I recently got those two UPSes. The Victron Pico 102 is a mid-80s/early 90s 200VA backup-ups i.e. it switches the load with a relay to the inverter when primary power fails. The Micro 104 is a 400VA online-ups, that is it generates the output AC from an internal DC bus that is jointly supplied by the battery and line voltage. So it doesn’t have a switchover period, at the compromise of a higher-standby usage and inverter reliability.
The intermediate DC bus capacitors can kill you.
This post is not a repair instruction, it is here just to show and document what I did to get those units back to shape.
Victron Pico 102
The Pico 102 I got was in overall good shape, but there was a cooked resistor and some of the capacitors are right next to heatsinks that quite hot during operation.
The front-panel wasn’t holding so I put it back on with some double sided tape:
Of course they used RIFA capacitors and of course they were cracked and just waiting to catch fire. I removed them and replaced them with new Y class capacitors.
Next I replaced the cooked Vitrohm 15k/7W resistor with a new one, I left slightly more lead spacing than the old one.
Running on battery here powering a PAR30 stage light with a 75W halogen bulb
The plastic thingy-things they used to lock the unit were fairly broken, so I just epoxied some M4 bolts onto the inside of the case with automotive rated 2K epoxy. With this I can close the unit with M4 screws and washers instead, which I find way more convenient and reliable. I also put on glue-on rubber feet since the unit was just standing on the plastic screw thingies before.
After that I put a new battery in it and tested it for a day, worked flawlessly. Not sure what I’m going to use this for yet.
Victron Micro 104
The Micro 104 was fairly dirty but otherwise worked. I immediately spotted something RIFA looking on the circuit board and low and behold its also a RIFA and its also cracked - surprise. I replaced it with a new Y class 4n7 capacitor.
I then used rust primer to take care of some rust spots inside the case and applied white paint again to mask it.
The whole heatsink assembly was quite dirty, so I disassembled everything and cleaned the heatsink pieces in my ultrasonic cleaner. The heatsink pieces were riveted in, so I drilled the rivots out and instead assembled it back together with screws. I also applied new thermal compound and replaced a couple dodgy capacitors on the board.
I then finally replaced the fan and added an aluminum filter as well to stop coarse dirt to get in.
