I've got a faulty Sony APS-06 PSU which had leaky caps all over. I've replaced all the caps including the SMD's on the daughter board.
When shorting pins 9-10 the relay clicks on and then almost instantly clicks off. (I'm trying to get the PSU working separately before connecting it back to the motherboard)
I'm looking through the schematic trying to figure out where the problem issue but the circuit is scrambling my brain.
First off are there any electronic gurus out there that can explain the circuit basics.
From what I can gather mains is rectified and then goes through a simple SMPS circuit to generate 12V (For the PWM IC on the daughterboard) and 5V for the trickle via a zener diode.
The M51977 PWM IC on the daughterboard then does some magic to generate a PWM signal and has some circuitry to disable itself on overvoltage, or over current.
The PWM is then used to generate +-12 and +5 which is fed back to the PWM chip. Once we have 12V it turns on the relay which connects the accessory plug.
I'm getting a stable 5V on the trickle so guessing the top half of the circuit is working fine (mains to 12V/5V). When I power on, I get 5V on the output and then the PWM IC is presumably shutting down which then turns the 5V/12V/Relay off.
So my issue could be something on the daughterboard, or too much current being drawn which causes the IC to shut down)
I've scoured the net looking for someone who has done a in-depth repair of this PSU and can provide voltages on test points, or even better oscilloscope references but no luck.
I'm now trying to work out if I can remove the daughterboard and power separately to at least see if thats working properly but will need to supply it with -+12 and +5
Yes, I know I could just replace this with a ATX power supply, but I would like to fix this up and hopefully learn a few things along the way.
Any pointers, or help from anyone who has repaired one of these.
When shorting pins 9-10 the relay clicks on and then almost instantly clicks off. (I'm trying to get the PSU working separately before connecting it back to the motherboard)
I'm looking through the schematic trying to figure out where the problem issue but the circuit is scrambling my brain.
First off are there any electronic gurus out there that can explain the circuit basics.
From what I can gather mains is rectified and then goes through a simple SMPS circuit to generate 12V (For the PWM IC on the daughterboard) and 5V for the trickle via a zener diode.
The M51977 PWM IC on the daughterboard then does some magic to generate a PWM signal and has some circuitry to disable itself on overvoltage, or over current.
The PWM is then used to generate +-12 and +5 which is fed back to the PWM chip. Once we have 12V it turns on the relay which connects the accessory plug.
I'm getting a stable 5V on the trickle so guessing the top half of the circuit is working fine (mains to 12V/5V). When I power on, I get 5V on the output and then the PWM IC is presumably shutting down which then turns the 5V/12V/Relay off.
So my issue could be something on the daughterboard, or too much current being drawn which causes the IC to shut down)
I've scoured the net looking for someone who has done a in-depth repair of this PSU and can provide voltages on test points, or even better oscilloscope references but no luck.
I'm now trying to work out if I can remove the daughterboard and power separately to at least see if thats working properly but will need to supply it with -+12 and +5
Yes, I know I could just replace this with a ATX power supply, but I would like to fix this up and hopefully learn a few things along the way.
Any pointers, or help from anyone who has repaired one of these.
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