Question about Sanyo DP50747 50 in. Plasma TV
This seems to be a common problem on this model. My set started acting up a few months back and has gotten progressively worse. When I attempt to power up the TV the green light comes on, the screen starts to come on, then poof the screen goes dark. Several seconds later the green light goes off. After numerous attempts I'm able to get the set to work. This morning it took me about 15 attempts to get the TV to come on. Once the set is up and running it works normally for the most part but it occasionally shuts off by itself. As long as the set's still warm, it will turn back on normally, but when it's been off and is cold it takes repeated tries to get it back on. I use to be a TV tech years ago and my first suspicion was a power supply issue but I'm not so sure after reading some of the posts out there. Whatever the cause, this set is obviously defective. My set is under 2 years old and judging from what I see online Sanyo should recall this model or offer free repairs. If anyone knows what board or component is causing the problem I'd sure love to know.
You will need to remove the back cover to troubleshoot the plasma you will also need a digital multimeter. With out doing an troubleshooting it is hard to say so i would recommend following a troubleshooting guide, in my experience no video is ussually a failed Z sustain.
First look for missing voltages at power on each connector should be labled with the proper voltage. If you have one start with the missing voltage and troubleshoot back, it is hard to say what the ultimate failed components would be but you should be able to track it to one board.
Rule 1 is troubleshooting is "start with your sense"
4. Touch (not recommend)
these are the best giveway, if it looks damaged it is if it smells burn it is, if it sounds wrong it is
1. Look - examine each component on the board look for something burnt, swollen or distorted, and look at the fuses.
2. Smell - Smell around the set see if you can smell a burning smell on any of the boards .
3. Listen- Listen for a buzz or an arc out of one of the board, it may be normal but unlikely if you have a defect.
4. Touch- Important because if the parts are getting hot then they are running, but if they stay cold they are not.
As for touch not the best idea on a power supply there is a high risk of shock, as some of the heat sink may not share ground and possible have a potential to earth ground between 5-500 volts.
You will need a DMM to check the diodes and the transistor non should read a short, if any do you will need to remove it and check it out of circuit if the component is not shorted but the short is still in circuit use the schematic to follow the leads to where else the short could be coming from and repeat.
I would have to say unless you are fimilar with repairing with a schematic it can be complex. Your best bet is to do what best buy techs do.... Replace The Board. It is the fastest sure fire way to fix it.
Next remove the connector connecting to Y sustain and the Z sustain to the power supply and attempt to power the set on if the set powers with the connectors disconnected you have more than likely identified the issue as a failed sustain board now to go further.
THIS IS NOT YOUR SET BUT A GOOD EXAMPLE.
Now reconnect the power connect to the y sustain and see if the set powers remember you will not get a picture but the lights on the front should stay light.
If the y main connected causes the set to act up remove the buffer boards and attempt again, if the y still causes the issue you have a failed y board. If disconnecting the buffer resolved the issue you have failed buffers and possible a failed panel, try replacing the buffers.
If the Y board connected the set still light normal disconnect the board and connect the z sustain and test the same as the y, if that causes the issue replace the z.
If you want to contact Sanyo :-
SANYO North America CorporationHeadquarters
2055 Sanyo Avenue
San Diego, CA 92154 U.S.A.
Phone: (800) 877-5032
If you want to purchase the Board yourself, below is the List of Manufacturers :-
Hope i helped you.
Thanks for using ' Fixya ' and have a nice day!!
Posted on Oct 01, 2009
If this model has a switching power supply then it could be a short anywhere overloading the supply. The H out transistor is easy to check for a shorted condition (unplugged, ohmmeter across C-E pins should NOT read 0 or low ohms), also the secondary rectifiers (I've seen them short on occasion).
Otherwise, in my experience I more often see shorted yokes than FBT's in Sanyos. Try unplugging the yoke plug and powering it up just briefly. If the noise is gone, then it's your yoke. (Some yokes are bonded to the tube and are impossible to remove. CRT replacement is not practical)
Posted on Oct 01, 2009
Personally, I don't have an experience with the model number that you indicated but I have already seen this issue before on others TVs.
What happen with your TV is; when the TV is turned on, the power supply detects there is a short circuit or something that is using a lot of current. Therefore the circuit protection turns off the TV. Trying several times until bypassing the circuit protection will keep the TV on, but that doesn't fix the problem; the -suspected- short circuit still there.
So, I agree with you, this appears to be an power supply issue, BUT, it may not. I can't actually diagnose at the tv over the internet. (I guess nobody can) So, replacing the power supply is not guarantee that the problem is fixed. The source of the failure could be anywhere in any board in the TV.
If you feel confident with your experience fixing this TV, I recommend you to start looking on the power supply, the problem maybe a bad capacitor , transformer or power transistor on the power supply board. You can find and purchase a Service Manual over the internet; It will help you diagnose the source of the problem and fix it by soldering in the new part. The Service Manual will give you circuit diagrams, test points, and part# lists. Usually, cost under $20. And most cases the new part cost less than $15. In case a complete PCB needs to be replace, it will cost about $150.00 - $200.00
Before getting the TV fixed by a service company, I highly recommend you to request a quote first, the repair costs may be high and will be better to get a new one.
Hope this helps, good luck!
Posted on Oct 01, 2009
In the DP50747 Owners Manual, you can find this tips about your problem, review the page 17 for troubleshooting.
Also you can visit www.sanyoctv.com or call for free at 1-800-877-5032
I hope help you with this.
Posted on Oct 01, 2009
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Posted on Jan 02, 2017
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