scorpio_stg
Newbie level 3
pcb trouble shouting tips
Hi Everyone,
I hope someone here may be able to help me.
I have an offline UPS made by a local manufacturer who has since closed his business.
The circuit uses a SG3524N PWM controller, three AS324P quad op-amps, a MOC3021 opto-coupler and six P55NF06 MOSFETs to give a 220vac/50Hz (600 VA) output from a 12vdc/31AH lead-acid car battery.
I am attaching two photos of the inside of the UPS here. One is with the transformer and the pcb in low res and the other one is higher res of just the main pcb. The reson for the photos is that I am hoping someone here may be able to recognize the circuit and help me out with the trouble-shooting.
The problem is that the UPS is not switching fast enough to keep my desktop computer on during a heavy fluctuation or a power outage. The computer restarts making the UPS really useless. The load is just a single computer with a 17" CRT display - it should not be more than 350 watts total.
The battery is fairly new as it is still under warranty but I don't think that it is the guilty party here because once the computer reboots through the battery, I have used it for more than half an hour and there was no indication that the battery was running out.
Any helpful advice about tweaking or trouble-shooting this circuit would be deeply appreciated since I don't really have the budget for a new UPS. I do have a DMM but no oscilliscope so wave analysis is not possible.
So if someone recognizes this circuit, please let me know. If someone has a schematic for this, I can try to trace the circuit myself and see if I can fix the problem.
Thanks in advance for any help.
Hi Everyone,
I hope someone here may be able to help me.
I have an offline UPS made by a local manufacturer who has since closed his business.
The circuit uses a SG3524N PWM controller, three AS324P quad op-amps, a MOC3021 opto-coupler and six P55NF06 MOSFETs to give a 220vac/50Hz (600 VA) output from a 12vdc/31AH lead-acid car battery.
I am attaching two photos of the inside of the UPS here. One is with the transformer and the pcb in low res and the other one is higher res of just the main pcb. The reson for the photos is that I am hoping someone here may be able to recognize the circuit and help me out with the trouble-shooting.
The problem is that the UPS is not switching fast enough to keep my desktop computer on during a heavy fluctuation or a power outage. The computer restarts making the UPS really useless. The load is just a single computer with a 17" CRT display - it should not be more than 350 watts total.
The battery is fairly new as it is still under warranty but I don't think that it is the guilty party here because once the computer reboots through the battery, I have used it for more than half an hour and there was no indication that the battery was running out.
Any helpful advice about tweaking or trouble-shooting this circuit would be deeply appreciated since I don't really have the budget for a new UPS. I do have a DMM but no oscilliscope so wave analysis is not possible.
So if someone recognizes this circuit, please let me know. If someone has a schematic for this, I can try to trace the circuit myself and see if I can fix the problem.
Thanks in advance for any help.