Dear forum members,
I came here for some help with repairing this PSU.
I have attached every pdf I could find for it. I even contacted ABB (this company bought Power-one back then) and asked for schematics, but they didn't even answer.
This nice PSU came to me with short on the mains filter capacitors (2 of them were leaking the electrolyte, and caused a short) and it even blew the inrush current limiters. I attach a few photos, so far I have done the following:
-desoldered all main capacitors, cleaned the mess and digged down to the inner layers to see, if there is an other blown copper trace inside (luckily did not find any)
-soldered in 1 main cap. per side for test (the 7pcs on each side is connected parallel)
-soldered 2 NTC inrush current limiters in (for test)
-soldered the 2 PFC coils on the opposite side of PCB, so I have more place to measure (this PSU is really crowded)
-As doing this, I measured the coils with an ohmmeter, they both showed 0.32 ohm, I hope this means they both are good.
-The switching FETs are not shorted, they all measure good in-circuit.
-The PFC driver ICs seem a bit off. I assume they should measure identical values, as the whole build-up seems symmetrical. The one on the upper side has 3.5V on PIN3 (over-voltage protection), the lower side one has 1.5V on the same PIN. I was looking at the application circuit in the datasheet of the named IC (L4981A), and it showed that this voltage should come from a voltage divider inbetween +400V and GND. The same applies for PIN14 (voltage error amplifier), the lower side gives different reading than the upper side. Yet, they all measure the same ohmic values to GND and to +400V when turned off.
You also can see a TOP224GN, it is the standby circuit, and it works fine. It gives 12V, and it gets to both PIC microcontrollers. I can even communicate with the PSU via I2C, but I can only read. Tried to clear the fault bits in byte 128 and 129, with no success. On the backplate there are pins arranged in 4x5. I shorted the corresponding pins to start the PSU (R1 to logic GND) but it does nothing. Now when I apply mains power to the circuit, the front yellow led turns on, but nothing else. It can mean 2 things, according to the operator's manual: input AC low/missing or PSU failed.
The rectified mains are present on the main buffer capacitors (310V), but the PFC won't turn on.
Now I am stuck here, have no ideas. Feel free to chime in. Maybe someone out there has a schematic for it, that would be awesome.
I came here for some help with repairing this PSU.
I have attached every pdf I could find for it. I even contacted ABB (this company bought Power-one back then) and asked for schematics, but they didn't even answer.
This nice PSU came to me with short on the mains filter capacitors (2 of them were leaking the electrolyte, and caused a short) and it even blew the inrush current limiters. I attach a few photos, so far I have done the following:
-desoldered all main capacitors, cleaned the mess and digged down to the inner layers to see, if there is an other blown copper trace inside (luckily did not find any)
-soldered in 1 main cap. per side for test (the 7pcs on each side is connected parallel)
-soldered 2 NTC inrush current limiters in (for test)
-soldered the 2 PFC coils on the opposite side of PCB, so I have more place to measure (this PSU is really crowded)
-As doing this, I measured the coils with an ohmmeter, they both showed 0.32 ohm, I hope this means they both are good.
-The switching FETs are not shorted, they all measure good in-circuit.
-The PFC driver ICs seem a bit off. I assume they should measure identical values, as the whole build-up seems symmetrical. The one on the upper side has 3.5V on PIN3 (over-voltage protection), the lower side one has 1.5V on the same PIN. I was looking at the application circuit in the datasheet of the named IC (L4981A), and it showed that this voltage should come from a voltage divider inbetween +400V and GND. The same applies for PIN14 (voltage error amplifier), the lower side gives different reading than the upper side. Yet, they all measure the same ohmic values to GND and to +400V when turned off.
You also can see a TOP224GN, it is the standby circuit, and it works fine. It gives 12V, and it gets to both PIC microcontrollers. I can even communicate with the PSU via I2C, but I can only read. Tried to clear the fault bits in byte 128 and 129, with no success. On the backplate there are pins arranged in 4x5. I shorted the corresponding pins to start the PSU (R1 to logic GND) but it does nothing. Now when I apply mains power to the circuit, the front yellow led turns on, but nothing else. It can mean 2 things, according to the operator's manual: input AC low/missing or PSU failed.
The rectified mains are present on the main buffer capacitors (310V), but the PFC won't turn on.
Now I am stuck here, have no ideas. Feel free to chime in. Maybe someone out there has a schematic for it, that would be awesome.
Attached Files
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