I thought the bec was only good for up to 4s then you needed an external one above that voltage. Which might be causing the esc to thermal more often. I wouldn't say it is the only reason it's thermalling, just it's not helping.

Neil... I opened the esc today and found that the thermal tape was not sticking to the casing the way it should, 1/3 of the pad is covered with dirt, leading me to believe the FETs were overheating quite a bit... I am hoping this is the worst case... I am also thinking cogging is attributed to gearing... Mike shipped the new pinions for me this week, so I hope when I get everything back together the smaller pinions will help to reduce cogging... Is there an easy and safe way to remove the heat spreader from the FETs... and if it's really stock on there... should I bother to remove it?


Hey Pinkpanda... I'm actually using an external BEC... I clipped the red wire on the receiver lead to disable the internal BEC.

A few pics (I hope it's ok to post photos here):


http://lh5.ggpht.com/_4vPm5E8J5HA/Sv...0/DSC_0003.JPG




http://lh4.ggpht.com/_4vPm5E8J5HA/Sv...0/DSC_0004.JPG

Yep, that thermal tape is not the best stuff. It's kinda too bad that this ESC almost requires the internal mod, but once done, it works well even long-term. I still have two 125's that are fully operational as of today.

Panda: All the Quark xxB line ESCs use a linear BEC. And like all linear BECs, should be disabled in lieu of an external one on anything above 2s lipo or 7-8 cells NiMH.

Hmmm... Not the best design in the world I guess... should I remove the upper board to get to the other spreader? I notice they're some pins connecting the upper and lower boards... Or is it not that simple? It feels real uncomfortable trying to remove the lower spreader, it's really on there.

In all the mods I've done, I leave the middle one alone. It tends to stay put since it's not used to hold the ESC in place. The lower spreader can be tricky to remove. I usually heat the spreader a bit to make the thermal pad adhesive a little more pliable. Even then you have to be careful not to damage one of the FETs.

Cool BrianG... I'll see how it goes when I get some more time to work on it.

Ok... I got the slab off with ease after applying a some heat from a heat gun last night... I'll cut the new slab tomorrow and get some thermal grease for the reassemble.

If it comes off that easily with just a little heat, no wonder the pad doesn't hold during use since those FETs can get pretty hot. Don't know if you've seen this, but the pic below shows the proper dimensions for the new spreader plate when not using the thick thermal pads:

http://scriptasylum.com/forumpics/quark_mod.gif

Yep... It was quite disturbing to see how easy it it came off when I used the heat gun... I saw your diagram before when I started researching on this mod... nice illustration. I have a small sheet of 3/16 aluminum
(not much thicker than 1/8) That I think will work just fine after some light sanding and polishing. I am not sure if we have the popular 'ARCTIC ALUMINA' in the island... so I will have to settle with the generic brands.

Just be aware that you have to use thermal epoxy, not regular thermal compound. It has to hold the guts to the case.

hmmm... noted...