I've located a shorted transistor in the power supply on this set. I purchased the Sony power supply kit (3 trans and 1 resistor). I know where the transistors go but I have no idea what to do with the 1/2 ohm resistor. Please advise
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Re: Sony TV KV-32v15 Dead Power Supply
You should of recived a 0.01ohm resistor it is wite and sayes sony on it.
its a flame proof resistor that needs to be the very same
look for it on the pcb test it its probly open right.
ask them to send you the right part.
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Try this: unplug the set and wait about 10 or 20 minutes. This is to make sure that the main power supply filter caps completely discharge. Look on the power supply board, close to where the AC cord attaches to the board. Look for a white resistor labeled "0.1 OHM" (the symbol for OHM, like an upside-down U) and measure it with your ohm meter. If it is open then your switching transistors in the main power supply are most certainly shorted. Older sets had 2 separate transistors on little heat sinks labeled "C4834", then they switched to 2 transistors in one package labeled "MX0841" or "MX0842", and then some sets went to two separate MOSFET transistors. Measure those parts and post your results and we will guide you from there.
Check your TVs power supply regulator section for any loose sodering points in it. The regulated voltage comes from it is more thatn normal. Check out all the soldering terminals. It is best to resolder all the suspected solder terminals by applying a little more solder, without making any solder bridge short in between adjecent solder points. The fault symptom as reported by sony is:-Two blinks - B+ over current protection (OCP), unit goes to the standby mode then displays the 2 blink fault. Could be a short in the power supply of any of the circuits. Check for any short circuit in the secondary section of the SMPS power supply section. Check the horizontal output transistor for collector to emitter short. OK.
Check the input fuse first. If it is blown, there will be some short inside the power regulator circuit. Usually Sony sets uses STR regulated power supply. You can see this STR, and Ic, screwed onto a heatsink. Replace it with a same type and number. Before replacing the STR, check the diodes used in that section for damage, mainlu zener diodes. They might get shorted along the blowing of the STR. Check that section throughly before resoldering the new STR.
If any further assistance you needs, get me through Fixya. Ok.
check for an open resistor on the power supply, it is actually a fusible resistor, (white) if open, then check the converter, some sets have two separate and some have it as one. it will be on a heat sink on the power supply. if shorted then check for a shorted horizontal output transistor and repair cold solder joints on the horizintal drive transformer which is the real cause of this problem
Usually, in those Sony sets, a crack developes on a small transformer in the horizontal drive circuit, which causes the horizontal output transistor to short. This immediately shorts out the switching transistors in the power supply and blows the Sony 0.1 ohm resistor fuse. A shorted flyback (high voltage) transformer will also have the same result. The power supply does NOT need to be replaced. The parts should be replaced, the flyback checked and the board resoldered by a qualified tech familiar with Sony sets.
The most common problem with TV was the failure of the Horizontal Output Transistor, this will also damage 2 transistors in the power supply and a resistor in the power supply also. (From memory): Horizontal Output location # Q501, 2 power supply transistors Locations Q601, Q602, and resistor Location R607. Also solder the Horizontal drive transformer, you can find it by following the circuit board from the base of the Horizontal output. Some models used an IC instead of the 2 transistors in the powersupply, it will have six legs and check like 2 transistors. Good Luck.