Troubleshooting help needed on AnthroDesk motorized standing desk

Thread Starter

Ambermeows

Joined Jan 24, 2021
6
Hi all, I’m new to this and I was wondering if anyone can help me in troubleshooting a possible broken component. This is the pcb for my dual standing desk that recently broke down. The left leg of my desk does not go up or down because something got in the way while the desk was going down. I opened the control box and examined the board and saw that something might have burned out on the board.
My guess is that the chip below the IC3 might’ve burned.

I am new to this and is willing to learn on how to fix this issue. Any help is appreciated, thank you!
07C84253-C973-4613-B889-AAEBCA9ED92B.jpeg
 

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MrChips

Joined Oct 2, 2009
23,515
Welcome to AAC!

Let's start with the make and model of the stacking desk if that is available. Then we edit the title to one that gives more meaningful information.
Nice sharp photos, btw.
 

SamR

Joined Mar 19, 2019
3,405
Looks like liquid damage to me between IC3 and IC1. Take a Qtip and swab the area with some isopropyl alcohol and see if you can clean it up to see if there is any damage to the traces.
 

wayneh

Joined Sep 9, 2010
17,152
My guess is that the chip below the IC3 might’ve burned.
You might be right, but I suspect the problem is elsewhere. I'd like to see the rest of the board, especially any large-ish transistors (3-pins) you see.

The problem may not be on the board at all. Stalling a motor causes a high current in the power components, and that in turn causes heat. So it could be a blown transistor, but it could also be a thermal fuse blown inside the motor. Or (hopefully not) a blown motor winding. Maybe there's a fuse blown somewhere.
 

Thread Starter

Ambermeows

Joined Jan 24, 2021
6
Thank you! The make and model of this standing is Anthrodesk programmable dual motor electric silver standing desk. I can’t find the exact model but this is what is on the control box: TiMotion model no: TC15-L.

I hope this helps... bought this product from Amazon, but the also got rid of the item, so that’s the name of the product from the order history.

thank you for the help.

Welcome to AAC!

Let's start with the make and model of the stacking desk if that is available. Then we edit the title to one that gives more meaningful information.
Nice sharp photos, btw.
 

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Thread Starter

Ambermeows

Joined Jan 24, 2021
6
Thanks for replying! I will do that once I get isopropyl alcohol. I am new to this, so what exactly am I examining for when I clean the area with alcohol? And are the traces the silver pins holding the chip?

Looks like liquid damage to me between IC3 and IC1. Take a Qtip and swab the area with some isopropyl alcohol and see if you can clean it up to see if there is any damage to the traces.
 

Thread Starter

Ambermeows

Joined Jan 24, 2021
6
Here are the photos of the motors as well as the power supply. I have used a multimeter to check the connectivity of the 3 little capacitors and they seem to be working... because the multimeter was making a solid sound. Not sure if I am right or doing that process right though.

the issue started happening when I retracted the desk back to the lowest setting and on its way back down I had forgotten to clear the path and had a bag full of stuff that was caught on the leg. I didn’t have enough time to stop the device so I just pulled my bag out of the way as it continued to descend... ever since that happened, the left side seem to not operate anymore but the right side of the leg is still responsive. And since it’s dual motors the right side will not move up unless the left side will move as well.

I hope the images will help. Please let me know if you need any thing else.

thanks for the help!
You might be right, but I suspect the problem is elsewhere. I'd like to see the rest of the board, especially any large-ish transistors (3-pins) you see.

The problem may not be on the board at all. Stalling a motor causes a high current in the power components, and that in turn causes heat. So it could be a blown transistor, but it could also be a thermal fuse blown inside the motor. Or (hopefully not) a blown motor winding. Maybe there's a fuse blown somewhere.
 

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SamR

Joined Mar 19, 2019
3,405
The white residue in these areas. I'd give the entire area a good cleaning and check for any damage. Watch out for rubbing alcohol as it contains additives such as witch hazel and etc. Use as high of a percentage of alcohol as you can find. Drugstore 70% Isopropyl Alcohol works as long as it has no additives other than water. Yes, the silver bars are where the chip is soldered to the board.

screenshot.png
 

MrChips

Joined Oct 2, 2009
23,515
I have used a multimeter to check the connectivity of the 3 little capacitors and they seem to be working... because the multimeter was making a solid sound. Not sure if I am right or doing that process right though.
That is not a valid test. You cannot test capacitors in that manner. The only thing the test indicates is that you have a low resistance path between your two test points. A capacitor that has failed to a dead short will give the same response, i.e. the multimeter will beep when in continuity test mode.

In addition to the above, using a multimeter in the continuity test more or in resistance measurement mode in order to test a component in-circuit will be influenced by the rest of the circuitry that is connected to the component. The proper way to test a component is to remove the component from the circuit, or at least detach all but one leg of the component from the circuit.
 

sagor

Joined Mar 10, 2019
439
The output of the ULN2003 is along the top, 4 lines driving something that is on the other side of the board under D9, D10, D11 and D12. If anything is blown from an overload, odds are it will be what is on the other side of the board from those diodes. I suspect some transistor/MOSFET. The diodes are likely back emf suppressors.
If the power supply checks out good, check those devices under D9-D12
 

Thread Starter

Ambermeows

Joined Jan 24, 2021
6
Thanks for the reply. How would i go about checking if the power supply is good?

The output of the ULN2003 is along the top, 4 lines driving something that is on the other side of the board under D9, D10, D11 and D12. If anything is blown from an overload, odds are it will be what is on the other side of the board from those diodes. I suspect some transistor/MOSFET. The diodes are likely back emf suppressors.
If the power supply checks out good, check those devices under D9-D12
 

sagor

Joined Mar 10, 2019
439
Thanks for the reply. How would i go about checking if the power supply is good?
Hm, I think those 4 devices I mentioned before are the black relays and those are not likely gone "bad" (in most cases). Checking power supply involves measuring the output voltages first. See if they are within proper ranges. For example, if the relays are labelled 12V, then there should be a +12V output somewhere on the power supply. Same logic applies if the relays are 24V, 5V, and so on. The power supply has 2 large red/black wires to the supply power to "something". That voltage may also pass through those two TO-220 devices (transistors or MOSFETs) with heatsinks. The other 3 wires seem to be control signals, and will usually be in the +5V to +24V range. If you get no voltages on those wires, relative to the black wires (I'm assuming black is ground/return), then check the fuses on the input side of the power supply. There seems to be a small brown device, which may be a fuse or a reset-able fuse.
Good luck.
 
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