No power displayed on my DMR77LHS

dear its related to the fuser assy. check the thermostat for open replace it,check the thermister for open.replace it. Thane Main PBA. In general this type of model if problem repeated replace the Main PBA or update firmware with latest. Thanks.

see the next causes. God bless you
Diode The high voltage diode converts the A/C power output of the transformer to D/C, doubling the voltage to nearly 5,000 volts. This high voltage powers the magnetron which emits the energy that cooks the food. If the diode burns out, a lower A/C voltage reaches the magnetron, which is not sufficient to power the magnetron. When the diode fails it is often visibly burned out. If it appears to be good, it can be tested with a volt-Ohm meter capable of testing diodes. High voltage diodes frequently fail and are one of the most common points of failure in a microwave oven.

Door Switch If the microwave does not heat, one of the door switches might be defective. Microwave ovens normally have three door switches, if any of them fail the microwave does not turn on and does not heat. Check the switches for continuity with an Ohm meter.

Magnetron If the microwave oven doesn't heat the magnetron tube might have burned out. The magnetron uses high voltage, high current DC power to generate the microwave frequency that cooks the food. If the microwave oven is turned on when it is empty this can cause the magnetron to burn out. Once it is burned out it has to be replaced, it's not repairable.

High Voltage Capacitor If the microwave doesn't heat the high voltage capacitor might be defective. The high voltage capacitor works with the high voltage diode to convert the output of the transformer to DC voltage and to double the output voltage. If the capacitor is burned out the entire high voltage circuit stops working properly. The high voltage capacitor can be checked with a special VOM meter which has a capacitance testing capability. Be aware that the high voltage capacitor can retain a charge of more than 3,000 volts and can injure or kill a person if not handled properly. Only trained technicians should perform this type of testing.

High Voltage Transformer If the microwave does not heat, the high voltage transformer might be burned out. Microwave ovens produce a very high voltage in order to power the magnetron antenna, which emits the energy that cooks the food.

Thermal Fuse If the microwave doesn't heat the thermal fuse may have blown. It can be tested for continuity. Watch our fuse testing video for more information.

Thermoprotector If the microwave doesn't heat the thermoprotector may have tripped. This is a safety device to prevent the microwave from overheating. It can be tested for continuity to see if it's blown.

Main Control Board If the microwave doesn't heat the main control board may be defective. This is not common. When a microwave doesn't heat the problem is usually within the high voltage circuit; either the high voltage capacitor, diode, transformer or magnetron.

If it is E2 15 then it may be a switch error (Main Relay error) Check for stuck button switches or power button switch for sticking. May need to replace the main PBA. Verify the error and provide the model number to verify the error code specific to your model.

okay. Solution pertains to device errrors 22 thru 25.
step 1: Is the cable from the fuser firmly connected to the Low Voltage Power Supply at (CN3), between the mother PBA (Cn24) and the Main PBA (Cn12)?

step 2: Is cable from fuser firmly connected to the mother PBA (CN4) between mother PBA (CN25) and the Main PBA (CN13)
step 3: if connections seem good and problem error code persists, replace in this order:
1. Fuser (call 888)690-7283 to order.
2. Low Voltage Power Supply
3. Main PBA
4. Mother PBA.

First check is the main fuse of the unit. On countertopunits, you will need to take the shell off. The fuse will be close to where thecord comes through into the unit. OTR units, this main fuse is usually behindthe control panel or possibly behind the vent. Usually the fuse is obvious ifblown, otherwise test with an OHM meter, if open, replace fuse. Some brands will also have a thermal cut-off fuse in theincoming voltage line to the control board. This thermostat looking fuse isusually above the oven cavity somewhere under the outside shell. Sometimes youcan get to it through the vent of OTR models. Test with an OHM meter, replaceif open. Forturntable: First, make sure the turntable coupler under the glass dish is notbroken. Second, on the control board, find the turntable relay and test forvoltage. Some turntable motors are 24 volts DC, so make sure you're testing thecorrect voltage. If no voltage from the control board, then replace the controlboard. Otherwise head towards the turntable motor. On OTR models, you can get to the motor by un-screwing thebottom panel on the microwave. On countertop models, there will either be aknockout or screw on access panel. Check for voltage at the motor. If novoltage, check the wiring back towards the control. If voltage, then replacethe turntable motor. Hope this will help you. Good Luck.

Plasma sets have two separate power supplies; the main supply produces voltage for everything and may even produce a specific voltage for the high voltage required by the plasma display.
In your case, it is likely that the latter (HV) supply has failed.
This may be a separate board and if so, may be user replaceable since these are normally outsourced and just plugged into the set during assembly.
Removing the back of the housing, you are likely to see at least three boards. One of them (the main board) will have many components and most will be smaller in size. The main power supply will have much larger parts on it and the high voltage supply will likely be connected to it and have far fewer parts than the other boards.
It is possible but unlikely, that the main power supply is not providing voltage to the HV board for the display.
If replacement of the HV board doesn't restore the display, then it will be necessary to replace the main power supply too.

Hi, whenever a fuse of that magnitude, or any fuse really, Blows, you should never just replace it, as to have any device, blow a fuse, trip a breaker, requires a major fault, they do NOT blow spontaneously ever. So you have had a major short circuit inside your machine, at some stage, usually this is in, the main Controller Board, most likely the bridge rectifier has gone short circuit, or a capacitor, But it could be anything even the motor?anything like this then will blow the fuse. The reason the fuse blow is to prevent a fire and explosion or both, as if an unlimited amount of current could be drawn, it would be catastrophic, so a fuse blows to disconnect the power. The Cause of this MUST be discovered before one ever attempts to replace the fuse. Luckily, it seems in this case the fault has blown an open circuit on the main Board, and this has prevented any further trouble.
Really after such an event as this one should engage the services of a professional, as anyone untrained may mis something that later on my even prove fatal. Get this unit looked at by a professional service person, ask for a 'Quote" if concerned about costings, then you can make an informed decision as to what to do.

Your support site is below,
http://www.samsung.com/us/support/detail/supportPrdDetail.do?menu=SP06&prd_ia_cd=&prd_mdl_cd=&prd_mdl_name=DMR77LHS

hti had athe same problem, and the fuse fixed it. it turns on now,

you can get to the fuse casing, small tube about 1.5 inches , black, by flowing the electrical line to the, inside , or the under carriage, on the side of the bottom of the unit.
15 amp 250 volt at radio shack.

Hi,
The main PSU is part of the control board. You may be lucky to find an aged fuse to replace, but it's more likely a power transistor that's fried.

Unplug and remove the control board to see which bit's toasted. Chances are it's cheaper to replace the control board - but check the probable cause - the motors are not short circuited.