Why does a microwave oven need 12 relays, how many high voltage circuits are there in an oven? light? turntable? magnetron? grill? bleeper alarm? 12 relays seems excessive.
I blew up 3 of the tiny diodes trying to test the relays. I did get the relays tested though. Wish I'd known the correct polarity to apply before I tried it though. Where can I get those tiny surface mounted diodes?
Im trying to troubleshoot my relay on a refrigerator pcb....the coil side of the relay is measuring 12 volts on one side and 6 volts on the other when the machine is running...im trying to track down if my issue is not the relay or not but i dont know how much voltage the other side needs to be....if its supposed to be both 12v...12v and 6v (like it is when it runs) or 12v and 0v (ground voltage)
I see diode symbols printed near the relay coil contacts. Often, diodes are placed in parallel with the coil to absorb back EMF when the relay is de-energized. If you attempt to energize a relay with your 9 volt battery, you need to apply the voltage such that the diode is reverse biased. If you apply the voltage with the diode forward biased, the current will go through the diode and not through the relay, giving a false negative. Maybe this is why you said some relays were "polarized."
I blew up 3 of the tiny diodes trying to test the relays. I did get the relays tested though. Wish I'd known the correct polarity to apply before I tried it though. Where can I get those tiny surface mounted diodes?
I just replaced a GE microwave over stove and kept the broken one being only two years old. it had no power to touch panel or anything else so i checked the thermo fuse and it was bad so i temporarily jumped the wires and plugged it back in and everything came back on. the only problem is the exhaust fan comes on and won't turn off. even after at least an hour or so. i just watched your video on how to test and replace a microwave relay ,i was very impressed at how well you explained how to test and replace it. what do you think it could be one of the relays are the problem. i did take out the three door switches and checked for continuity and they all checked good.
Hey Johnny. I would not be surprised if the fan is the reason the thermo fuse burnt out. If the fan was stuck on the current draw could eventually cause the fuse to go. So what can cause a fan to get stuck? It is very likely there is a fan relay.
@@jebadiaha I checked all the relays on the board like you did in your video , bug they All tested good Then I took all three door switches out and opened the up and cleaned the contacts, only one was tarnished Put them back in and did a continuity test on each switch while opening and closing the door, all worked fine. Also I noticed the nite lite is on also and won't turn off or on high.and fan stays on low speed still.
Never mind about the fuse it is bad , supposed to have continuity . I got mixed up with that . So I'll just put a jumper between the two wires temporarily just for now till I figure out why the fa and under neath light stay on
The desoldering braid: Don't hold it directly with your fingers; it will conduct heat from the iron and burn your fingers. Better to hold onto the braid container with only as much braid coming out as is needed. Also, advise using flux on the braid to improve the wicking action. Good that you opened up the bad relay to show the guts, but you didn't show what was wrong. Burned contacts?
I have a fair new GE microwave that after a storm when plugged in the surface lights keep flashing and and the display is gone and make a click noise when the door is closed, I’ve replaced the thermal fuse and did not helped. Some one knows if just replacing the control board is going to resolve the issue? Any comments will be much appreciated. Thanks
Wow I had to go all the way to12:20 to find out what the issue is that you were trying to repair. I have dim lights or no numbers on my microwave display, but the dots and dashes blink. Most people are saying it's one of the caps on the PCP board, or the ribbon wire. Glad I stayed until the end of the video to find out what the heck you were trying to fix . Nothing in the description either.
Anyone have ideas on what causes relays to fail in the first place (aside from lots of use)? I replaced 3 in my microwave convection oven and all failed within just a few cycles. Thinking of replacing the whole board, but would love to identify the root cause first. Capacitor and switches all check out ok.
I really don't know. But if 3 failed and the replacement parts failed too, then it sounds like the board is the root cause. I dissected one and note that the wire coil is very thin gauge wire. If too much current goes in, the wire could heat, melt the insulation, and short circuit. I am not sure how to prove this theory.
@@jebadiaha Thanks for the reply... the slow-fail nature of the new relays seem to fit that theory - there was heating for a few cycles then nothing. Given that a replacement board costs more than a new microwave (!?!) I think I now have a project microwave while my wife gets a new one. Appreciate the insights.
With my test I used a 9V battery to open/close the relay. But read the spec on the relay itself so you don't use too high voltage and melt a good relay.
Hi! Nice video! Recently I found problems with the relays controlling the magnetron power supply. These relays have a controlled contact connector in the top, blade connectors. On the pcb is only the coil supply circuit. Those relays contacts get "welded", the magnetron circuit gets power all the time overheating and damaging the magnetron. I have replaced the relays with new ones, I have replaced the magnetron with a new one but the problem appears again sometime. I try to figure what causes to weld those contacts. Is it the relays contacts quality or does one of the components in the magnetron circuit getting older, contribute to a higher than normal start current welding the contacts? Every time, after the replacing of relays and magnetron, the microwave runs normally, being able to heat. Some time the magnetron power relays contacts gets welded during the test period. That makes me troubled. I can't figure out what is causing this. If you have ideas let me know.
This is beyond my skills. Your higher than normal current going through the relay seems plausible. Perhaps some up stream current regulating bits are malfunctioning. Resistors usually fail open (no current) so I would think something else. I know that feeling of wanting to figure it out and fix it. But sounds like you are a few dollars in already. Sorry to say it might be time to buy a new microwave so that you don't throw away good money.
@@jebadiaha Thank you for answer! I work in hotel industry and I have 227 microwaves, ge, 5 years old. The problems that I mentioned happened sporadically. I'm still curious to find the cause just because I can't just quit ...
Sir my microwave keeps on all time but no heating. When I open door then it turns off. When I press keypad start button it works to heat. But won't stop unless I open the door. What should I do?
This sounds like some very difficult problems to troubleshoot and not only related to the content of my video (relays). If I were you I would try to find a replacement control board. However this is typically an expensive part making it a better decision to replace the microwave instead of trying to fix it. If the parts cost more than 50% of a new microwave and you are not confident this will fix the issue, then it is better to replace the microwave. Repairs are only worth it if 1) you ARE confident it will fix the issue AND 2) the cost of parts is less than 50% of the cost of a new microwave. If you are NOT confident (in your case - I imagine you are not confident. I am not) then put a threshold on what you are willing to invest in parts to TRY to repair it. I would say invest no more than 10% of the replacement cost. Hope that makes sense.
@@Omcsesz That's what happens to mine! When connected to the source, magnetron is ON, light OFF, plate OFF....and when I close the door the magnetron is still ON, light ON, plate ON, heating at full power and it doesn't allows to change intensity. When door is open, light is ON, plate OFF, magnetron OFF. I can't leave it connected because magnetron hungs up in ON at full power. I tried to clean some dust with blowing some air into a tiny gap in the metal cover and the edge (where the buttons are), and suddenly when I closed the door, silence. It was normal again 😍 Same happened last year and didn't remember I was blowing some air with my mouth and ''fixed'' it. But I don't have a clue on what's really going on and how to prevent it. Sure it's dust and dirty stuff that accumulates there but don't know what to do against.... Any ideas?
Nice video -I feel my oven relay is faulty -I am having the same problem would check the relay before buying a new board ite $78 and a relay is $1.50 tks
That may not be a problem. I think that could be correct under some circumstances. Many types of electronics have a common ground. The relay has a electromagnet, that when energized, will close the switch. one side of the switch may be to ground. Also one side of the input pins (as I called them) that energizes the magnet should be ground/common.
So clear and logical. Thanks so much for a wonderful resource.
It was great help to fix the relay on a GE microwave logic board. Thanks
What are those two big relays in the middle? What is their functionality?
Thanks for your amazing video
HI
DO YOU KNOW THE PART NUMBER FOR THE SUPPRESSION DIODE ACROSS THE COIL ON THE RELAY (SMT DIODE ON PCB BOARD)
Why does a microwave oven need 12 relays, how many high voltage circuits are there in an oven? light? turntable? magnetron? grill? bleeper alarm? 12 relays seems excessive.
I blew up 3 of the tiny diodes trying to test the relays.
I did get the relays tested though.
Wish I'd known the correct polarity to apply before I tried it though.
Where can I get those tiny surface mounted diodes?
Yes , I can set the clock and I can heat up with it, I heated a cup of water and everything worked thanks for your feedback !
Im trying to troubleshoot my relay on a refrigerator pcb....the coil side of the relay is measuring 12 volts on one side and 6 volts on the other when the machine is running...im trying to track down if my issue is not the relay or not but i dont know how much voltage the other side needs to be....if its supposed to be both 12v...12v and 6v (like it is when it runs) or 12v and 0v (ground voltage)
How do you test the relays that have the 2 connectors going in through the other side?
I see diode symbols printed near the relay coil contacts. Often, diodes are placed in parallel with the coil to absorb back EMF when the relay is de-energized. If you attempt to energize a relay with your 9 volt battery, you need to apply the voltage such that the diode is reverse biased. If you apply the voltage with the diode forward biased, the current will go through the diode and not through the relay, giving a false negative. Maybe this is why you said some relays were "polarized."
I blew up 3 of the tiny diodes trying to test the relays.
I did get the relays tested though.
Wish I'd known the correct polarity to apply before I tried it though.
Where can I get those tiny surface mounted diodes?
Perhaps a resister in the mix may prevent the frying of diodes. Good video.
sir i changed Relay but all things working but not Heating ??? help pls
if Both wires of Relay r voice versa It matters or not ???
I just replaced a GE microwave over stove and kept the broken one being only two years old. it had no power to touch panel or anything else so i checked the thermo fuse and it was bad so i temporarily jumped the wires and plugged it back in and everything came back on. the only problem is the exhaust fan comes on and won't turn off. even after at least an hour or so. i just watched your video on how to test and replace a microwave relay ,i was very impressed at how well you explained how to test and replace it. what do you think it could be one of the relays are the problem. i did take out the three door switches and checked for continuity and they all checked good.
Hey Johnny. I would not be surprised if the fan is the reason the thermo fuse burnt out. If the fan was stuck on the current draw could eventually cause the fuse to go. So what can cause a fan to get stuck? It is very likely there is a fan relay.
@@jebadiaha I checked all the relays on the board like you did in your video , bug they All tested good
Then I took all three door switches out and opened the up and cleaned the contacts, only one was tarnished
Put them back in and did a continuity test on each switch while opening and closing the door, all worked fine. Also I noticed the nite lite is on also and won't turn off or on high.and fan stays on low speed still.
@@jebadiahaalso I thought the thermo fuse was bad and it is good, it shows ol no continuity. Is that correct , one lead off while tseting
Never mind about the fuse it is bad , supposed to have continuity . I got mixed up with that . So I'll just put a jumper between the two wires temporarily just for now till I figure out why the fa and under neath light stay on
@@jebadiaha the model is JVM6172sk1ss
The desoldering braid: Don't hold it directly with your fingers; it will conduct heat from the iron and burn your fingers. Better to hold onto the braid container with only as much braid coming out as is needed. Also, advise using flux on the braid to improve the wicking action. Good that you opened up the bad relay to show the guts, but you didn't show what was wrong. Burned contacts?
I have a fair new GE microwave that after a storm when plugged in the surface lights keep flashing and and the display is gone and make a click noise when the door is closed, I’ve replaced the thermal fuse and did not helped. Some one knows if just replacing the control board is going to resolve the issue? Any comments will be much appreciated. Thanks
Wow I had to go all the way to12:20 to find out what the issue is that you were trying to repair. I have dim lights or no numbers on my microwave display, but the dots and dashes blink. Most people are saying it's one of the caps on the PCP board, or the ribbon wire. Glad I stayed until the end of the video to find out what the heck you were trying to fix . Nothing in the description either.
What Brand microwave/model number?
Where did you get the printed flowchart document?
I think it was a GE. I replaced all my appliances a couple of years ago. The flow chart was inside the microwave.
Excellent video.
Thanks for the video. Where can I buy a power relay? They want me to buy the whole mother board for $165. Thanks!
Digikey.com
Anyone have ideas on what causes relays to fail in the first place (aside from lots of use)? I replaced 3 in my microwave convection oven and all failed within just a few cycles. Thinking of replacing the whole board, but would love to identify the root cause first. Capacitor and switches all check out ok.
And, by the way, great video. Thanks for making it
I really don't know. But if 3 failed and the replacement parts failed too, then it sounds like the board is the root cause.
I dissected one and note that the wire coil is very thin gauge wire. If too much current goes in, the wire could heat, melt the insulation, and short circuit. I am not sure how to prove this theory.
@@jebadiaha Thanks for the reply... the slow-fail nature of the new relays seem to fit that theory - there was heating for a few cycles then nothing. Given that a replacement board costs more than a new microwave (!?!) I think I now have a project microwave while my wife gets a new one. Appreciate the insights.
What error code is that? F9? What is your microwave brand?
Thanks for the reply. Mines a Whirlpool and has no diagram.
I will check the relay of microwave oven by how many volts.Please help me.
With my test I used a 9V battery to open/close the relay. But read the spec on the relay itself so you don't use too high voltage and melt a good relay.
Hi! Nice video! Recently I found problems with the relays controlling the magnetron power supply. These relays have a controlled contact connector in the top, blade connectors. On the pcb is only the coil supply circuit. Those relays contacts get "welded", the magnetron circuit gets power all the time overheating and damaging the magnetron. I have replaced the relays with new ones, I have replaced the magnetron with a new one but the problem appears again sometime. I try to figure what causes to weld those contacts. Is it the relays contacts quality or does one of the components in the magnetron circuit getting older, contribute to a higher than normal start current welding the contacts? Every time, after the replacing of relays and magnetron, the microwave runs normally, being able to heat. Some time the magnetron power relays contacts gets welded during the test period. That makes me troubled. I can't figure out what is causing this. If you have ideas let me know.
This is beyond my skills. Your higher than normal current going through the relay seems plausible. Perhaps some up stream current regulating bits are malfunctioning. Resistors usually fail open (no current) so I would think something else. I know that feeling of wanting to figure it out and fix it. But sounds like you are a few dollars in already. Sorry to say it might be time to buy a new microwave so that you don't throw away good money.
@@jebadiaha Thank you for answer! I work in hotel industry and I have 227 microwaves, ge, 5 years old. The problems that I mentioned happened sporadically. I'm still curious to find the cause just because I can't just quit ...
Maybe the diodes in parallel with the relay coil(s)?
Thanks for the great Video.
very good explanation ,thx
Sir my microwave keeps on all time but no heating. When I open door then it turns off. When I press keypad start button it works to heat. But won't stop unless I open the door. What should I do?
This sounds like some very difficult problems to troubleshoot and not only related to the content of my video (relays). If I were you I would try to find a replacement control board. However this is typically an expensive part making it a better decision to replace the microwave instead of trying to fix it. If the parts cost more than 50% of a new microwave and you are not confident this will fix the issue, then it is better to replace the microwave. Repairs are only worth it if
1) you ARE confident it will fix the issue AND
2) the cost of parts is less than 50% of the cost of a new microwave.
If you are NOT confident (in your case - I imagine you are not confident. I am not) then put a threshold on what you are willing to invest in parts to TRY to repair it. I would say invest no more than 10% of the replacement cost.
Hope that makes sense.
You should check the relays. Their contacts can be welded together.
Maybe one of the door sensor switch is bad or the connection between the switch and circuit board is not securely connected.
@@jebadiaha thanks for your kind opinion.
@@Omcsesz That's what happens to mine! When connected to the source, magnetron is ON, light OFF, plate OFF....and when I close the door the magnetron is still ON, light ON, plate ON, heating at full power and it doesn't allows to change intensity. When door is open, light is ON, plate OFF, magnetron OFF.
I can't leave it connected because magnetron hungs up in ON at full power.
I tried to clean some dust with blowing some air into a tiny gap in the metal cover and the edge (where the buttons are), and suddenly when I closed the door, silence. It was normal again 😍
Same happened last year and didn't remember I was blowing some air with my mouth and ''fixed'' it. But I don't have a clue on what's really going on and how to prevent it.
Sure it's dust and dirty stuff that accumulates there but don't know what to do against....
Any ideas?
Nice video -I feel my oven relay is faulty -I am having the same problem would check the relay before buying a new board ite $78 and a relay is $1.50 tks
what if you have continuity between common and one of the connection pins?
That may not be a problem. I think that could be correct under some circumstances. Many types of electronics have a common ground. The relay has a electromagnet, that when energized, will close the switch. one side of the switch may be to ground. Also one side of the input pins (as I called them) that energizes the magnet should be ground/common.
@@jebadiaha Thanks a ton for this response.
Anyone know how to check relay #2?
good stuff friend!
Excellent video, but you should have shown it working after being fixed.
How can a microwave need so many relays?
very nice
Very nice video
Nice video