• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake

ME18H704SFS - Sudden Case of Intermittent Power Outage

LanceH

Premium Member
Joined
Jan 11, 2018
Messages
6
Location
NC
Model Number
ME18H704SFS
Brand
Samsung
Age
1-5 years
Kind of frustrated with Samsung Overhead Microwaves at this point... my first one lasted only 5 years and died suddenly, but an almost identical looking new model (ME18H704SFS) was on sale at the time, so bought it and swapped it out a little over 3 years ago. Just a new months past the end of the 12 month warranty, the Magnetron craps out. That's at least covered for 5 years, but had to pay a good sum for the tech to come out and replace it. Now jump ahead about 2 years of trouble-free operation and we woke up the other morning to find the unit dead... no power to the display, no light inside when you open it. D-E-A-D...

I checked for a bad breaker (looked good, switched off and back on just in case) and checked the plug... verified the outlet still had power with another device... all good there, so plugged it back in.

Still dead...

No time to mess around further, we went on to work/school and didn't mess with it any further that evening. Still dead.

The next morning... awoke to find the power to the display back on. Opened the door... there was light. Closed the door, Reset the clock... lasted about 10 seconds and boof... dead again. WEIRD...
No one touched it for the rest of the day.

This morning... awoke to fine the power back on once again. Opened door... there was light, closed the door. Instead of resetting the clock, I took a damp paper towel, threw it in and cooked it for 20 seconds
and got steam. Opened it... hot to touch, put something else in, cooked for another 20 seconds. All is well... power staying on. Did not reset the clock... left for work. Curious to see if it is still on when I get home,
but obviously something is going wrong inside to cause this weird behavior as I suspect it will be dead again before the end of the day.

Any tips on what could be wrong and how to go about tracking down the cause?
 

LanceH

Premium Member
Joined
Jan 11, 2018
Messages
6
Location
NC
Update, still working when I came home. Set clock, test cooked for a few seconds.. No issues. Next day, still working but afraid to try and cook anything major in case it craps out in the middle of it. No idea what went wrong or when it could happen again.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
33,462
Location
Murray, Utah 84107, United States
Intermittent problems with a microwave can be difficult to diagnose. It sounds like a loose connection on the noise filter or control board. Since everything was dead (no lights or display) that would narrow it down to either the noise filter or control board and wire harness connections between the two. You can check for a loose wire connection or a burned wire but unfortunately you're probably going to need to wait until it dies again before you can find the problem.
 

LanceH

Premium Member
Joined
Jan 11, 2018
Messages
6
Location
NC
Thanks, next time it happens I can check. Are there any pictures or diagrams showing where these are located available for this model?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
33,462
Location
Murray, Utah 84107, United States
The control board is behind the display panel and the power cord connects to the noise filter if that helps.
 

LanceH

Premium Member
Joined
Jan 11, 2018
Messages
6
Location
NC
It ran perfectly for 3 days and then poof... without warning, turned off again for the past 2 days. Since I'm home due to the snow, finally had time to take the front cover off and look and unfortunately, I don't see anything that resembles burnt, damaged or even loose power wires. I could try to disconnect and reconnect a few, but I'm not sure where I would need to touch to get the energy out of the capacitor and I don't want to touch anything by mistake and get lit up... any advice?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
33,462
Location
Murray, Utah 84107, United States
It's difficult to tell anything from pictures unless it's obvious. Your capacitor has a bleed resistor connected to it. The best way to drain a capacitor is to use a long screwdriver. Hold the end of the screwdriver on one of the capacitor terminals and touch the screwdriver shaft to the frame. Check for 120 VAC supply voltage at the filter (with the two ceramic fuses) and check for 120 VAC output to the control board. Check for 120 VAC input to the board. I don't have a wire diagram for that model so I don't know where that is on your board. If you can post a copy of your tech sheet it would be helpful. I'll see if I can find it online but so far no luck.
 
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