| General > General Technical Chat |
| Rovus cordless vacuum improving / unknown charger IC |
| (1/1) |
| Krotow:
Got Rovus BR-33B6 cordless vacuum as giveaway. Wanted to use it for casual computer cleaning. Then noticed that fully charged thing works only 15 seconds and then gradually fizzle out in next 20-30 seconds. Charging was painfully slow and happened only in switched off position. After few charging cycles decided to gut it out to see what is inside. Sorry, forgot about making "vanilla" photo and threw out battery before stumbled upon subject. AAA size 7.2V 1200 mAh NiMH "green" battery array, spot-welded together in series and tucked in gap around motor. Motor - most likely Chinese RS365. Drawed a circuit of this PCB in Kicad - had a reason to learn Kicad at last. See attached PDF. As expected - switching NiMH battery between charger and DC motor. I'm curious about which charging control IC Chinese "ingenious" mind used here. From function here it is more like a simple NE555 timer used to blink blue LED in 1 second interval. But pinout is different. Nothing to fix in vanilla state. Simply "improved" existing design by soldering out redundant components and connecting motor and switch directly to power connector on PCB. Only LED indicator remained to indicate working state. Test with lab PSU clearly stated that original battery was... erm... a little too weak for prolonged cleaning ;D So next task is to find suitable and handy enough PSU for this thing for cheap. Rovus_BR-33B6.pdf (30.46 kB - downloaded 239 times.) |
| amyk:
I don't see how that LED could light unless the IC had a negative voltage generator... Is there any marking on it? It could be what BigClive refers to as "anonymous 8-pin microcontroller". |
| Krotow:
--- Quote from: amyk on June 10, 2020, 12:15:40 am ---I don't see how that LED could light unless the IC had a negative voltage generator... --- End quote --- Ouch... my bad :-[ Yes, another reason to avoid drawing circuits at 2 AM. Update: Replaced PDF above to one with corrected LED position. --- Quote from: amyk on June 10, 2020, 12:15:40 am ---Is there any marking on it? It could be what BigClive refers to as "anonymous 8-pin microcontroller". --- End quote --- BigClive seems correct again. Can't see and touch anything on that IC nor wash away the top layer with isopropil/acetone. Look like IC came in preordered batch from manufacturer without any labeling on it. |
| Krotow:
An epilog to correctly finalize this thread. Turned out that battery fizzling out was simply a dead battery. Particular IC is some NiMH charger controller, probably custom made. However this all doesn't make sense anymore, because I have a new better vacuum now. And dumped the subject of this topic in electronic waste container. |
| Navigation |
| Message Index |