PWB-0653-02 Power Supply Unit Board not starting

Diodes dont get cut in half. There is no schematic available for that unit. Your best bet is to get the board that it is on and replace the whole board if you can. Diodes dont oscillate, they rectify. The only way around this issue is to get a meter and measure the voltage and then measure the impedance and calculate the current and look for a diode with those specs.

the problem isnt in the power supply unit, put back the original power supply instead, check the heat section of the board where you can see the flyback section, verify the high voltage input by using the voltmeter , if high voltage is missing check all the capacitors and diodes near the highvoltage section, if blown replace it with the same value.

Hi Scott,

Here are some basic steps that will help you fixing the problem.

I'm assuming that your unit is dead set without an standby LED light and your outlet is live.1.Power cord - check the cord it might be opened (no continuity).This is due to frequent bending,pulling. 2. Power switch - check for dry joints, open contact. 3.Check the internal fuse- sometimes the fuse fail because of the power surge, replacing with new one will cure the problem, If this is the case I would advice you to use surge protector/AVR (Automatic Voltage Regulator). However if the fuse blew again this is an indication that you have a shorted parts in the power supply, you may visit the linkhttp://www.fixya.com/support/r8053361-fuse_keeps_blowing for more info. If no reaction and still the unit didn't power up then you have an open parts on the power supply.

4.If you see that the fuse is intact , don't attempt to touch anything because there some fatalcomponents stored electricity enough to hurt you with a simple mistake only. I would advice you to look for a professional to troubleshoot the power supply. If you want to repair it yourself make sure that you have necessary tools and test instrument. First check bad solder joints(re-solder all cold solder), leaky electrolytic capacitor(sometimes it has bulged at the top but not all, you better have a capacitor checker), open/shorted regulator transistor/IC(mounted in heat sink), open fusible resistor (caused by shorted regulator Transistor/IC), shorted zener diode.

You may also replace the power supply board, check it online like ebay.com and shojimmy.com.

Also, check if your unit is under warranty before opening the back panel, it will void the warranty. Avail it because the manufacturer of your unit will fix it for free or a little charge only.

Hope I helped you.

Have a nice day!

Thanks for using fixya.

Troubleshooting of Inverter Circuit (U) and Magnetron
This oven is programmed with a self diagnostics failure code system which will help for troubleshooting, H97, H98 and H99 are the provided failure magnetron and inverter circuit problem areas. This section explains failure codes of H97, H98 and H99. H97, H98 and H99 appears in display window a short time after start key is pressed and there is no microwave oscillation.



NOTE: DO NOT try to REPAIR this Inverter Power Supply (U) and also DO NOT RE-ADJUST PRESET VOLUME on the board. It is very dangerous to repair or adjust without sufficient test equipment because this circuit handles very high voltage and very large current. Off alignment or inverter board operation is dangerous. Operating a misaligned inverter circuit is dangerous due to the very high voltage and current that is produced by this board. Defective boards must be replaced with a new one.
- Check magnetron filament for open or short to casing before proceeding to determine a good magnetron.

Alternative way to troubleshoot oven with AC Ampere meter used. H97, H98 and H99 appears in display window a short time alter start key is pressed and no microwave oscillation with AC Ampere meter used for troubleshooting.



NOTE: DO NOT try to REPAIR this Inverter Power Supply (U) and also DO NOT RE-ADJUST PRESET VOLUME on the board. It is very dangerous to repair or adjust without sufficient test equipment because this circuit handles very high voltage and very large current. Off alignment or inverter board operation is dangerous. Operating a misaligned inverter circuit is dangerous due to the very high voltage and current that is produced by this board. Defective boards must be replaced with a new one.
- Check magnetron filament for open or short to casing before proceeding to determine a good magnetron.

Hope this helps.

Good day!

This are the steps to find and fix that problem.

1. Open the cover of your TV.
2. Disconnect the input supply of system board or main board that comes from the power supply unit.
3. Power ON the TV to check the voltage reading of disconnected connector to the input of system board by using voltmeter.
4. Check the 5vdc and 12vdc by using voltmeter.If you got voltage reading of 5vdc and 12vdc,try to connect the input connector of the system board and check the voltage again.If no voltage when you connect it.There's a shorted parts on your system board.Replace the whole system board because its very difficult and expensive to repair it.
5. When the input voltage of system board doesn't have 5vdc and 12vdc even disconnected on the board.The problem is on power supply.

Check the following:

• Fuse-Check the fuse if busted.
• Transistor and diode-Check the transistor and diode if shorted.
• Resistor-Check the resistor if open/change value.
• Capacitor-Check the capacitor if leak/bulge on top.

If you found the defective parts that mention above.Replace it with the same type and ratings.
NOTE:If the following parts are OK and the problem is still there.The power supply have major problem and its not for D.I.Y..

Thank you and good luck

Only if the power supply has been restored back with the replacement of the capacitor and fuse can we proceed forward. If not you will need to check the SMPS unit to replace damaged components to restore the supply.
If supply seems correct, then check the +5 to the processor unit. In event of high voltage it is possible that the mother board is affected.

Ahem, forgive me for being upfront...I am trying to help you, not to offend you, so bear that in mind.

Your language is quite non-technical and would be easy to follow; respectively it would be hard for you to follow instructions before first getting some education about diodes, capacitors, rectifiers etc.

And given the apparent lack of experience servicing electronics on your end I would suggest that possibly the easiest way to get your TV up and running is to buy a new power board.

I was thinking of offering you to send me yours for service, but considering you can get a working one on eBay for $70 delivered I don't think it's worth the attempt.

Once you get a working board you can start comparing the two with an ohm-metter and see if you can find which component is faulty.

I am not saying that;'s the best way to do it, of course, but if you want to spend time learning things it's a good way to start.

The E7-02 means the beam detect sensor never received a beam from the laser. As the previous poster stated you'll need a new laser unit. Meaning that you need to change the whole laser unit but not the polygon motor.

E7 02 Content Laser trouble
Detail BD signal from LSU is kept OFF, or ON.
Cause The connector of LSU or the harness in LSU
is disconnected or broken.
The polygon motor does not rotate normally.
The laser home position sensor in LSU is
shifted.
The proper voltage is not supplied to the
power line for laser.
Laser emitting diode trouble
PCU PWB trouble
Controller PWB trouble
Check and
remedy
Check for disconnection of the LSU
connector.
Use DIAG (SIM 61-1) to check LSU
operation.
Check that the polygon motor rotates
normally or not.
Check light emission of laser emitting diode.
Replace the LSU unit.
Replace the PCU PWB.

Replace the Controller PWB.

If power supply is good and voltage measures out ok. Also check any relays or capacitors.If LCD, check caps, if projection, check bulb and high-voltage transformer and flyback with a voltmeter.
Capacitors are the most common reason for failure in today's electronics.

just take your tv to a near w/shop, and ask a tech, to check components, on the power supply.
components like transistors, diodes, ic if any on thepower supply,all eletrolitic capacitors values, and change all changed value capacitors. because if capacitors change values they change oscillation hence increasing current output.
if you do that your set will come back to life again.