Question about GE JVM1440 Microwave Oven

1 Answer

HV diode producing resistance of 10 ohms.

Just tested the diode, transformer, capacitor, and magnitron in my GE jvm1441bh. Everything checks out but the diode.

The gallawa website says to set the ohmeter to read ohms @ a scale of R X 10,000 or higher. My meter just has one setting of 4000 ohms, which I suspect is just an auto range of 0 - 4000, so I'm afraid it isn't capable of reading resistances in the 50,000 - 200,000 range.

If that's the case is my multimeter simply providing a bad reading for the diode? It's reads 10 - 11 ohms across the anode/cathode.

Sorry for the ignorance, just not too familiar w/multimeters.

Posted by on

  • 1 more comment 
  • dave_demaree Mar 07, 2009

    Appreciate the reply bob. Just a quick question.

    The gallawa site says that as long as you have a mm that utilizes a 6 volt battery or greater, you're ok. Mine uses a 9 volt battery.

    The website doesn't mention setting up a test circuit, just attaching the probes to either end of the diode and reading resistance. Is that not correct?

  • dave_demaree Mar 08, 2009

    Thanks for the clarification Bob. This microwave is only 3 years old, so I will have to use your method. To clarify, are you just hooking the diode in series with one of the battery terminals, then attaching the mm probe to the free end of the diode, and attaching the other mm probe to the free battery terminal?

    I tried that and I got a reading of 9.3 v both ways. When hooking the diode in parallel with the battery terminals, I got a reading of 5 volts one way, and three volts when reversed.

    Would this denote a faulty diode?

  • jpal012 Mar 26, 2009

    I have a jvm1440 ge microwave that doesn't heat the food but everything else works.The capacitor did not spark when I went to discharge it.I used your diode test with the 9volt battery . It tested good. The fuse also tested ok. I would like to test the transformer but I havent found a good test method yet also its pretty buried in the oven. If you know a good transformer test I would definitly be interested. Thanks


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Master
  • 267 Answers

You cannot check a microwave diode with just a mutli meter . you have to make a test jig take a 9 volt battery and a meter with dc volt scale set up the meter just like you would test a 9v battery .with me so far ? now remove one lead from the battery and insert the diode between the battery and the test lead .......take a reading . now reverse the diode take a reading ........ i just tested a diode before writeing this and this is what i got my battey volts where 9.2 v whith the diode inserted i got 7volts . reversing it i got .02 volts dc . a diode is a one way valve and mine is good because it passed curent only one way ...yours should be about the same ....... if you understand this please leave me 4 stars ! i even went out in the shop and tested a diode for you just to make sure my answer was correct

Posted on Mar 07, 2009

    BOB BROWER Mar 08, 2009

    there was a change in diode type . i for got to ask you how old your microwave is . if your microwave was made before around 1985 you can use the meter with the batterys inside . if it was bade after around 1986 its a very hv diode and will require the 9v battery test jig ..... there where 3 changes to the diodes 1966 to 1972 test with any meter 1973 -1986 any swing meter with 6 v battery (do not use digital) 1986 to present must use special equipment or homemade eqipment with 9v battery or higher and a dc volmeter ....... hope this helps , sorry i did not know you had an older microwave , i dont see them anymore in my shop and forget there are a still a few out there .... good luck

    BOB BROWER Mar 08, 2009

    the diode is in series with one battery connection and a meter lead eather one will do . then turn the diode over , you should be reading the battery volts through the diode


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Why is my Sharp Microwave Drawer KB-1614LS not heating?

You should check for 3 volts on sec coil supply for magnetron but do this check with the hv capacitor and hvr disconnected if 3volts is present , most probably your magnetron is deffective, replace it with the same type

May 13, 2014 | Sharp Microwave Ovens

1 Answer

JEM 31 is not heating

Sounds like you have a bad transformer. Magnatron should check less than 1 ohm (with wires unplugged). Diode should check resistance one way and open the other. Must have a proper diode checker for this. Check resistance on the capacitor (make sure it is discharged first). Resistance should come up then back to open, reverse and same thing if cap. is good. Check resistance on transformer windings.

Nov 05, 2007 | GE Spacemaker JVM1640SJ Microwave Oven

2 Answers

Blown fuses

Well you certainly have done a lot of work on a microwave that is not worth the effort. When fuses blow and destroy other items ,it is time to junk it and up date. I have found that when something like what happens 9 times out of 10 it will be the magnetron or transformer either of which will be more than 1/2 the cost of a new machine.

May 18, 2013 | Microwave Ovens

2 Answers

Ge microwave mod. #JVM1851BH06. i ohmed the capicitor 2 meg ohm and increased to 11 meg ohm. I also measured the diode which i believe branches off one leg of capacitor it shows open resistance O.L. both...

I'd say your diode is bad but your capacitor may be good. You need to test it further - as described below.

In order to get reliable measurements to make a determination about the condition of the components, each should have at least one lead removed from the circuit. If not, your meter will read the through the rest of the circuit - and not be limited to the diode or capacitor under test.

To check a diode: Set the meter to to the lowest scale (Rx1) and touch black (-) probe to the cathode of the diode (the end with a band around the diode body) and the red (+) to the anode lead to reverse bias the diode. The meter should indicate "OL" or high resistance. Reverse the meter probes so that RED (+) is on the cathode lead and black (-) is on the anode to forward bias the diode. The meter should read a very low resistance - approaching 0 ohms. Diodes should conduct in one direction only - and the other is should look "open" If it conducts or is open in both directions, it is defective. Zener diodes can be checked with an ohm meter, but need a variable voltage supply and are required to be in a circuit (instead of out of circuit like a standard diode) for accurate testing. A link to zener diode testing here.

To check a capacitor: Set the meter to the lowest scale (Rx1) and touch probes to capacitor leads. The meter should indicate "OL" or high resistance and show steadily decreasing resistance before increasing to OL or high resistance again. Swap probes from the meter on the capacitor leads and "OL or high resistance indication should change to an even lower amount of resistance thas before before returning to "OL" or high resistance indication. These are test result characteristics of a good capacitor under test.

I hope this helps & good luck! Please rate my reply - thanks!

Jan 27, 2011 | GE Profile Spacemaker Over-the-Range...

1 Answer

Fan works,all controls work,---loud motor noise right side by transformer and does not heat anything.


Depending on your technical skills , there are basically 4 components which you can check than normally cause this type of error in a microwave.


Firstly , check to see if your microwave is fitted with a fuse. This will normally be located inside the casing and it is not very common for a microwave to have a fuse , so don't worry if you can't find one. If you are in doubt , let me know and I will look up to see if there is a fuse for you to check.

Open the casing of you microwave and look at the back right of the unit for the following.

HV Diode is located near the power supply and is identified with a symbol like in the picture below.


Check the diode for physical damage like a crack , bulge , burst or burned smell as they normally fail physically. To test , set a multimeter to test resistance at 10k ohms and test. A normal diode should read 50-200 k ohms. If not , replace the diode as it has gone. Remember that the polarity is important , so test it both ways (or put positive to anode of diode)

Next component to check is the HV Filter Capacitor. This component is a big circular steel tube on the board/mounted near the HV diode.
Locate and remove any leads going to the capacitor AFTER DISCHARGING THE CAPACITOR.

Now , set you multimeter to resistance again to the highest available setting. Now put it onto the terminals for a few moments (Should read infinite) and then switch the leads around. The reading should go to almost zero and then go back to infinite. Also test between each terminal and the casing (if not covered in plastic) and this reading should be also be infinity. This test might not work if your multimeter is digital and has a very high latency. If it's a good quality multimeter , it should work fine.

Also inspect the capacitor for bulges , leaking , a strong burnt smell or a crack and replace if any of the test fails. These capacitors are designed to fail at the top of the capacitor where steel is visible , so check here especially.

If neither the Diode or the Capacitor is defective and there is no fuse, by process of illimination , the only thing left is the Magnetron. Depending on how expensive your oven was it may not be worth replacing as it's a expensive component. In your case , it would cost about $50-$100 for the magnetron , so you might just want to buy a new oven.

Most of these components can be found or ordered at radio shack (diode and capacitor) or most any other electronics supply store or (magnetron). If not , contact the GE directly.

Feel free to ask if you need more info or have any questions.

Jul 02, 2010 | Amana ACO1840A Microwave Oven

1 Answer

Just replaced the magnetron in my Panasonic NN-S543BFR. I still don't get any heat from my oven. Everything works as set but still no heat in oven. Need suggestions on repairs.

When you say "Everything works as set" do you mean the microwave appears to function properly, but then doesn't heat?

If the magnetron is new, then the magnetron must not be receiving the required high voltage (2000V or more) from the HV circuit. Make sure you've got 120V to the PRIMARY (don't attempt to measure secondary voltage of the HV transformer without special equipment) of the HV transformer. After that check the HV capacitor and diodes. If these components test OK, then either your HV transformer is bad or your new magnetron is faulty. My experience is that the problem is usually in control circuitry, preventing 120V to the HV transformer, or opens/shorts in the HV components (diodes and capacitors).

Mar 15, 2010 | Panasonic NN-S543BFW Microwave Oven

1 Answer

Ge jvm 1653 won't heat

You've got a problem in the microwave circuit, which could be one or more of the following components -

1) HV diode
2) HV Capacitor
3) HV transformer
4) Magnetron

I am leaning to the diode, but it would take further investigation to determine for sure. Diodes are cheap, as if the capacitor, and replacing those first would not necessarily be in vain if it turns out to be the transformer or magnetron. And I would be most inclined to say it's the magnetron before I would think transformer.

Reply back what you find or if you have more questions.

Feb 04, 2009 | GE Microwave Ovens

1 Answer


hi i am suggesting that it is probably the magy as the res to grndis a bit low and therefore loading the sec supply down , just a thought
cheers grant

Oct 23, 2008 | LG LRM1250 Microwave Oven

2 Answers

Microwave oven problem

If your microwave is doing everything, but heating it could be any one of the following components: Magnetron HV Capacitor HV Diode HV Transformer This network works in conjunction to produce the high voltage required to heat. Taking live voltage measurements is dangerous and not recommended. You can, however, do resistance checks on the components with the unit unplugged to see if you can isolate the problem any further. The HV Diode should be mounted somewhere on or near the HV capacitor and will read an open in one direction and a relative short in the other. If you put a meter on the capacitor you should see a varying resistance as the capacitor charges and discharges. There should should be a wiring diagram inside your control panel with the resistance readings for the primary and secondary windings of the transformer and the filament of the magnetron. In a nut shell, you probably have either a bad magnetron or a bad diode. Those are the two components that fail more frequently. Of course, double check all your interconnecting wires too. Good luck and let me know if this helps.

Jun 22, 2007 | GE JVM1660 Microwave Oven

Not finding what you are looking for?
GE JVM1440 Microwave Oven Logo

Related Topics:

845 people viewed this question

Ask a Question

Usually answered in minutes!

Top GE Microwave Ovens Experts

William Miller
William Miller

Level 3 Expert

8865 Answers


Level 2 Expert

224 Answers

D. E. Hev

Level 3 Expert

1132 Answers

Are you a GE Microwave Oven Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides