How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Noetvs Your Own Question
Noetvs, Technician
Category: TV
Satisfied Customers: 158
Experience:  30 years on TV repair bussines
Type Your TV Question Here...
Noetvs is online now
A new question is answered every 9 seconds

Emerson LD200EM8 LCD TV/DVD combo, wont turn on.

Customer Question

Emerson LD200EM8 LCD/DVD combo, repairing power supply section. Need value of very small Zener Diode D624 on hot side of switching transformer, it is shorted among some other faulty parts mentioned below. The only markings I can maybe read appear ? to be "3 8 B"..? ?. I think that is what the markings are, it is very very hard to read and it is burnt and discolored. Maybe 38Volt 1/4 watt??? I really am not sure of the number on the diode, can you help me.

I also found an open 4 Amp line fuse, a shorted Zener Diode D624 (voltage rating??) on primary side of SMPS mentioned earlier, a shorted Q601(2sk3563,power mosfet on SMPS primary) and a shorted D901 "fast" diode on secondary side. Is there anything else that commonly causes the dead set symptom on this model that I might have missed????

Thank You

Submitted: 8 years ago.
Category: TV
Expert:  Noetvs replied 8 years ago.

graphicHI, how are you?.
Look, I have this information for you; Go to this place and you will find your main power supply. ( 2 places)


provide model number tv and they will you right parts; ( 2 first places is for a power supply board) . Emerson parts work same with funai brand.

If you feel satisfy with my answer, please check accept button; have nice day!!

Customer: replied 8 years ago.

Dear Noetvs,

Thank you for your reply, I was not interested in replacing the entire boaard, so the ebay link is not what I want to do and the 2nd link only wants to sell an entire board and they say it is OUT OF STOCK so that is no help what so ever. The 3rd link does NOT work, the page comes up with an error message, I have tried it on two different computers and it does not go through. So, I am batting a Zero for Three.


I DO NOT need to order any parts, I HAVE ALL THE PARTS I need to fix this unit, I have already installed the fuse, the mosfet and the high speed diode, and I have a complete stock of Zener diodes so as my original question was worded, I just want to know the "voltage" of the shorted zener diode D624 so I can replace it. The only markings I can maybe make out on the damaged and hard to read part are " 3 8 B", but I am only guessing. So, if you can find a diagram or parts list for the board and tell me the voltage of the Zener or the industry standard part number or even a ECG/NTE number it will be most appreciated.... or can you direct me to information on the internet that will answer my question?

Please give me some kind of reply so I know that you are working with me on this, I am looking for your assistance on this.

Thank You

Expert:  Noetvs replied 8 years ago.
Ok, can we continuous tomorrow, please?. ( am in my house right now, but tomorrow in my shop I will check again my reports tv) am in north Carolina 1120 pm. Is fine?. I will help you . Thank you. Have nice night!!
Customer: replied 8 years ago.


Thank you for your reply, I hope that you will be able to find the information I am seeking. I am on the west coast so it is not quite 8:30pm here. I am always up very early in the morning so feel free to reply whenever you can on Thursday morning, I want to get this fixed as soon as I can.

THANK YOU again.

Expert:  Noetvs replied 8 years ago.


Hi, good morning !!. I am here in my shop, I have a tv emerson with me ( working) I did open and find your Diode number:


Part number MTZJT-7733B ------------ 33V/1W zener diode


If you feel satisfy with my answer, please check accept button. Hvae nice day!!!

Expert:  Noetvs replied 8 years ago.
If you feel satisfy with my answer, please check accept button. Thank you
Customer: replied 8 years ago.

Now I really am confused, I found someone who has a partial diagram for the unit

and it specifies a MTZJT-7739B, a 39 volt zener.

After looking at the burnt part even closer, it appears that the number is XXXXX fact 3 9 B .

Are you 100% certain about your information? Hmmmm, what should I do?

Expert:  Noetvs replied 8 years ago.
Customer: replied 8 years ago.
? ? ?
Expert:  Noetvs replied 8 years ago.

I have a same chassis with me........Why you said if is not right part number?.....Thank you


If you feel satisfy with my answer, please check accept button. Thank you

Noetvs and 3 other TV Specialists are ready to help you
Customer: replied 8 years ago.

Ok, as long as you are sure that it is in fact a 33 volt zener diode I wlll accept that. Pray that I don't get smoke when I plug it in!

Thank You for your assistance and answering my question.

Expert:  Noetvs replied 8 years ago.
Hold..Hold!!!...If you have any short in the front...DOn't tell me this statement. Are you sure you dont have any short circuit in the front?./......DOn't worry about ,money....if you feel diferent...don't worry..don't pay. Common problem on this tv is bad power supply....Big trouble!!!! ( some times diodes are defective but show good )
Customer: replied 8 years ago.

Dear Noetvs,

Well, here is some information for you. I now have a PDF of the Emerson/Fuani LD200EM8


On the parts list on page 71 you will see that D624 is in fact a

39 volt zener, MTZJT-7739B and NOT a 33 volt zener as your

reply stated.

Also on Page 45, it shows a schematic of the power supply, D624 is shown with it's cathode connected to the "source" of Q601 power MOSFET, and the anode is connected to ground.


Once I replaced the incorrect 33 volt zener with the proper 39 volt zener the unit now works.


I really wish that you would have been 100% certain of your information that you gave to me, it would have saved me a lot of time and some MONEY$$$. I hope that this information and the PDF manual helps you in the future. Hmmmm, I probably won't get a credit for the fee that I paid, maybe I should get paid?

Expert:  Noetvs replied 8 years ago.
Do you know we have a range parameter for some power supply parts Right?????. Like 1uf 160V you can use 2.2 , 3.3 uf to 160 Volts.......... Right?.. Please dont try to show me confuse electronics skills...WE HAVE PARAMETERS VOLTAGE where we can work and replace different size diodes, and still work same.........PARAMETERS OR RANGE VALUE PARTS !!!!!!!!!!!!!!..... Please can you explain to me about the difference in this diode.. 33V--39V ????????????.....(6Volts???????, are you think whit 6 VOLTS you will have a problems...........Now, did you see how is connected in the power supply?...............Don'T worry about your money......Let me try to email to justanswer and request your money back.........I did replace a dozen diodes like this.....Please!!!!!!!!!!!!!!!!. Thank you .