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#1 |
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Join Date: Nov 2009
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![]() I have a Dewalt / Black and Decker 40V trimmer model LST136 Type-1.
It stopped working. Trimmer motor tests fine. I opened it up to find that the controller board had a blown component at position Q5. It also looks like a similar component at D6 has a bulging area. These two mosfets? are attached to a heat sink. The D6 component looks to be a MBR20100CTP rectifier. The Q5 component blew apart, so its difficult to read the label. I am hoping to get help identifying the Q5 component. Pictures are attached. In the photos, the heatsink and the Q5 component have already been removed from the board. One of the three legs broke off of the Q5 component. The last 2 pics are of the component I need help identifying. Last edited by braxton; 08-10-2021 at 09:01 AM.. Reason: corrections and additions |
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#2 |
Great Sage 齊天大聖
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![]() 100v is too low for a schottky diode - 250v atleast.
ideally 10x the running voltage! |
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#3 | |
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![]() Quote:
Any idea what Q5 is? I am attaching two more photos of the board Last edited by braxton; 08-10-2021 at 09:21 AM.. |
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#4 |
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![]() Be careful with protection boards when repairing them make sure that the battery are not fully charged if necessary run them down to 3.2 volt and be ready to remove it from the tool or the charger if something goes horrible wrong
I have repair Ryobi battery packs sometimes you can repair them sometimes not
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9 PC LCD Monitor 6 LCD Flat Screen TV 30 Desk Top Switching Power Supply 10 Battery Charger Switching Power Supply for Power Tool 6 18v Lithium Battery Power Boards for Tool Battery Packs 1 XBox 360 Switching Power Supply and M Board 25 Servo Drives 220/460 3 Phase 6 De-soldering Station Switching Power Supply 1 Power Supply 1 Dell Mother Board 15 Computer Power Supply 1 HP Printer Supply & Control Board * lighting finished it * These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10% 1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later ) 2 Hem Saw Computer Stack Board All of these had ![]() All of the mosfet that are taken out by bad caps ![]() |
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#5 |
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#6 |
Badcaps Veteran
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![]() I just noticed that this battery pack is 40 volts which I do not have
Just be aware of this if this is an older battery pack the controller board of a new one might not be the same as one you have Last edited by sam_sam_sam; 08-12-2021 at 08:24 AM.. |
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#7 |
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![]() Here are photos of the trimmer with the model number.
The board is from inside the handle part. The board is not from the battery itself. Last edited by braxton; 08-12-2021 at 08:52 AM.. Reason: Addition |
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#8 |
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![]() Based on a closer look at the blown chip, it looks like it is an Infineon IRL3705Z mosfet.
Digikey lists it as obsolete. Can anyone help out finding this part or an equivalent? Thanks. |
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#9 | |
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![]() Quote:
Digikey IRL3705ZPBF-ND direct replacement, in stock |
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#10 |
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#11 |
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![]() Check the gate drive circuit resistor (R24) to make sure it is not open, When the mosfet shorted, many times it also takes out the drive ic, that sot23-5, best to get it's number before it is also unreadable.
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#12 |
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![]() This means that the charger has the protection board and the battery has no protection board might not even have a protection fuse in it
When you test this board be careful and be ready to disconnect the battery very quickly if something goes horrible wrong |
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#13 |
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#14 |
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![]() The sot23-5 chip is hard to read but it looks like GX3mD maybe?
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#15 |
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![]() Replacing the 2 chips had no effect. Still dead.
What about this component (largest chip in the corner) in the attached photo? Last edited by braxton; 08-13-2021 at 05:43 PM.. |
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#16 |
Great Sage 齊天大聖
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![]() the "dale" part is a resistor - it should look like a short circuit.
clean the board with alcahol - it's hard to see the parts clearly. |
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#17 |
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![]() After a closer look R24 is likely the resistor between the mosfet source pin (Dale resistor) and the CS pin of the ic, and not the gate drive resistor. Check that the resistors between the gate and the ic are ok.
Last edited by R_J; 08-13-2021 at 10:21 PM.. |
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#18 | |
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![]() Quote:
I also measured all of the resistors on the board and all seem to give an ohms reading (Highest was 100K and none seem to be open as far as I can tell). |
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#19 |
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![]() what about these solder joints ?
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#20 |
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