This Gateway FPD1965 is totally dead, no power light, doesn't twitch when the power button is pressed. All fuses are good, or at least the ones I found. The power resistor R904 measures 0.7 ohms. There is power coming in, 173VDC at the big capacitor.
That 173VDC is fed to pin 3 of the LD7552B PWM controller (IC901) through 3 series resistors (R909, R910, R931). It drops to 112 after the first resistor, 56 after the second, and is only 0.2V at pin 3 of the chip.
The Q903 FET has a resistance of no less than 9.5K between all pins.
Voltages on the digital board connector are all zero. Interestingly, whoever designed this chose to use the exact same connector type for power and keyboard input on the digital board. (No, I didn't attach them the wrong way, although maybe whoever had it before did.)
All electrolytics replaced with Panasonic FR and FC. None of the originals were visibly bad, or had bad ESR.
Should I replace the LD7552B? What US sources are there for replacements?
That 173VDC is fed to pin 3 of the LD7552B PWM controller (IC901) through 3 series resistors (R909, R910, R931). It drops to 112 after the first resistor, 56 after the second, and is only 0.2V at pin 3 of the chip.
The Q903 FET has a resistance of no less than 9.5K between all pins.
Voltages on the digital board connector are all zero. Interestingly, whoever designed this chose to use the exact same connector type for power and keyboard input on the digital board. (No, I didn't attach them the wrong way, although maybe whoever had it before did.)
All electrolytics replaced with Panasonic FR and FC. None of the originals were visibly bad, or had bad ESR.
Should I replace the LD7552B? What US sources are there for replacements?
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