My samsung projection TV died... so i was fortunate to pick yo this Mits ws65905 in town knowing it wasnt powering on. After reading for two days i have checked the conversiance chips and found the solder cracked on them. Have resoldered that .. but the problem persists. I assume it is the protection circuit turning it off. TV will turn on with remote and start clicking in a minute or two. The CRT's flements are not energized. I have downloaded a service manual for it and wonder if anyone would direct me to where to start or if anyone has ran in to this problem and fixed it correctly. Thanks Maugli
Replaced Convergence IC's and now it powers up with two clicks of relays instead of one. The Turn on clicking is about 4 seconds apart. But the Crts still no energised. The LED flashes 12 so it cant see the problem. Need guidance.. can use tools. Tektronics 60mgz Scope on the bench. HELP
Well Lots Of Help in her for newbies.. but here it goes. My testing showed that i do not have a stable -34v and +34 volts on D9A21 and on D9A24. Further testing showed taht the Q501 had a dead short from amu pin. Taking it out of the circuit confirmed it. It is a 2SC5418 NPN 1700 watt transistor. I had a 2SC5148 NPN 1500 at hand so i put it in thinking at least i would get TV to FIRE. But it did nto happen. The voltages still fluctuate. The new transistor did nto blow i took it out and it is still intact. Testing with meeter set to continuity i have noticed a short between B and E pegs in any dirrection. Looking closely at the schamatics i have noticed that current limiting resistor R516 is the cause of it. R516 value is .56 OHMs . That woudl be interperted as a dirrect short by the transitor Q501. My Question ... is ... WHAT AM I MISSING. I did not thing that smaller wattage transistor will make such a diff. Guys i really need your input... i have only few hairs left :-) Maugli
Well here is an update. The original Panasonic HDT came today. One thing i have learned there could not be any substitute in this circuit because the Q501 is being fed 94 V from Q503. If Q 503 has not failed then the transistor thats it is feeding will hae to match the cisrcuit parameters in order to function properly. There fore my substitute transistor did not work. After the instal of the origonal transistor... The voltages on the secondary side of T9A00 have stabilized. I had stable -34V and bit did nto have +34. Further testing showed that F9A21 F9A22 F9A23 5A fuses were blown. I will replace them tomorrow i hope. But i still wonder what the hell could have created that type of damage. COnvergence IC's? The HDT? Or it was jusy hit by Lighting. :-)I hope it will fire after the fuses are replaced.
Convergence done .. dod nto replace the meltsd lens. Cante realy see any diff. Took me a day to undrstannd how to congerge properly. but it is done and WORKING!!!!!!!!!!!!! Thank you guys for all the reading i had to do to understand this. Even i got no answer to my posts i am thankfull for all the posts and all the help that was given on this site.