Question about Mitsubishi WS-55807 TV
Hey, you look like a guy with a lot of answers. I have the same problem this guy posted where the screen goes blank after a few minutes--you wrote you needed more info, and i didn't see him reply...if you can help me i'll give all the info you need.
so: the tv will have a picture for a minute or so, longer, then it won't. hitting the side brought the picture back, but now it's not doing it so much. unplugging it and moving it to unplug it, and plugging it back in, the image comes back, but then it disappears again. sometimes it will stay for a while and all's fine; sometimes it needs to be tapped every five minutes. now, it looks like there's an image struggling to get back on the screen, and when i press the "format" button on the remote, it will go from dark black to a more active black, sometimes bowing down at the top with some white lines. usually, if the screen looks like it's actively blank, the taps work to get the picture back.
so that's that, please let me know if you can help.
If your not a tech, its highly advisable to not even open the set because of the high voltage and x-ray radiation issues. Now if your a technician ,you gonna need to get a service manual, Look up the convergence circuit, Find the two or three convergence driver ics, find the b+ feed resistors to those ic, and order the exact replacement parts. if you dont replace all at once, and with exact replacements, you will be in the same boat a few months down the road. This is not a repair a handi-person should consider doing as even if you get the ics replaced, your gonna need to do some minor or could be major convergence alighnment and your gonna need a cross hatch generator to do this. This repair should cost ya about 300 to 400 bucks? Sorry man Good Luck
Posted on Jun 14, 2006
SOURCE: Mitsu 55'' screen
The convergence ICs probably have a cracked solder joint on the foil side of the circuit board. Re-flowing the the solder would help. I will always replace the convergence ICs when doing this job. The labor remains the same and you will have to pay a few extra bucks for the parts. To fix this yourself, you will need to be able to identify the two convergence ICs (STK392-570), have a basic knowledge of electronics and be able to use a soldering iron.
Posted on Feb 18, 2007
I have a WS-55807 that will not power up. When the power button is pressed I hear a click from the back of the set, the timer light comes on and 3 seconds later I hear a click from the back of the set, and the timer light goes off. I started checking power to the unit with a voltmeter. For those intersted I have attached scematics: I verified that the PCB main fuse is good and there is 120V at point PT.
From what I can tell is happening, the power button is pressed and the P-ON transistor is given a signal to conduct which causes K9A50 to close. K9A50 opens after about 3 seconds.
I am looking for other troubleshootinng steps. I have checked fuses F9A01 and F9A06, both are good. What are some other things to check for? Where does the P-ON signal come from?
In the switched supplies regulator circuitry I found fuses F9A04 and F9A05 blown (denoted by red lines thru components). I jumpered around F9A04 and F9A05 with good 5A fuses and the TV powered on. However when the set was plugged into an outlet there was a huge power draw (sparks from the outlet).
After jumpering around the blown fuses, the TV stayed powered on for about 30 sec and then powered down. I pressed the power button a few more times and the same result. The TV stayed on for only 30 sec.
I pulled the middle PCB whichs holds these circuits and I found the
D9A60 diode open and IC8C02, one of the convergence IC's fried. I don't know if these were like this before or after jumpering.
I replaced all bad components and I am back to square one. The K9A50 relay stays closed for 3 sec and the set does not power on any further.
Comment by TV_ITGuy, posted on Dec 19, 2007 Thanks for the advice ctf1800. I have read several posts that speak of the DM unit. I have looked in the back of my set and the DM unit is not in the location shown in the pictures.
As I hope you can see in this picture, there is no DM unit to the far left, just open space. Also the service manual for the V17 chasiss does not speak of a DM module.
I checked the reisitors on the output of IC8C02 which are a couple of 3.9 ohm resistors in parallel. When I test them I get approximately 1.9 ohms, which is what it should be with them being in parallel.
Please let me know if I am off base on any of this. Thanks Comment by TV_ITGuy, posted on Dec 19, 2007 Also, I have replaced both of the Convergence IC's when I replaced the fuses and diode. Post Solution Work Queue --> Have the same problem? --> Have the same problem? Click Here
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Rating: 84%, 2716 votes
first off you should replace both convergance IC and check the resisters coming off the output if any of the resisters are bad it will trash the ic on trying to power up.
i would also replace the caps in the DM section
Comment by ctf1800, posted on Dec 20, 2007 there are six fusible return resistors ranging from 1.5, 1.8, 2.2, 2.7, 3.3, 3.9 Ohms. I would lift one side of the resister out.
check for any caps that look puffy and check the horz. out put transistor.
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Posted on May 29, 2008
Good Day; This model is equipped with a self-diagnosis feature to help with diagnosis of shutdown problems. To activate this turn the unit on let it shutdown then press the input/device and menu buttons on the front panel simultaneously and hold them in for 5 seconds after 5 seconds the power LED on the front panel will blink a two digit sequence. This will be one set of blinks a short pause then another set of blinks, this will repeat 5 times. 1 - 2 = no error detected 2 - 1 = X-ray protect (high voltage or beam current) 2 - 2 = Short protect (short protect monitors low voltage supplies) 2 - 3 = Deflection protect (this could be loss of vertical or horizontal deflection) 2 - 4 = Vertical protect (usually loss of vertical from the source) 1. SELF- DIAGNOSIS INDICATE X-RAY. CHECK FOR A SHORTED IC5A03 PART # 270P704010 AND AN OPEN R5A73 82K ¼ WATT OFF PIN 2 OF IC5A02 ON THE MAIN PCB. 2. SELF DIAGNOSIS ERROR INDICATES SHORT PROTECT. CHECK FOR OPEN FUSES F9A04 AND F9A05 PART # 283P043090 ON THE +24 AND -24 VOLT LINES. IF THE FUSES ARE OPEN THE CONVERGENCE OUTPUT CIRCUIT WOULD BE SUSPECT. 3. SELF-DIAGNOSIS INDICATES SHORT PROTECT. CHECK FOR A SHORTED IC4B01 PART # 270P261020 (VERTICAL OUTPUT) LOADING 24-VOLT SUPPLY LINE. LOCATED ON THE MAIN PCB. Good Luck, big IRISH.
Posted on Sep 25, 2008
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