I need help identifying this ic marked c2 right side of the black caps. i think it a UCC27524 or a UCC2742 anyone know?
It seems to be a common issue with this board that the output fets blows and takes the irs20957s with it.
It seems to be a common issue with this board that the output fets blows and takes the irs20957s with it.
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forgot to upload the pic😳
i seem to have some trouble with one of the irs20957s, i have no ho o lo output on pin 14/10, pin 1 have 10v, pin 11 15v, pin 3 is a nice pwm signal, ive checked all pins between the two irs20957 and do not see any difference more than a scrambled ho signal on the working chip, traces for the gate drive are lifted on both ics.
both ics are replaced numerous times.
i seem to have some trouble with one of the irs20957s, i have no ho o lo output on pin 14/10, pin 1 have 10v, pin 11 15v, pin 3 is a nice pwm signal, ive checked all pins between the two irs20957 and do not see any difference more than a scrambled ho signal on the working chip, traces for the gate drive are lifted on both ics.
both ics are replaced numerous times.
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Might help if you had a better pic, and if you would sketch out a schematic of where the leads of that mystery IC go. If its a low cost board, it might only be two layers. If so, its pretty easy to trace out connections to help figure out the circuit function.
it was the bootstrap capacitor on ho which had come loose.
but while everything seem to work without rail voltage, the hi and low mosfets seem to short out with full rail voltage. without railvoltage this is what the gates look like.
but while everything seem to work without rail voltage, the hi and low mosfets seem to short out with full rail voltage. without railvoltage this is what the gates look like.
have finally made some progress, i changed both irs20957 and as soon as i did lo and ho disappeared on both 20957,
pin 1 10v
pin 3, nice pwm
pin 4 0v
pin 10 0v
pin 11 15v
pin 13 12v
pin 14 0v
pin 15 24v
referenced to pin 9
pin 2 was 0v which should be over 5v as i understand
lifted a 120k resistor (R155) which goes to pin 17 on mcu and then to a 150k resistor and a cap in parallel to ground
lifted a transistor (Q42) which connects to pin 20 on mcu
now i have voltage on csd and lo and ho works
what could be causing the mcu to shutdown the ics?
pin 1 10v
pin 3, nice pwm
pin 4 0v
pin 10 0v
pin 11 15v
pin 13 12v
pin 14 0v
pin 15 24v
referenced to pin 9
pin 2 was 0v which should be over 5v as i understand
lifted a 120k resistor (R155) which goes to pin 17 on mcu and then to a 150k resistor and a cap in parallel to ground
lifted a transistor (Q42) which connects to pin 20 on mcu
now i have voltage on csd and lo and ho works
what could be causing the mcu to shutdown the ics?
