Vacuum cleaner repair - Page 1
Forum section: electronics / repair

author: Its wednesday my dudes
author_rank: Contributor
timestamp: March 12, 2021, 10:36:21 am
content: Hi guysYesterday I discovered that my vacuum cleaner suddenly stopped working. But before throwing it out and replacing it with a new one I want to give it a repair attempt. Since I am dealing with mains voltage here and my usual projects is simple low voltage hobbyist stuff I wanted to get some input first.Basically the vacuum cleaner gives no sign of life when turning it on. Cables are good. I opened it up and this is the board. So far I googled, that it consists a triac (package code something likeBTB12 6008 DT(?), couldn't find the exact match). The other IC (package codeCR8F6 1D12(), didn't find anything about it) might be a microcontroller. The board has a NTC thermistor connected to it. So would your plan of attack be? I was thinking about unsoldering the triac and testing it if it works according to this manual.https://instrumentationtools.com/test-triac-multimeter/I was also thinking about a quick and dirty fix by bridging the triac contacts so that the motor just runs on full power all the time. Not sure if this is a good idea though, since there is a NTC present.I've attached some pictures of the board.Thanks!

author: perieanuo
author_rank: Frequent Contributor
timestamp: March 12, 2021, 11:09:23 am
content: verify voltage on big electrolytic cap, with care, you have 220V on that pcb, maybe the blue thing is the fuse is it ok?maybe you got lucky and some condensator is dead, like the yellow one who i guess make the small voltage for the IC with the rectifier diode next to him (D1?)verify the zener also, maybe it's deadthe board should be easy to fix unless the IC is dead

author: amyk
author_rank: Super Contributor
timestamp: March 12, 2021, 02:36:35 pm
content: How "smart" is this vacuum to need a microcontroller...?You can test the motor by bypassing the triac. I assume this is not a cordless one and the motor is a universal brushed motor.The MCU looks like it's powered by a capacitive dropper so check the capacitance of C1 - they tend to fail by decreasing in capacitance over time.If you don't need the "smart" extra features you can always get a suitably rated switch and turn it into a regular dumb vacuum.

author: wraper
author_rank: Unknown
timestamp: March 12, 2021, 02:39:10 pm
content: First check if motor has continuity to begin with. It may be just worn off brushes.

author: EHT
author_rank: Frequent Contributor
timestamp: March 12, 2021, 10:15:22 pm
content: It looks similar to thisMieleI fixed.Quote from: amyk on March 12, 2021, 02:36:35 pmOh yes! I was surprised by this too - same in the Miele!Quote from: amyk on March 12, 2021, 02:36:35 pmYes, that is what failed in mine. Measure DCV and ACV on the microcontroller's power lines. The thing which was most fiddle was finding a replacement that would physically match.Also you can test the triac by using a bench PSU to apply a few volts to the gate and a small load like an LED. Test it in both directions. This was easy on the Miele because the triac was mounted externally.

author: wraper
author_rank: Unknown
timestamp: March 12, 2021, 11:06:55 pm
content: I doubt that this is microcontroller. More like analog phase shift control IC for power regulation and overheat protection.

author: amyk
author_rank: Super Contributor
timestamp: March 13, 2021, 12:42:16 am
content: Quote from: wraper on March 12, 2021, 11:06:55 pmI suspect it is one of the "CR8F" family, possibly CR8F6122:https://datasheetspdf.com/pdf-file/1054727/STMicroelectronics/CR8F6122/1...of which there is disturbingly little information out there, just these datasheets, andzeromention of that product or even the "CR8F core" on ST's own website.

author: wraper
author_rank: Unknown
timestamp: March 13, 2021, 01:50:48 am
content: Quote from: amyk on March 13, 2021, 12:42:16 amPinout seems to match.

author: Its wednesday my dudes
author_rank: Contributor
timestamp: March 14, 2021, 09:33:04 am
content: Hi guys,Thanks for your help. I worked through the list of your suggestions and turns out that the big capacitor was dead. Swapped out the capacitor, now the cleaner works flawlessly again. Thanks alot!

author: Raj54
author_rank: Newbie
timestamp: December 05, 2023, 07:08:42 am
content: Please be careful when checking the voltage on the large electrolytic capacitor. The PCB may have 220V, so exercise caution. The blue component may be the fuse - please check if it's okay. It's possible that a capacitor, such as the yellow one that provides low voltage to the IC with the rectifier diode (D1), is dead. Please also check the zener - it may be dead as well. Fixing the board should be easy unless the IC is dead.

author: cruff
author_rank: Regular Contributor
timestamp: December 07, 2023, 01:59:20 pm
content: The original poster reported that it was repaired more than two years ago.