Author Topic: How to remove transistor heatsink clamp  (Read 1620 times)

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Offline technovikingTopic starter

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How to remove transistor heatsink clamp
« on: September 26, 2021, 09:33:05 am »
I've got a motor controller that let out the smoke that I'd like to attempt to repair. The problem is that it is housed in an aluminium extrusion with the mosfets clipped to the housing and I have no real idea how to remove or re-install the clips.

I´ve seen guides online on how to do this for clips that have a little slot in them, but these don't have that.
If it's of any help the clips model number is MAX02H
« Last Edit: September 26, 2021, 09:34:54 am by technoviking »
 

Offline technovikingTopic starter

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Re: How to remove transistor heatsink clamp
« Reply #1 on: September 26, 2021, 09:39:53 am »
For the curios this is where the smoke escaped. I'm taking any bets on what took out what, Capacitor vs NTC
 

Online jpanhalt

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Re: How to remove transistor heatsink clamp
« Reply #2 on: September 26, 2021, 09:58:48 am »
The retainers look like they are simply held by spring compression between two narrow fins.  A little wiggling will remove them.

The bigger question is why do you want to remove them?  That is not where the problem was.  That disk shaped thing is probably some sort of protective element like a MOV (https://en.wikipedia.org/wiki/Varistor).
 

Offline strawberry

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Re: How to remove transistor heatsink clamp
« Reply #3 on: September 26, 2021, 10:51:14 am »
NTC inrush current limiting resistor.
 

Offline xrunner

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Re: How to remove transistor heatsink clamp
« Reply #4 on: September 26, 2021, 11:12:26 am »
The bigger question is why do you want to remove them?  That is not where the problem was. 

How is he going to repair the board (replace components) without removing it?  :-//
I told my friends I could teach them to be funny, but they all just laughed at me.
 

Offline DavidAlfa

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Re: How to remove transistor heatsink clamp
« Reply #5 on: September 27, 2021, 12:40:55 am »
NTC inrush current limiting resistor.

It also could be a VDR, to mitigate voltage spikes. They have very similar packaging.
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Offline fzabkar

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Re: How to remove transistor heatsink clamp
« Reply #6 on: September 27, 2021, 03:59:57 am »
NTC inrush current limiting resistor.

It also could be a VDR, to mitigate voltage spikes. They have very similar packaging.

There is "NTC1" marked on the PCB nearby.
 

Offline BrokenYugo

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Re: How to remove transistor heatsink clamp
« Reply #7 on: September 27, 2021, 04:42:20 am »
Looks like you just slip a screwdriver between the heatsink and clip and pry it out of the groove.
 

Online Ian.M

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Re: How to remove transistor heatsink clamp
« Reply #8 on: September 27, 2021, 05:57:14 am »
Prying them out would probably distort the spring clips or damage the groove in the heatsink they are press-fitted into. Instead lift them all slightly, by sliding in the shaft of a screwdriver (or other smooth cylinder with a chamfered end) of a diameter that just lifts the clips off the transistor bodies, then you should be able to slide the board out cleanly, though if its been undisturbed for years, you may have to pry gently to unstick each transistor from the silpad.
 

Offline Alti

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Re: How to remove transistor heatsink clamp
« Reply #9 on: September 27, 2021, 08:01:25 am »
Link to MAX CLIP
From their "Clip and Rail Thermal Solutions":
Quote
Clip solutions can also simplify ongoing equipment maintenance as they
are significantly easier to disassemble and reassemble than their rivet- and screw-based counterparts.
However, I have not been able to find any explanation about how to actually unclip this thing without damage.
 

Online perieanuo

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Re: How to remove transistor heatsink clamp
« Reply #10 on: September 27, 2021, 09:22:46 am »
slide them one by one, but i think they will block in that aluminium

another way is to pull him out with something like a bent plier (dunno how the call this in english sorry)

or, if the shorted transistor is in the middle, cut his legs, remove it, then the clip will come out easily because the 'spring' will be not tensioned. that's my option no 1 cause i'm lazy
 

Online perieanuo

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Re: How to remove transistor heatsink clamp
« Reply #11 on: September 27, 2021, 09:48:57 am »
 
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Offline aqibi2000

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Re: How to remove transistor heatsink clamp
« Reply #12 on: October 02, 2021, 12:03:12 pm »
Pull out with pliers mate
Tinkerer’
 

Offline Audiorepair

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Re: How to remove transistor heatsink clamp
« Reply #13 on: October 02, 2021, 06:57:41 pm »
Angle grinder.
 

Online WattsThat

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Re: How to remove transistor heatsink clamp
« Reply #14 on: October 03, 2021, 02:38:42 am »
Commonly used on small inverters (<1kw).

You’ve got to pry them out from the back of the top slot. A sacrificial ~2.5mm flat bladed screwdriver works well, slid in behind the smaller curled top. The clips can be reused, the silpads usually don’t fair so well.
« Last Edit: October 03, 2021, 02:40:57 am by WattsThat »
 

Offline CJay

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Re: How to remove transistor heatsink clamp
« Reply #15 on: October 03, 2021, 09:48:50 am »
Plasma cutter.

Seriously though, they're pushed in, they pull out.
 

Offline Dacke

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Re: How to remove transistor heatsink clamp
« Reply #16 on: October 03, 2021, 05:34:45 pm »
Arc furnace.

Or pliers
 


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