I've been working on my Mitsubishi 65903. Plugged everything in this afternoon, powers up, no picture, and the main board chirps, not clicks, like a little bird about once a second.
Every heard anything like this?
Derek
I've been working on my Mitsubishi 65903. Plugged everything in this afternoon, powers up, no picture, and the main board chirps, not clicks, like a little bird about once a second.
Every heard anything like this?
Derek
Yea lots of times. You have a short in the main sweep board or in the power supply. Do you understand how a TV circuit works? Or can you read a schematic diagram? There is no quick fix, as you will need to start disconnecting different circuits as per the service manual schematic diagram and follow and trace the short out that way. If you have no circuit troubleshooting experience, I highly advice you to call in a pro to assist you in this repair. Good Luck.
I think I can do it, I do have all the service manual information. Wish me luck.
Derek
Larry,
I would imagine my short is near the STK, as that is what I've been working one, but I think I'll start at the chirping transformer and work backwards, just for the fun of it.
Derek
Thought I'd give you an update. Since the Main board was chirping, and I suspected the propblem on the Power board, I decided to check all the pins running between the 2 boards. Any common pins I looked at the schematic and sure enough, they were suposed to be connected.
I'm not sure what to do right now. I guess I'll pull the Power board and make sure there are no soldering mistakes.
Derek
Som you found some connectors or connections that were not connected. MMM Now you will need to see what these connections are part of and go from there. Triple check the solder connection on the convergence IC's and make sure they are not shorted anywhere.
Today's update:
I did end up finding 2 pins on the STK that shouldn't be touching. Fixed that and plugged in and noticed 2 of the big resistors burn. Even so, there was an image on the screen, a very bad one but still an image. I'll trace those 2 resistors back and see if I can find something. Wish me luck.
Derek
What two pins on the IC were shorted and what are the numbers of those two resistors marked on the board?, What is the STK Number?
Larry,
I didn't record which 2 pins were shorted. The 2 resistors that turned white hot and smoked ar R8D27 and R8D29. They are not turning white and smoking right now when I plug the set in. I'll take a picture of the screen later to give you a better idea of what my problem is. The STKs on my board are STK392-040.
Thanks for your help Larry.
Derek
Here is my poor little TV at this point. After changing many fuses and STKs it looks exactly the same:
Change the IC and make sure you have plus and minus 24 volts on the IC's.
Yes the STK IC and you will need to check to see if the plus and the minus voltages are on the IC as well. You really are going to need a service manual at this point i'm afraid. You can get one from here for 17 bucks. http://www.servicemanuals.net/results.aspx?type=SM&brand=0&model=WS65903
I have a service manual, it's really great. The one from servicemanuals.net is not complete, unless they changed it since last month.
I'll check the voltage. I'm worried to replace the STK's because that's exactly what I just finished doing.
Derek
Yes but you said you shorted out the pins. That could make the IC go bad again. You have to be careful with this solid state parts. They are very unforgiving. If you do not have much experience soldering, Pay someone to do that for you.
Larry,
On another board, someone told me to bypass the convergence. Would you know how I could do that?
Derek
Bypass the convergence? LOL, why would you want to do that?I do not know who you are talking to but I certainly would not. Not if you want a good picture.You can isconnect the power to the convergence circuit so you can see if the set comes on.
Right, I think it was just to take it out of the equation for testing purposes.
I have the picture shown in the above post. I wanted to try something to see what it did, so the 4 big red wires on the right, 3 of them go off to the tubes, I unplugged the one that went to the main board. Turned on the TV and had no picture. So, I plugged that red wire back into the main board and no picture. I don't get that, it worked just before that, when the red wire was conected. Any clues?
Derek
Oh, and the people who suggested bypassing the convergence were CraigR, ServiceTech and Chuck Williams on The SPot (hometheaterspot.com)
What was the method they told you to bypass? maybe your explaining something the wrong way? You need a complete service manual. If you are working with a partial, as you say, you are still working in the dark. Send what you have to [email protected], let me see what you are talking about. Explain how they want you to jump out the convergence circuit, as I have never heard of doing this before.