i have being working on this invert 500watt
i fine out that there is no 12v on tl494 number 8 pin and the input mosft gate are all 12v
if are add mosft to it, it we blow offm what will be the problem

 

The TL-494 can not supply enough FET-Gate-Drive-Current for a very High-Power-MOSFET.

2 separate, dedicated, Gate-Driver-Chips will be required to get good Switching-Performance and
to avoid burning-up your expensive High-Power-FETs.
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but th

The TL-494 can not supply enough FET-Gate-Drive-Current for a very High-Power-MOSFET.

2 separate, dedicated, Gate-Driver-Chips will be required to get good Switching-Performance and
to avoid burning-up your expensive High-Power-FETs.
.
.
.
View attachment 327517
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but the dc side of the input mosft gate side is giving 12v when murs with meter, most that be the cost of transisors

 

The Gate of a MOSFET acts exactly like a Capacitor.
This Capacitor will have to be Charged-Up, and then Discharged, at an extremely high Frequency.
This may require a serious amount of Current, not just "Voltage".

Hopefully, your design, ( which we haven't seen yet ), does not use excessively high Frequencies.
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This is the inverter pic

The Gate of a MOSFET acts exactly like a Capacitor.
This Capacitor will have to be Charged-Up, and then Discharged, at an extremely high Frequency.
This may require a serious amount of Current, not just "Voltage".

Hopefully, your design, ( which we haven't seen yet ), does not use excessively high Frequencies.
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This is the pic of the inverter, all the gate , source and the emiti are all given out 12v which I have not com across this kind of issue before we

 

No Picture .............
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No Picture .............
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sorry for that this is the oic

 

You didn't say that You were trying to repair a commercially produced inverter.
That's a whole different bucket of Worms.

Good Luck.
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