heat sink questions

[boosted escort]

I bought a ms1 used. I am converting it to ms2 and am going to run the gslender firmware on it. Anyway I was looking at the heat sink and it has this cloth like substance under the transistors. Can anyone tell me what this is and if I need to remove it. The msextra manuals say nothing about it so I assume it is not recommended. Also tip120 is soldered in the proto area without a heat sink is this bad? Here is a picture of my board.

https://db.tt/s8yIypvF

[slow_hemi6]

The cloth is probably silicone insulator or maybe mica but mica is more plastic like and translucent. Either way some components need to be isolated from the heat sink and require the insulator. This can be more the case when component substitution has also occurred.

[boosted escort]

So do you think I need to redo the heatsink

[slow_hemi6]

Well that stuff does not look like it has very good thermal transfer characteristics to me. If it is cloth like then it could also be a moisture trap and lead to shorting of the tabs to the heatsink. So if I was you then yes I would redo that.

[DaveEFI]

So do you think I need to redo the heatsink

Difficult to tell by that picture, but if you use steel screws on a device which needs to be insulated, they normally use plastic bushes to insulate the screw from the transistor.
They come as part of a fitting kit for that transistor type. Or use nylon screws.

Personally, I'd remove that cloth or whatever and only use insulation (fitting kits) where needed. And use contact grease between the device and heatsink everywhere.