Hi:
I am trying to repair this modular ATX PSU. It only has the 5V Standby and PSON enabled (3.33V).
PSON is delivered by (ST9S429-PG14) in pin4. This chip is a Voltage controller but it doesn't seem to trigger any PWM signal to pass it to primary through coils and "move" the big mosfets. Also next to it there is a EST7618 that it also seems a voltage controller.
Not sure if in the right direction, but trying to find where PWM signal is generated.
Green section seems that could be the "PWM section". It's driven by a CM6901 (back side).
So far:
- I've checked the 3 opto couplers. They seem ok
- I've checked the 5 pieces (igbt, shotky......) from the khaki section and they read ok.
Any recommendation where to focus the analysis?
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I am trying to repair this modular ATX PSU. It only has the 5V Standby and PSON enabled (3.33V).
PSON is delivered by (ST9S429-PG14) in pin4. This chip is a Voltage controller but it doesn't seem to trigger any PWM signal to pass it to primary through coils and "move" the big mosfets. Also next to it there is a EST7618 that it also seems a voltage controller.
Not sure if in the right direction, but trying to find where PWM signal is generated.
Green section seems that could be the "PWM section". It's driven by a CM6901 (back side).
So far:
- I've checked the 3 opto couplers. They seem ok
- I've checked the 5 pieces (igbt, shotky......) from the khaki section and they read ok.
Any recommendation where to focus the analysis?
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