Make sure the high voltage capacitor is discharged before touching terminals

@steve83803

4 ай бұрын

Agreed, “The 3 Ds” Disconnect from mains supply, Door open for interlock isolation, Discharge HV capacitor. Never had a capacitor crack over when shorted but the one you don’t do may be the one that kills you!

@anthonyg4671

4 ай бұрын

sucking eggs comes to mind.🤔

@michaeldranfield7140

4 ай бұрын

of course, don't just rely on the internal 10Meg resistor inside the high voltage capacitor , I have had these go open circuit many times .

@michaeldranfield7140

4 ай бұрын

@@steve83803 on a microwave training course we were told to disconnect the mains plug and place it inside the oven, this ensures the door stays open and no one else can accidentally plug it into the mains .

@steve83803

4 ай бұрын

Seem to remember it was Sharp with the 3Ds we started repairing Microwave ovens at Masterscare and all had to complete the course.

When I worked at Mastercare they had a “customer education” charge of £30.00 if the call out was something stupid like flat batteries in the remote or the appliance was unplugged, we called it the “Idiot charge” I had a call to a digital microwave for a timer fault, it was in a very posh area with an equally posh customer. “There’s something wrong with the display countdown, look ( demo by customer ) I set it to 1.30 ( one minute and thirty seconds) and when it gets to 1.00 ( 1 minute) it suddenly jumps to 59 instead of 99.” After a brief explanation of how many seconds are in a minute I left along with £30.00.

Mine did exactly this I just tightened all the crimps up and 15 years later still working.

What a strange outcome I would of thought the loose one would of been burnt lol thanks Michael 😊

@michaeldranfield7140

4 ай бұрын

you would have thought so .

Great video Michael. Thanks for taking the time to do this

@michaeldranfield7140

4 ай бұрын

Many thanks for that .

Used to be a problem on the pre inverter Panasonics, the wire would work loose in the crimped terminal and cause intermittent operation. Rightly or wrongly, I used to flow a bit of solder into the crimp. Never had any come back failed again.

@michaeldranfield7140

4 ай бұрын

like the one the service manual is for ! I did the same on this solder the connection after crimping , I'm not a big fan of just relying on the crimp.

@TurboTel68

4 ай бұрын

@@michaeldranfield7140 yes, very similar. I was working for BSH home appliances so they were essentially the same Panasonic units with a build-in kit strapped to them

Another great video Michael, thanks for taking the time to put this up. 😄

@michaeldranfield7140

3 ай бұрын

Many thanks for watching .

The 'TIGHT ' one Arc welded it onto the Terminal but causing a DRY CONTACT in the process thus couldn't gdt full POWER through.

@michaeldranfield7140

4 ай бұрын

but you would have thought the loose connection would be burnt also

Thank you Mr. Michael, this is a great informative video. I appreciate it.

@michaeldranfield7140

4 ай бұрын

Many thanks for that .

@truthreigns7

4 ай бұрын

@@michaeldranfield7140 you are most welcome

Cannot believe he never mentioned how dangerous it is to play around with a magnetron and associated capacitor. Can be lethal.

great info, thanks

@michaeldranfield7140

4 ай бұрын

Many thanks for watching .

Thanks for sharing 👍

@michaeldranfield7140

3 ай бұрын

No problem , many thanks for watching .

🤔 cheers, if you’re not sure leave well alone, these things can kill

@michaeldranfield7140

4 ай бұрын

Of course , a microwave is a dangerous item , in fact when I first started repairing microwaves back in the early 90s no one would supply with spare parts until you had passed a recognised microwave training course but these days anybody can buy spare parts on the internet regardless of what qualifications you have or don't have .

These spade terminals don't seem to perform well in high current applications. I've seen the same problem so many times in Computer UPS supplies where they fail in low voltage/ high current battery connections.

@michaeldranfield7140

4 ай бұрын

Couldn't agree more , they are a disaster in catering equipment such as hotplates and deep fat fryers.

Another interesting video - thank you for sharing it with us. Surely such an important connection should be made with something better than a "push on" connector? Why couldn't they have used a "bolt on" type connector that made a perfect connection 100% of the time?

@michaeldranfield7140

4 ай бұрын

Some industrial magnetrons do have bolt on terminals but not in the domestic world .

@opapagaio15

2 ай бұрын

Because then they wouldn't fail at warranty + a day & the makers wouldn't sell as many new microwave ovens.

@michaeldranfield7140

2 ай бұрын

@@opapagaio15 of course, and the makers need to keep selling new ones as there not making the money they use to , I remember selling 0.8 cu ft microwaves back in the late 80 s at £99 , now 40 years later a same size oven can be bought for £40.

weird how the loose connection had no burning but the tight one did, i would have thought it would be the other way round

Would a soldered joint not be better, or could that damage the magnetron internally?

@toolsarecool

4 ай бұрын

I think you don’t see these soldered because of heat and the low melting point of solder. Same in toaster ovens, coffee makers, etc. Spot welding may help, but that makes servicing a bit harder.

@michaeldranfield7140

4 ай бұрын

I dont think you would damage the feedthrough capacitor by soldering but it would have repairing harder in the future .

Make sure to discharge the Capacitor before doing anything inside a Microwave.

@michaeldranfield7140

4 ай бұрын

Absolutely , don't rely on the internal 10 meg resistor inside the capacitor , I have had these go open circuit many times .

Thank you very much for this tip!!! However i am somewhat surprised that the filament current is so damn high. Do you have an idea what is the reason why they run the microwave filament that high on current and let's say simple valves are relatively low on current ?

@kikopasinecki5110

4 ай бұрын

The power of the magnetron is about 800W and the tubes are about 30,40W.And there are thermal loses in the magnetron that draw current.

@michaeldranfield7140

4 ай бұрын

Its a very high power device with a relatively low efficiency , some transmitting tubes run at a ridiculous heater current, the 4CX10,000D needs 7.5 volts at 78 amps !

Whenever I repair a microwave I cut off the quick-disconnect terminals and solder the wires to the connections. Mostly on the door switches.

Every microwave I've repaired has been 9 out of 10 times the diode.

I can understand why the manufacturer uses plugs for the heater wires but for a repair wouldnt a soldered connection be the best route? (and save the cost of replacement connectors....)

@michaeldranfield7140

3 ай бұрын

Soldered connection would be better but it makes fault finding and parts replacement more difficult .

Probably wrong but id it possible the connector that welded on eas carrying more current than rated cause of the other connection being loose. Great video thanks.

Note it is Very Dangerous to open a Microwave if the main Capacitor is charged up it can have 2500 Volts on it when on load and 5000 Volts off load sometimes if a fault occurs. THIS HI VOLTAGE WILL KILL YOU. SO IMPORTANT TO DISCHARGE THE CAPACITOR SAFELY FIRST WITH A WELL INSULATED LEAD CONNECTED TO EARTH FIRST . Best left for Experiencend Engineers to Service

Number of repaired ovens I see where the FA and F are wrong way round.

yes, you can see it is loose.

@michaeldranfield7140

4 ай бұрын

But the loose one is not the burnt one !

very common fault some people leave it a bit late with soghns of burning

@michaeldranfield7140

4 ай бұрын

I have seen the odd one that's so burnt the magnetron has had to be replaced .

The ONLY reason the top one was not loose also , was that the corrosion and carbon was "welding " it tight.

@michaeldranfield7140

4 ай бұрын

of course but you would have expected the other to burn also .

@michaeldranfield7140

4 ай бұрын

Maybe .@@peacebeuntoyou8934

@jimw7916

4 ай бұрын

@@michaeldranfield7140 well... No cos the very FIRST one to start burning would then be the ONLY one with "resistance" causing ALL the voltage to be dropped across it. The other connector would then become the "better" connection. Also the carbonized one would continue to get worse due to more resistance across it thereby producing more carbon.

Thanks! Contact problems are a very common reason for all sorts of failures. I would also add oil (universal lubricant spray) to the cleaned contacts to prevent oxidation.

Don’t you think a prominent safety warning would be appropriate at the beginning?

@michaeldranfield7140

3 ай бұрын

no safety warning comes with spare parts when customers just buy them off the internet , when I first started doing microwaves no one would supply you with spare parts unless you had passed a recognised microwave safety course, now anybody can buy any part from the internet regardless of what they know or dont .

Unqualified people should not try to repair microwaves..They could end up dead. This video needs to be removed.

@mauanderuk

4 ай бұрын

Killjoy

@chrismurphy7324

4 ай бұрын

the high voltage will discharge automatically when not plugged in , any residual voltage will not kill you

@daviddillon172

4 ай бұрын

Not true. If there is a fault on the components it may not discharge. The 3 D's...Disconnect..Door open...Discharge..