Did you measure the resistance of the FETs with the gate disconnected from the circuit? (from post 15)
If so, what were the individual readings.
If so, what were the individual readings.
sure, not much change from post 14
i allready have all four new one, readings varies so much from new ones im changing them.
on rectifer second diode is 2way, need new one
on pwm 9 and 10 are different, need new one?
i allready have all four new one, readings varies so much from new ones im changing them.
on rectifer second diode is 2way, need new one
on pwm 9 and 10 are different, need new one?
If you're not going to give me what I ask for (precisely), someone else will have to help. I can't read minds.
And the voltage on pins 9 and 10?
Are all 8 FETs now new and installed?
And all gate resistors now in the circuit?
Are all 8 FETs now new and installed?
And all gate resistors now in the circuit?
i dont have new rectifier, outputs are still old, dont remember their readings
Pin 9: 5.48v
Pin 10: 8.72v
this was it when three powers supply fets and broken rectifer were on board
havent measure since
Pin 9: 5.48v
Pin 10: 8.72v
this was it when three powers supply fets and broken rectifer were on board
havent measure since
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Perry, may i power up without power supply fets and that rectifier to measure 9 and 10 again?
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Gonna put new irz44´s. As you see old are ohm range and new are Mohm range
Am i point after changing that rectifier to measure something or just putting fets too and hope for best?
power supply gate resistors are 88 87 88 90, sure could change them too. output sector seems to be ok
i believe it could be best to turn it on with weaker power supply rather than straight battery power, i do have power meter and i can switch it off maybe fast enough
Am i point after changing that rectifier to measure something or just putting fets too and hope for best?
power supply gate resistors are 88 87 88 90, sure could change them too. output sector seems to be ok
i believe it could be best to turn it on with weaker power supply rather than straight battery power, i do have power meter and i can switch it off maybe fast enough
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You will generally use a low rated fuse (10 amp) or a current limiter when initially powering the amp up. Clamping the heatsink mounted components offers even greater protection.
The gate resistors need to be 91 ohms ±5%.
Leave the rectifiers out for now. When you power it up, if there is no excessive current draw, confirm that all FETs read about the same as pins 9/10. Black on source leg. Red on gate leg.
The gate resistors need to be 91 ohms ±5%.
Leave the rectifiers out for now. When you power it up, if there is no excessive current draw, confirm that all FETs read about the same as pins 9/10. Black on source leg. Red on gate leg.
yea i believe that rectifier is quite vital component, gonna hook off that second one too.
at least now there is same 4.35v on all four fets leg
thanks
at least now there is same 4.35v on all four fets leg
thanks
Did you check all of the output transistors to see if any are shorted?
I don't understand the statement about the rectifier.
I don't understand the statement about the rectifier.
Between gate and source 189-190ohm all four. Output sector seems to be ok. Draws 3.4w without rectifiers on board
Is there any evidence of electrolyte leakage (darkening of the board or an oily substance) around the primary filter caps?
If the output stage appears to be OK, you can install the rectifiers, clamp everything down tightly and power it up through a low-rated fuse or a current limiter.
If the output stage appears to be OK, you can install the rectifiers, clamp everything down tightly and power it up through a low-rated fuse or a current limiter.
what do you think, was it rectifier which took fets or other way around.
caps visible ok, did not measure them
caps visible ok, did not measure them
Don't reinstall a shorted rectifier if one was shorted.
The FETs can't harm the rectifier. If a rectifier or output transistor failed (shorted), those can damage the FETs. A shorted transformer or even random failure of one of the FETs can cause the FETs to fail.
The FETs can't harm the rectifier. If a rectifier or output transistor failed (shorted), those can damage the FETs. A shorted transformer or even random failure of one of the FETs can cause the FETs to fail.
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