Damn... I really wish you were still making videos! Great stuff man

Poultonm; thanks for your video, it was very illustrative, but I was wondering about what you said in the vid description; do you think replacing the high voltage transformer with a cooper loop will do the same job as a induction heather or it requires anothers modificions ? Thanks in advance for your comments.

Great tutorial Mr Poulton. I got a panasonic inv to run after watching your video. I don't have to tie the fdbk signal to common through a 1k resistor on my unit. This signal appear to go through an optocoupler output . Maybe other inverters are different. Tks for the video, good job !!

The control circuit is at least as simple as anything you could reasonably want to power with this thing... It's about the simplest project possible using an integrated circuit. There are literally dozens of different ways to build it that would work. All you need is a square wave with the proper characteristics. A quick google search will turn up plenty of possible approaches. I just googled square wave oscillators and PWM circuits to find a solution that would work with parts in my bin.

great info thanks. Do you think I could rewind the primary to take 12v inputs? so I can run microwave on 12v.

can anyone enlighten me on the 555 timer circuit for this as I’m I’m new to electronics ,correct me if I’m wrong but 555 timer only can go to a minimum of 50% duty cycle so how did he manage to reach a 43% duty cycle on a 555 timer, is there something I’m missing?

can you show us how to bypass the duty cycle circuit? is it possible to simply power the inverter with the microprocessor board or control panel of the microwave

@Alex1M6 I'm sure it'll be awhile until the iron transformers go away. These are still only in high-end microwaves. While these are flyback mode converters, the transformer doesn't have much in common with a CRT flyback except a gapped ferrite core. The turns ratio is about 10x lower, and it's made for much higher power at lower voltage. Peak secondary voltage is about 4.5kV. And unlike a CRT flyback, these things will straight up kill you and set you on fire. Just like a MOT.

If I ever find one of these thrown out somewhere, I would re-wind the output transformer and use it in a switch-mode power supply project.

Hi, I want to do something similar, but instead of using the inverter ps, I'm trying to use the oven with the old transformer, capacitor and diode just to eliminate the inverter ps. I connected a 1k resistor between orange and brown and it worked, but only for 23 seconds, then shut down. Have any idea what is going on here? Thanks.

Awesome tutorial Poultonm: would you mind emailing me through a quick diagrame of the control wires conneted to the 1K resister!! not to sure of which 3 wires to connect it to. Kind regards. Terrt

Hi good day i have the same microwave but no display on controller board and i saw smoke coming from microprocessor on controller board , can i set up a seperate controller board using the 555 timer ic to turn on the high voltage circuit ? Can you please assist me with the shematic diagram.thank you.

Sure! As long as you want your radio transmitter/Tesla coil/induction heater/other contraption to be programmed and operated like a microwave oven. I can't imagine that would be very useful though.

poultonm I rewined my MOT it is 18 volts maybe 20 amps how do I vary it from 1 to 18 so I can control my induction heater?

Would an RC servo tester generate the right PWM signal? That would be a really easy and cheap way to control it if it does, it has a little dial to set the PWM value. I got one of these newer MOT units recently and couldn't for the life of me get it to work, not knowing about the PWM thing, so I scavenged it for components but I'll keep an eye out for another one to experiment on, being able to adjust the power level would be great, it would have worked well for a capacitor bank charger I'm putting together. These do come with some excellent components though, I got a great ferrite core, a good length of fine magnet wire, a few feet of Litz wire, a mosfet, a 1000V bridge rectifier with heatsink, a bigass resistor, a couple small capacitors and a few other odds and ends, at least it wasn't a total loss. Now I'm using the 1KV rectifier on my capacitor bank charger that's using a regular iron-core MOT connected to a 500 Watt variac to dial in the 475 Volts I need for the caps, with a couple light bulbs in series on the primary to get my current way down. It's going to be fun, the bank has nineteen (would have been 20 but one was bulging😒) 422uF caps at 475 Volts each, with a total capacitance of 8,000uF so each pulse will be just shy of 1KJ.

Do you know what would be the reason of sparking inside the inverter board.

Hi, I have seen your Utube demo for Microwave oven Inverter hacking - the new MOT, and pleased to watch the very informative illustration. I would like to know whom and how should I contact to clarify a problem about my Inverter Grill M.W. No.NN-GD371M. Thank you JP

Hello Dear Inverter Enthusiasts I have been designing a controller for a National inverter board with two IGBTs and I have not yet concluded to the exact timing for the duty cycle because I do not know the transformer and magnetron’s parameters. Any suggestion to tackle this problem would be highly appreciated. Thank you for taking time to read this script.

Where can we buy the parts of microwave in WINDHOEK NAMIBIA?

This is a very informative video. Thanks for the hack. I have one of these inverters from a Panasonic NN-H665BF microwave. I also want to repurpose the timer controller from this microwave on a separate project. However, the 3 lines from the main PCB to the inverter and/or the line voltage connections to the inverter are required somehow to feedback to the controller that the inverter is powered up. If these lines are not completed, the timer always stops after 3 seconds. Do you have any idea how to bypass this function on the timer/main PCB? I thought it might be that the orange 110 hz square wave line needs to be simulated by a custom 555 timer circuit?

Perfect

I would assume it performs very poorly, probably by self-destructing. It might survive since it's a constant-power regulator, but that would be well outside its normal operating parameters so I would not expect it. The results will not be as impressive as you hope, since iron core transformers handle very high peak powers that make impressive arcs. This thing will never push much more power than it's designed for.

how did you find the specs for the wires/pinouts?

can you show it in action? (arcing)

@poultonm thank you for the video,, subbed

There are none available. That's why I reverse-engineered it. As far as I know, I'm the first to publish this information publicly.

any chance you can provide the schematics for that 555 timer circuit?

Hi friend, Excellent work! I came across your KZfaq just lately and am enjoying them thoroughly. Thank you for your skillful engineering work. I think +5V at pin 3 after the AC power switch on will work. Don't you think? Somebody overcame the cutout problem you experienced by modifying the PWM TTL signal input . Thanks again Nwin

I think iv found a way to bypass the square wave safety and get 100% output by soldered over the switch

Is there any way that I can simulate the pwm to get the timer control board up and running?

Many have asked, but could you please post a schematic of the 555 circuit? Im at a complete loss on what values to use for the capacitors and resistors.

Its a shame they are doing this and getting rid of the MOT designs, although at-least it gives high voltage junkies like me a new source for flyback transformers.

What voltage must the 220Hz square be at? Also, does it have to be strictly 220Hz, or could it be off a little?

As a non electrician I'm surprised you said the Inverter produces microwaves, did you mean with the magnatron attached?

How would I make a fractal woodburner machine from this though?! I have a 1300 w microwave for this one found out that it's not the old one 😂 help!

Any one knows how to reduce the voltage output of microwave inverter instead increase the Amperes of its current for possible inverter welder projects

quasi Flyback, It turns off the igbt when the voltage is lower..... IT IS A FLYBACK

This would not be a good choice for an ozone generator. Ozone generators require high voltage at low current, and total power much lower than what this is designed for. A flyback transformer would be a better choice. This thing does not produce enough voltage, and is far too dangerous for that application.

Could you just control it with the time control board that came with it?

tesla community saved!

So basically unless you have the right equipment an your a rocket scientist these things are useless. Gee thanks

So the term "inverter" is a lie, and these actually use the opposite (a rectifier) to work. And pulsed DC is not the same as AC. Taking AC and turning it into DC is exactly the job of a rectifier. There ought to be a law prohibiting deliberately misleading nomenclature. Think about it: an inverter is what creates AC electricity. To apply an "inverter" to an AC power source is worse than pointless. I think I'll manufacture a switchmode power supply and call it a "Transformer®". 🙄