Hi,

Recently i got an Powercom UPS from local scrapyard with unknown condition. Before powering it i removed case and inspected UPS for faults. I figured out that lead acid batteries are long gone but main PCB and transformer was looking fine.

My UPS seems an ancient model that i couldn't find any info about it so i looked archive.org for it.

Here is archive.org web page snapshot:

https://web.archive.org/web/20010419163838/ht … ar/standby.html

After powering it with 24v externally with adjustable power supplies it seemed working (outputs 220v) but when i load its output (small 10w load or 100w load it does't matter) it shuts itself down. I tried with multiple loads such as laptop charger, light bulb, soldering station the result is always same. After switching UPS main switch it seems working again but when i try to load it it again shuts down.

So i started to troubleshoot PCB.It has 2 main chips marked as below:

C34102AE
V23
9539
INTEL 1980

B9452XX
ADC0809CCN

Top one (i assume its a microcontroller) has no information on web as i know. Bottom one is analog to digital converter.

I measured MOSFET gates with scope it seemed fine.Also measured output also it seemed fine.

There are no schematics for UPS for troubleshooting. Does anyone have any advice?