HAVE NO VOLTAGES ON SECONDARY OF SWITCH MODE POWER SUPPLY.
WHEN SET IS PLUGGED IN NO VOLTAGE ON COLLECTOR OF HORZ. OUTPUT TRANSISTOR.
173 VOLTS ON D OF Q101 REGULATOR.
DOES NOT MAKE A CHIRPING SOUND WHEN PLUGGED IN.
APPRECIATE ANY HELP.
1225 BIRMINGHAM ROAD
SULLIGENT, ALABAMA 35586
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This is fairly straight forward---if it got the fuse, input filter (big cap!) and the fuseable 7 watt-----
Understand (I do not know how savy you are) the power supply uses two grounds----on the primary side of the transformer (in power supply) it is from earth ground and on the secondary side from hot ground--when checking voltages= these are the key! you have to be on the correct ground to get correct readings.
Follow the money---the primary raw should be on that cap---follow it to see when it stops downstream.
220 can pop a lot of things---the set should also have a regulator IC in the power supply (could also be a big transistor) and if a chip--raw from that cap goes into it---and regulated comes out another pin---see if you have the raw and then see if at horizontal output collector and from there to flyback( with set off what is resistance reading from the collector of the output transistor to earth ground?
what kind of experience do you have with troubleshooting?
The power regulator board in your Hitachi is not switching. It is an SMPS [Switched Mode Power Supply]. Normally for plasma TVs the power supply repair will be almost impossibele due to lack of component availability. If the fuse is OK, definitley the switching process has failed it it. There is an IC which oscillates at high frequency, whic its oscillation signals are given to MOSFET transistors to chop the incoming AC, converted DC voltage. These switched voltage is passed through SMPS transofrmers which it turn generates secondary voltages that goes to different circuit boards of your TV. The power board is the most important section in a Plasma TV. it must be perfect in every respect in terms of secondary voltages. If any one of this voltage goes over than specified, the main boar will get damaged. So it is adviced to replace it as card basis, rather than making "sugery" to it. The power supply board can be had from Authorised Hitachi Service centers. You just give the the exact model number of your Hitachi TV. They will give you the orginal power supply board. Never play experiments with Plasma TV. OK.
It is very give you advice as you are aware of it. So do one thing. As far as the device is not turns on its power, the fault should be somewhere around the power supply system. Begin from AC mains chord itself. Check it for any break. If it is Ok, check whether supply is comming inside to your TV. Normally TVs have DPST type [Double Pole Single Throw] switches used for power switching. If any one of its poles not get correct contact inside, either phase or neutral will be cut. The click sound is not considered for its correct function. Check it also. It can be ckecked by measuring the voltage comes at rectifier points of your TVs power supply regulator section. If there is voltage, check the DC voltage across main filter capacitor. It must be some more than of your supply votage. I don't know the exact voltage you have as mains supply. Here in Idia, we have 220VAC 50Hz. At this supply voltage, DC voltage said above will measure more than 340VDC. Get a comparison with this when you check the voltage at the point mentioned above.
If it is also ok, there may be some fault in the oscillator section of the SMPS [Switched Mode Power Supply] section. There may be transistors or an Ic may be used to make oscillation to drive the switching transistor, which in turn drives the swiching transformer to get proper secondary low DC voltages needed to the circuit board. Check all the transitors. Of optocoupler is used check it also. Check its DC side control drive transistors.
Check all the zener diodes "off circut". ie take it out desoderd and check it with multimeter [preferably analogue type], set to 100K range. There should not be any leak at all. It is best to replace them.
Check all the resistors for its value marked, and all the transistors either for short or open.
Check the voltage input to horizontal output transformer [LOT]. Check the voltage at the collector point of the line drive transistor. If the line drive transformer primary gets open this type of fault mau occur. Also check the frequency ant the collector point of line drive transistor and the base point of line output transistor. It should be aroung 15625 Hz.
Check and replace the horizontal output transistor if needy. Replacing it is better. The horizontal output is not working or a short in secondary power supply of SMPS or lot secondary, is your problem
you need to check the voltage output of your power supply section.This power supply supply is a switching type power supply.there is a chopper transformer in there.its supply is a dc voltage unlike any other transformer which is AC supplied on the primary..First step. 1.Using a multitester measure the primary supply it is a DC voltage around 220v - 110 VDC 2.Measure the secondary output.The out put is AC voltage the supply for the B+ going to plyback is 115vdc the second output is 12v run through a regulator and the regulator lower the voltage to 5vdc.this 5vdc supplies the system IC and the jungle IC.this ic process the switching of the plyback transformer and the plyback transformers output supplies the voltage of the whole system including your relay in the degaussing section....once the plyback is activated the tv will now turn on...
there is a short circuit protection and overoad protection to smps so o/p capacitor may short or secondary diode may short .so check voltage at primary when switched off after 33seconds whether switching process is going or not for that check dc volt at i/p capacitor then check volt at collector of transistor if metr shows 1digit then switching is going if not then meter shows full dc volt check component near about that
the rca itc222 chasis has no front led diagnositc codes. Does the led flash imedatly when you plug it up. or does it start when you push the power button. if it does when you first plug it in then you have a problems with what is know as standy voltages. voltages that are always there when you [lug the set in. the processor does not see correct voltages. now if this flashes occur when you oush power button then there is problems with the secondary voltages also known as run supplys. does the set try to turn on do you hear static.. if not then you might have high voltage flyback or horizontal output problems.
You have a short in the power supply. Look at the regulator and or rectifier diodes. These are all on th primary side of the SMPS (switched mode power supply) the secondary side if shorted shouldn't cause a blown fuse at all.
This set normally has problems in the horizontal and high voltage circuit.
The horizontal output will short out and I often change the high voltage transformer.
The high voltage splitter is another one of the usual suspects.
Since it's ticking at plug in, then, I would look at the secondary of the high voltage transformer or the regulator circuit.
Checking the the horizontal output first for a short and if ok, checking the B+ voltage on the collector would be my next step. That should give a good thought as which direction to go.
Hope this helps.