libyantiger
Member level 5
i am in electronics repair in inverter repair since very long time
never ever i have seen some thing like this before it is just like a big mystery to me
if u dont know inverter then i will give brief introduction on what going on and use it as prelude to own questions
it is process of simply cutting dc across step up transformer using mosfet and power ic and produce high dc around 300vdc
and cut this dc again to create sort of square wave the resembles ac
the mosfet configuration is usually push pull but the transistors are them selfs connected to ground
here the transistors are not connected to ground they just go to other transistors and then these transistor are connected to ground
it should been done using a and b transistors ( see picture to know a transistor and b transistor)
why the bottom transistors? why? i just called them (ground bringers) cause they sort of "introduce ground when they turned on"
to add insult to injury the control board right now have no ground u followed its track of ground to find it dead end at the connection of upper
transistors to the lower transistors or ground bringers
in my life i opend 100 or 1000 of them and i used my golden trick to repair them ....remove bad fets ....look for good nice square wave at the gates
if it is not there or it is sort of distorted square wave then find bad reistors drive transistors or ic tl494 or sg3525 as those the most used ics in inverter.
till this inverter come in and hit my face and turned down of plans ...simply when i removed all fet and powered it on it never show a sign of it working
and when i follow the power to the small controll module board i find that vcc is ok but ground is dead end as shown in the picture
any ideas ?
brief is why the wierd connnection of fets
and why the board have no ground it is just floating in air with no ground that is just unacceptable able
never ever i have seen some thing like this before it is just like a big mystery to me
if u dont know inverter then i will give brief introduction on what going on and use it as prelude to own questions
it is process of simply cutting dc across step up transformer using mosfet and power ic and produce high dc around 300vdc
and cut this dc again to create sort of square wave the resembles ac
the mosfet configuration is usually push pull but the transistors are them selfs connected to ground
here the transistors are not connected to ground they just go to other transistors and then these transistor are connected to ground
it should been done using a and b transistors ( see picture to know a transistor and b transistor)
why the bottom transistors? why? i just called them (ground bringers) cause they sort of "introduce ground when they turned on"
to add insult to injury the control board right now have no ground u followed its track of ground to find it dead end at the connection of upper
transistors to the lower transistors or ground bringers
in my life i opend 100 or 1000 of them and i used my golden trick to repair them ....remove bad fets ....look for good nice square wave at the gates
if it is not there or it is sort of distorted square wave then find bad reistors drive transistors or ic tl494 or sg3525 as those the most used ics in inverter.
till this inverter come in and hit my face and turned down of plans ...simply when i removed all fet and powered it on it never show a sign of it working
and when i follow the power to the small controll module board i find that vcc is ok but ground is dead end as shown in the picture
any ideas ?
brief is why the wierd connnection of fets
and why the board have no ground it is just floating in air with no ground that is just unacceptable able
