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Trying to fix Black and Decker RT650 multitool

Discussion in 'Troubleshooting and Repair' started by gpatel_uk, Mar 4, 2012.

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  1. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    While using a borrowed multitool the unit went POP! when I turned it on. When I try to turn it on I can feel the power but no motor movement. I opened up the unit and bits of what looked like little bits of mirror fell out. The unit is not very complicated as its just a power cable connected to a circuit board (which I'm guessing controls the 'on/off' and the variable speed). Looking closely at the circuit board I can clearly see parts have physically blown. One part (after some research) looks like a flat foil capacitor labelled '104J63'. The other part that is blown I'm not too sure what it is. Is it attached to the board with yellow stuff and the label where it is in the board is slightly obscured. I think it says TH1. The whole side of the part is blown so I don't know any numbers for it. I do remember a small black piece falling out later on but I can't remember if I kept it or not. I'm a bit stuck as to what it is so this seemed the best place to find some help.

    I've attached some photos I've taken. I was also wondering could I just take out the circuit all together or would that just blow the whole thing up!?

    Any help would be very much appreciated.

    Thanks in advance.
     

    Attached Files:

    Last edited: Mar 8, 2012
  2. siggy

    siggy

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    3
    Mar 3, 2012
    Th1 could be a thyristor
     
  3. siggy

    siggy

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    Mar 3, 2012
    Do you have a model number?
     
  4. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    Model number for the part? No, if you look in the 2nd photo the side has blown off :(
     
  5. siggy

    siggy

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    Mar 3, 2012
    Oh I see you mentioned rt650 in the title have you googled try terms like repair circuit diagrams etc
     
  6. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    Yes, i've done all that and found nothing. I've contacted Black and Decker and even 'Defond' who's name is on the circuit board. Black and Decker said they only supply the whole unit and not just the circuit board. Defond have not got back to me.

    I have a multimeter to check parts. The blown capacitor I can get with thanks from the link posted. It's the other blown part which does look like a 'Thyristor' as stated above too but which one I have no idea. Would a multimeter be able to tell me a value etc? As I do have a multimeter.
     
  7. siggy

    siggy

    36
    3
    Mar 3, 2012
    You could try but if its blown you may not get anything

    I.e completely shorted or open circuit

    Tried looking for a busted one from eblag? Might be able to swop components unless the same components are blown
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Take another photo like the third, but showing the bottom of the board.

    Does the motor turn freely?
     
  9. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    I'll do that tomorrow and upload it.

    Yes, I connected it up to a small 9v battery (only thing I had to hand) and it turned slowly.

    I've been looking closely at the broken 'Thyristor' and the logo on it is 'STMicroelectronics'. It has 3 rows of print. First ends in what looks like a 4'. Second looks the end of the word Morocco (I've seen that on others). And the 3rd looks like it ends in a 9.
     
    Last edited by a moderator: Mar 5, 2012
  10. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    I have been looking at STMicroelectronics Thyristors and have narrowed it down to BTA24 25A Snubberless™ Triacs. (using the number 4 from the first line of the broken part only one ends in a 4)

    Description
    Available either in through-hole or surface-mount packages, the BTA24, BTB24, BTA25, BTA26, BTB26 and T25 triac series is suitable for general purpose mains power AC switching.

    Key Features
    High current triac
    Low thermal resistance with clip bonding
    High commutation (4 quadrant) or very high commutation (3 quadrant) capability
    BTA series UL1557 certified (File ref: 81734)
    Packages are RoHS (2002/95/EC) compliant

    Does this read as though it would replace the broken one?
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,361
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    Jan 21, 2010
    Great. It's almost certainly a triac, and again, almost certainly something which can be replaced without knowing *exactly* what the original part was. The copper side of the board will help in confirming this.

    What voltage is your mains?
     
  12. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    On the spec sheet it states voltage as 230v and power as 90w if that helps.

    Thanks for all your help so far.
     
  13. gpatel_uk

    gpatel_uk

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    0
    Mar 4, 2012
    I've uploaded a new photo of the copper side of the board. I've also placed a red line around where the part is soldered in.

    Thanks.
     
    Last edited: Mar 5, 2012
  14. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,361
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    Jan 21, 2010
    From my brief examination, if it is one of the triacs mentioned above, then the gate seems to be connected to the right stuff on the board.

    I'd get the TO-220 insulated tab version BTA24 and give it a go. My concern is that something else has failed and a new triac will blow immediately, but if the motor works, I'm not sure what else could be at fault...
     
  15. gpatel_uk

    gpatel_uk

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    Mar 4, 2012
    Thanks for helping me with this.

    So would this be ok? http://uk.farnell.com/stmicroelectronics/bta24-600bwrg/triac-24a-600v-to-220ab/dp/1057284 Only £1.68 so I can afford to buy more than one if it does blow right away.

    Also the capacitor with the label '104J63' is blown as shown in photo1. So would this be a correct replacement too?

    http://uk.farnell.com/jsp/displayProduct.jsp?sku=1614309&action=view&CMP=GRHB-FINDCHIPS2-1002791 Unit price 0.68p. But these have a postage charge of £15.95! as they come from america.

    So comparing spec I found this http://uk.farnell.com/arcotronics/r82dc3100z350j/capacitor-0-1uf-63v-5mmp/dp/1679402 The only difference is the 'Life time @ temperature'. This one is 2000 hours @ 105°C and the one from the USA is 2000 hours @ 85°C. My thoughts are being a higher temperature is better than being below. £0.097p minimum 10 ordering will again not be a hardship.

    If you can confirm the triac and capacitor (from UK) are ok (as I don't want to order the wrong ones) I'll go ahead and order them to give it a try.

    Once again I appreciate your help very much!!
     
  16. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,361
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    Jan 21, 2010
    Yeah, the capacitor looks about right. 105C is better than 85C, correct.

    My only concern would be that the lead spacing is correct, but even that's not a huge problem. I guess the original part has a lead spacing close to 5mm.
     
  17. gpatel_uk

    gpatel_uk

    40
    0
    Mar 4, 2012
    Parts have been ordered and I pick them up tomorrow. Thank you once again.
     
  18. gpatel_uk

    gpatel_uk

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    0
    Mar 4, 2012
    I've just replaced the broken parts. The capacitor was exactly the same size so slotted in easily. After scraping away the hard glue around the triac I pulled it out. The replacement triac was a lot bigger than the original but it did fit in fine.

    I turned the unit on and for a split second the motor turned but then was dead. I could not even feel the power in the unit like it was jammed before. It was all dead now.

    I've taken another look and used a multimeter to measure everything. The only thing that does not have a value is one resistor. On photo 1 its the nearest one to the camera. It comes up with a value of zero. Does that mean it needs replacing too? Sorry I'm not very good at this am I? haha!

    The new parts seem ok and have not blown again.

    Anymore help would be great. Thank you.
     
  19. siggy

    siggy

    36
    3
    Mar 3, 2012
    If it is zero ...........it isnt a resistor
     
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