![]() I hoped for the best and switched on the primary 230V AC voltage with a light bulb in series as protection against any short circuits on the power line that still might occur.īut the light bulb stayed completely off, and to my happy surprise the secondary connected 5V led light started to light up right away. (the resistor looks a bit burned but that was from another test, not this one!). ![]() The defect NPN transistor I already had replaced 2 weeks earlier and was a little bigger than its original was, Why I molded the plastic holder a bit using my hot air station to make some place for the higher replacement NPN, and for the defect emitter resistor I now just used a 3.9 Ohm 5% resistor to be able to test the charger circuit. And I immediately replaced the defect ‘67A’ pwm controller. Only just about 2 weeks later the 50 tiny sot 23-6 mlx02367A chips already arrived from the Chinese Aliexpress seller. This is important because else you would easily give the smd resistors completely wrong values! Next photo also shows the now also blown primary safety fuse resistor with code brown,black,black,gold (10 Ohm 5%), that was connected to one of both the ~AC pins of the diode bridge rectifier. All smd resistors are marked in the EIA-96 code for their values. And they needed replacements just as the NPN transistor just above R11. As we can see emitter resistors R11 and R10 placed in parallel are both open line now. In previous photo D6 is de greatz diode bridge rectifier, IC1 is the 67A smd component, and in the top right the Liteon optocoupler is present. Below is shown the solder side of this small charger board. The Lite-on 356T optocoupler was still good, so it was only the primary of the board where parts were destroyed. And on the secondary side of the 5V USB converter board all parts measured fine too. I measured both primary transformer coils with my Blue ring tester, and they looked fine. Not even its function! So I hoped that the ordered chip was the right one, and after I had replaced the old ‘67A’ chip I would soon find out if I was right. ![]() This IC from Melexis is a PWM controller but apparently because this mlx02367A is a special designed ASIC they were not allowed to give any datasheet or info on this chip and even the seller who sold me 50 of them couldn’t provide any information. ![]() ![]() And of course also the tiny sot23-6 controller with smd code ‘67A’ was no longer working. Not only the primary MJE13005 HV NPN transistor on the small 5V charger board was now completely short circuited, but also the 2 emitter resistors were gone, including the primary safety inrush resistor fuse to the greatz rectifier was blown. Replacing the old one was the best service he instantly could provide.Īfter I had removed the charger board from the brought over back flip box, I started examining its components. We got no clue what they did with the charger that made it completely blow up. My very handy nephew, who is a great professional new kitchen installer, brought over about a month ago an EVOLine 230VAC back flip Power outlet Box with now defect 5V USB charger board in it he had to replace at a customer’s house with a brand new EVOLine back flip box. ![]()
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