Microwave Oven Capacitor Testing

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • genuineguy
    Member
    • Sep 2015
    • 46
    • india
    #1

    Microwave Oven Capacitor Testing

    Hello Experts
    Need help with my experiment to test a Capacitor from microwave oven

    Its a High voltage capacitor. 1mfd, 2100V AC.

    A DMM test across its terminals show infinite/open resistance.

    The capacitor has a 10Mohms shunt resistor internally.

    1. Connected 100w bulb in series to the capacitor. AC supply 230v connected. The bulb did not light up. This proves the capacitor is NOT shorted

    2. Connected capacitor in series with a diode and 10ohm, 10W resistor. Connected AC supply 230v. I was hoping DC voltage reading of 300+ volts across the capacitor, because the capacitor will charge to peak of 230v rms and hold it there... However, DMM shows 100V DC.

    Any corrections to my experiment #2 ? Is the capacitor leaking ?
    Tags: None
    • bestsystem
      Senior Member
      • May 2011
      • 59
      #2
      Re: Microwave Oven Capacitor Testing

      1. May be shorted with higher resistance so the bulb cannot noticeably light up

      2. Calibrate your dmm or get an extra one to cross check

        Comment

        • eccerr0r
          Solder Sloth
          • Nov 2012
          • 8665
          • USA
          #3
          Re: Microwave Oven Capacitor Testing

          In experiment #2, what if you tried a known good capacitor or what if there's no capacitor there at all, what is the voltage? Just want to also rule out a weak diode...

          The reactance of a 1uF capacitor at your line frequency is a bit over 3K ohms. I'd expect a good capacitor to dimly light up a 100W@230V lamp with a 230VAC source in series. You really need a DC voltage to truly test leakage.

          Right now given the information seen here that capacitor is questionable but need to confirm your testing apparatus first.

            Comment

            • genuineguy
              Member
              • Sep 2015
              • 46
              • india
              #4
              Re: Microwave Oven Capacitor Testing

              I connected the diode in series with the 100w bulb. The bulb did light up, it was flickering and somewhat half the brightness than a normal 230v connection. I recognise this light as I have connected diodes in the past to 100w bulb. so i am concluding the diode is good.
              I also used a 12V battery to connect to the diode and test using DMM. The forward reverse test did succeed.

              So , the diode appears good to me.

              I am doing this experiment to confirm my capacitor is good or bad. I do not have a new capacitor. Looks like I have to go buy a new one.

                Comment

                • genuineguy
                  Member
                  • Sep 2015
                  • 46
                  • india
                  #5
                  Re: Microwave Oven Capacitor Testing

                  Turns out the capacitor was indeed faulty. I got a new one and the microwave oven is working. I had to replace the magnetron too. Hopefully this sustains and does not fail again.

                    Comment

                    • PeteS in CA
                      Badcaps Legend
                      • Aug 2005
                      • 3576
                      • USA, Unsure of Planet
                      #6
                      Re: Microwave Oven Capacitor Testing

                      Magnetrons and traveling wave tubes are vacuum tube and have a finite life due to the heater, which is necessary for operation. They also have a high operating voltage, often several thousand volts (the TWTs I worked with at a previous employer had a cathode voltage around -4 KV).
                      PeteS in CA

                      Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
                      ****************************
                      To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
                      ****************************

                        Comment

                        Previous template Next

                        Related Topics

                        Collapse
                        • valvashon
                          Toshiba EM131A5C-BS microwave oven- noisy EE16 2.7 mH inductor
                          by valvashon
                          This poor microwave oven was purchased by my former employer in 2019 (it's a 7/2018 build) and lasted for about 3 months before making a terrible noise when in use. I determined that it was the main transformer and contacted Toshiba. They asked for a picture of the cord cut in half and the serial number, and then credited my boss' credit card. Rather than sending it to the e-waste, I bought a transformer on eBay and thought I'd try flipping it. Discovered that used microwave ovens aren't worth much but in for a penny, in for a pound as they say. It sat in my basement getting kicked and shoved...
                          02-20-2024, 10:38 AM
                        • goodpsusearch
                          Daewoo microwave oven repair
                          by goodpsusearch
                          One day my microwave oven stopped heating.

                          It would turn on and rotate the plate but no heat.

                          I removed the cover and checked components with digital multimeter.

                          Found that the high voltage fuse was blown.

                          This is not the AC fuse, if the AC fuse was blown then the oven would appear totally dead.

                          Then I tried to find replacement fuse on local electronic parts stores and this specific value was not available so I got the closest I could find.

                          I replaced fuse and tried to heat up a glass of water.

                          Strange noise...
                          01-24-2021, 03:56 PM
                        • tmhobadcap
                          Can a microwave oven be used to reflow solder joint?
                          by tmhobadcap
                          I heard somebody suggested a way of repair faulty led light bulb which I have never heard of. The way is to put the led light bulb inside a microwave oven and turn on the microwave oven for a few seconds. He said that faulty led light bulb is usually caused by poor solder joint between the led and the pcb. Putting the bulb inside the microwave oven for a few seconds will heat and reflow the solder joint making it works again.

                          Is that possible? I do not want to try this unless I have a spare microwave oven.

                          (I do not mean to suggest somebody to try this. It may be...
                          10-30-2020, 08:38 PM
                        • Prolog
                          RTX 3080 FE Identifying capacitor
                          by Prolog
                          Hi people, I hope this is the correct spot to post this, I'm new to the forum.

                          I have an RTX 3080 Founders Edition which has a burnt up capacitor (it was in parallel with another capacitor which appears damaged too), so I am hoping to be able to identify the capacitor values and order replacements.

                          I hope these photos make it clear which component I am referring to:
                          (yes, the soldering is a bit botched from removing the blown one, I know)

                          I have found the board schematic (attached), but there does not seem to be a boardview available. I have never...
                          12-01-2024, 08:27 PM
                        • chth96
                          If I replace with inferior capacitor, Is it No harm to other IC components at all?
                          by chth96
                          I replaced some capacitor which is located on optical pickup pcb which is shown in the table below(PCB #2).Because it have been out of order.
                          Now,It works very well,But I just have found that all caps (6svpc100my and other part number as well) ,which is shown in the table below, has ultra-high ripple current spec.
                          It is not able to obtain any capacitor which can be a substitute for this ultra-high ripple current nichicon capacitor.
                          So I replaced it with samxon and rubycon's general capacitor(GP,YXA series).
                          I know that these capacitor will not last as long as nichicon capacitor...
                          12-22-2023, 04:34 AM
                        • Loading...
                        • No more items.
                        Working...