This same scenario occurred with our microwave (capsule released from the screw base while removing it with the light circuit energized). The base shorted, but the end result is the HL won't light at all with an incandescent lamp. When an LED version of the bulb is installed it illuminates partially all the time but with an incandescent it does nothing. I assume there is some quirky failure mode of the triac. The PCA is a W10800189. Would you be able to identify which is part is the triac in question? Could it be one of the two TO-220 package parts I see? Thanks in advance.
Wow, just like you said, the same happened to my smart ass. I went to take off the bulb, was like "nah, I shouldn't need to power it off". Next second I see the bulb had already broken and by the time I went to turn it to remove it, the 2 wires touched... And you know the rest. My triac was also bad, and then I found your video haha. Thanks again!
I'm curious: what design change could have protected these triacs when the bulb blows and shorts? Could an extra inductor/choke inline with the light accomplish this?
@@TheTechCircuit love the idea of a switch on the access cover for the bulb. Smart. But, what about an inline fuse? I notice that you call out the 20a Line Fuse as "slow-blow". I'd assume, then, that there are fuses which respond quicker to overcurrent. Is this a thing? Perhaps more complex, but could the board also potentially sense current and disable voltage to the triac after so many 0a readings? In other words, if the board sensed 0 amps after so many checks, voltage supply to the load would be removed.
@@garrybaker7656 Yes there are more quickly reacting fuses, but since there is still a delay, the current spike may dstill take out the semiconductor junction. About monitoring the current - certainly there are ways to do that and to disable the triac - and while the engineers are at it, throw an error message prompting a bulb change.
This all makes sense, kind of. That said, do I really need to replace the entire board, or is there a fix for this? Or am I just going to have to do without that light? Personally, I do not care, but my wife is irritated that the light feature doesn't work.
The main things I look at are Vdrm (peak off-state voltage), and It-rms (RMS on-state current). The BT136-600E is what I use as an exact replacement for the WP MW. It has a Vdrm of 600v (remember that 120v rms is 172 peak - so 600v gives plenty of head-room). It-rms is just the load current the triac can sustain. The BT136-600E can handle 4A, which is plenty for its application. I also keep the BT136S-600 in stock as it is the surface mount version of the above. Both of the above triacs are (sensitive gate) types, which allows for easy driving of them by common opto-triacs that isolate and are driven by microcontrollers as covered in the video. Although the BT136 will replace lots of common triacs, if at all possible, I try to replace triacs with the exact part number.
I replaced the Triac. Now my LED bulb flickers at off. Then I noticed it says non-dimmable. Ordered a dimmable one from the jungle site. Hope this fixes it so I don’t have to buy a $110 board.
Sometimes removing the bulb causes the wires in the socket to cross and short out the light circuit. Unfortunately most people don't unplug the microwave before they do this and don't realize that the light circuit is actually activated at that time.
@@TheTechCircuit This is the first bulb that's blown since new in 2019. Tried new bulb, then another...then went googling for an answer...apparently this is common place. No warning labels anywhere near the bulb to explain to unplug appliance. I'm sure it's covered in the 12 pages of warnings and cautions in the manual, if only I knew where the wife placed that....🤣
