the $80 for the main board.

Now I am thinking that there is probably an issue with the control board, or maybe the power board. And this is where I am running into a wall, because I don’t know where to go from here or how I can figure out which board is actually the problem. Any help would be greatly appreciated.

Thanks!
Ken

[BigJim42]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Ken, I purchase a used inverter board off of eBay and swapping it out did not improve things. I did a lot of probing all over my board checking voltages, and did not really find any problems, except one which I may have caused myself.

tom66 wrote to me, "Have you checked the DC input to the T-con board? If that is low, you may see that effect."

It has been a while since I've looked at the project. I did find one blown component on the main board. A very tiny inductor. I'm not home now, but can probably identify which component it is if that is helpful to you. I think I may have blown the inductor by shorting two pins together when I was checking voltages on one of the ICs on the main board. Do you know what hindsight is? I found some strange voltages, looked hard at the board and found the blown away chip the size of a grain of rice. At that point, I recalled that my meter probe has slipped and shorted between two pins on the side of a chip that probably had twenty pins. When you know something has fried, your sense of smell is heightened, and you remember that "burnt electrical smell."

That was a discouraging moment in the repair process. Am I making things worse in the process of attempting repair? I also was discouraged because I'd say I was 25% sure that the repair manual I was using did not really match the TV I was working on.

Ken, I appreciate you letting me know you are working on a similar project. Please let me know if you get it working. If it's not the power supply, not the main board, or the inverter, then does that mean it must be the T-Con board, or LCD panel itself?

If you fix yours with a new TCon board, then perhaps I'll try to repair the fried inductor on my main circuit board.

Good luck to you, Jim.

[k2skaterii]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Ken, I purchase a used inverter board off of eBay and swapping it out did not improve things. I did a lot of probing all over my board checking voltages, and did not really find any problems, except one which I may have caused myself.

Thanks, you just saved me $50. I was going to purchase an inverter board tomorrow.

tom66 wrote to me, "Have you checked the DC input to the T-con board? If that is low, you may see that effect."

I just checked the DC input to the T-Con board, I think. According to P51 of the service manual, the cable to goes up to the TCon board is the 30 Pin K5LV plug. I tested the VIN_12V point on the Tcon Board which is right above where the cable plugs in, I got a reading of 11.82V, that should be close enough for gov't work.
I also tested the K5LV_19, which I think should be 3.3V, but it only tested at 1.38V, so thats more than a little bit low (I think). Honestly I dont know what to make of that low reading on K5LV_19. Since there is a resistor on the schematic between the "3.3 V" label and where I am testing. It could be working just fine! When it comes to reading wiring diagrams I know enough to be dangerous.

I feel your pain when it comes to making mistakes, I call them “learning experiences”. But I know one thing about those learning experiences, you dont make the same mistake again! Learning the hard way is cheaper than paying for lectures and formal classes!

Hopefully someone out here can point us in the right direction before I toss any more money at this TV.

[BigJim42]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Ken, have you studied "2 seconds to black?"

https://www.badcaps.net/forum/showthread.php?t=10419

https://www.badcaps.net/forum/showthread.php?t=6724

I believe "2 seconds to black" is a "self protection" mechanism of the main processor board. If it detects an abnormal voltage or system error it shuts down. I don't know the cause, but I believe my TV was experiencing some type of "two-seconds to shut down" symptom. I monitored the line current with an analog meter while the TV starts up. At power on, the current stepped to a high level, and then about two seconds later it dropped back to standby levels.

Please post here in this thread, information about where you bought the mainboard.

I'm curious, do you know if TCon boards are available? I've seen mainboards and inverter boards on eBay. Never looked for TCons though. If they aren't available and the other boards are, then that suggest to me that the TCon boards go bad, and people scrap the TVs and sell the remaining parts.

[BigJim42]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Ken, was the main processor board your bought sold as new or used?

I'll share some pictures of the blown inductor on my mainboard. It was L6172 and is on the lower right corner on the front of the board, near the "tin box tuner" with the antenna connector.

If anyone reading this finds a source for the blown inductor, please add to the post with information on where to buy, and exactly how to specify the part. I have no experience sourcing these tiny components.

<Click on any of the images to see full size.>


Ink pen points to fried inductor L6172.



Above, we see only the solder pads remain of L6172.


Shown below, we see an example of a normal inductor, L6169. It is about 1.5 inches to the right of the blown inductor L6172.

[tw2005]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Don't know anything about these TVs but I'm going to suggest what we are looking at is a fusible link or 0 ohm resistor which has departed this world not an inductor.

[tw2005]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

here's some panasonic data as a guide for metal film. basically dimensions determines the package code. package code determines the wattage.

I'd expect either a shorted board or maybe surge but someone with LCD experience will best guide you.

[attainteddragon]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

im with tw on this one. you are looking at a 0 ohm resistor.

[k2skaterii]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

First I would like to apologize for not posting any pictures... My laptop and phone were stolen a couple of weeks ago. I was using the phone as a camera, which means I am stuck with a loaner phone that takes crap photos.

Ken, have you studied "2 seconds to black?"

I have not yet read those links, but I will tonight.

I'm curious, do you know if TCon boards are available? I've seen mainboards and inverter boards on eBay. Never looked for TCons though. If they aren't available and the other boards are, then that suggest to me that the TCon boards go bad, and people scrap the TVs and sell the remaining parts.

I was hoping someone could tell me if I there is a way to test the T-CON board before I started searching for a new/used replacement. Tri-State-Module has T-Con boards listed, $42+Shipping. But they are out of stock. The product description says vizio, just ignore that little guy...I pulled the T-CON from my set and this is the model that is in my set.

http://www.tristatemodule.com/p-720-...8-dp42647.aspx

Ken, was the main processor board your bought sold as new or used?

I think the board I bought was new. I was planning on getting these folks on the phone and asking them today... Because either they sent me a faulty board, or I need to return a good one and pay for re-stocking fee. I thought I included a link to the board I bought before, but I guess not... Either way here is the link now.

http://www.tristatemodule.com/p-2130...20xw01-v5.aspx

When I call tomorrow I'll find out if they are selling new or used parts, and I'll post the info here.

Don't know anything about these TVs but I'm going to suggest what we are looking at is a fusible link or 0 ohm resistor which has departed this world not an inductor.

TW2005,

On page 15 of the service manual for the set that BigJim and I are both working on says that the "L6172" is Part number "1AV4L2FB3R3MG" with a Description of "INDUCTOR, 3.3U M". The part is listed under the "COILS" section of the parts listing. Unfortunately I am like BigJim, even with the part number out of the service manual I dont know where it can be purchased... Any ideas?

[BigJim42]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Hey Ken (k2skaterii),

Did you see my post above with detailed pictures showing the location of component L6172?

Please do me a favor and take a look at component L6172 (my blown component) on your replacement board and confirm that it is present and not fried like the one on my board. (Report your findings in this thread.) I've said I think I fried the component on my board when the test probe slipped, but who knows, maybe I didn't cause the failure. Maybe the component was fried all along. It is very easy not to notice that it's fried. It is a very small part. Maybe this L6172 is the achilles heal on this board. I spent a very long time inspecting the board looking at it under a magnifying glass trying to find any flaw. I think it took me at least half an hour to find that blown component.

I believe Digi-Key will have the surface mount inductor. I just did a search and found they have 1,100 items that match 3.3 uH inductor. I need to narrow the search down a bit. See here: http://www.digikey.com/product-searc...=0&pageSize=25

If I need help determining how to specify a replacement part, I'll make a new post here on BadCaps. I'll include pictures of the failed component, similar identical components on the board, and a copy of the schematic that shows the circuit containing the failed component.

I'm not going to attempt to repair the inductor, unless, Ken determines that a new TCon board will fix his problem, and then I'm still not sure I want to sink any money into this TV. I don't need it, it belongs to my daughter. If she wants it repaired, I think I'll ask her for $100 up front. That would cover the $40 I sank into the un-needed inverter board, and a TCon board. I wouldn't put any of my own money into an LCD TV this age, with an unknown history. She bought it used several years ago for $400 when it was at least four years old. Not a purchase I would have made.

The last TV I purchased was a 40" Dynex LCD for $350 from BestBuy and I don't waste my money on the extended warranty. I'm sad that BestBuy has recently dropped their "value line" offerings. I guess there was no profit in them. Especially with a customer like me who refused to pay them $75 for a surge protector, and $50 for a gold plated HDMI cable. I don't own a surge protector and my HDMI cable cost $4 delivered from eBay.

[tw2005]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Ok I had a look at the Shopjimmy photo of this mainboard. I'm sticking with 000 are O ohm resistors however the space of the blown part does not look like the 000 resistor so you're most likely correct and it is an inductor. Could be marked 3R3M?

example: http://au.mouser.com/ProductDetail/B...brAiv2gToXg%3d

Do you still have the part from that location?

http://assets.shopjimmy.com/media/ca...j/sjn4ve_1.jpg

[tw2005]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

I think this may actually be it. Panasonic ELJFB3R3M (1AV4L2FB3R3MG)

[k2skaterii]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Hey Ken (k2skaterii),

Did you see my post above with detailed pictures showing the location of component L6172?

Please do me a favor and take a look at component L6172 (my blown component) on your replacement board and confirm that it is present and not fried like the one on my board. (Report your findings in this thread.) I've said I think I fried the component on my board when the test probe slipped, but who knows, maybe I didn't cause the failure. Maybe the component was fried all along. It is very easy not to notice that it's fried. It is a very small part. Maybe this L6172 is the achilles heal on this board. I spent a very long time inspecting the board looking at it under a magnifying glass trying to find any flaw. I think it took me at least half an hour to find that blown component.

The part labeled L6172 is not missing on either of the boards I have, the one I bought and the original board.

If I can find a T-Con board that is decently priced I will get one and see if it fixes the set... Maybe it will maybe it wont.... Either way I'll post it here. but I wouldnt expect any answer any time soon. I really wish I could test the T-CON before I purchase a new one, but so far no one has thrown any ideas my way to test it definitively.

[nd1377]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Thank you for this thread. Can you guys please update me on your TVs. I have the same TV with the same problem. Did you guys get them fixed and if so, how did you do it? Thank you very much

[BigJim42]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

I never got my TV working. Gave up.

[k2skaterii]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

Thank you for this thread. Can you guys please update me on your TVs. I have the same TV with the same problem. Did you guys get them fixed and if so, how did you do it? Thank you very much

I gave up on it as well. Replaced the Power board, the control board, the inverter board, the T-Con board... no change. Ended up eating a little more than $100 in parts.

Lets call it a lesson learned.

[Somnonaut]

Re: Sanyo DP42647, No Sound, No Picture, Can Switch ON/OFF by Keypad, Remote not avai

May I ask what you did with all the boards?