I Killed a 7950TH!

[hpiguy]

Over the holidays I smoked the 7950TH in my Wraith. I did the same conformal coating on it that I did on everything else (everything else is still working just fine), the only exception being that I added some dielectric grease on top of the board as well. It was literally so hot it branded me when it died. Was the combination of conformal coating and dielectric grease both too much for it? It only had 8-10 packs through it, that gets expensive fast.

[ittybitty]

I'm curious why you did all of that to a 7950TH...

If you were trying to waterproof it all you needed to do was use something like silicone around the case joints, and maybe some grease around the output gear.

What were you doing to it when it died?

[axial 4x4 crawler]

Do you have a BEC? I have the 7980th on my wraith (strongest you can buy) and it has never let me down. But if you ran through water, I would have opened it up and put marine grease in the gears (not to much) and then dip the entire servo in plasti dip . This will create a outer layer of protection, dip it again if you liked to gain more protection. Then let it dry and peal the plasti dip off were the servo horn goes. With the servo protected on the inside and outside you should be good to go man. Warning if you have a warranty of some sort it could void it. But all you can do know is replace with another 7950th or just buy a 7980th (these are oversized and will be quite large for the wraith). By the way I would use "plasti dip" that grease you used doesn't last!!(From my experience) Hope this helped,
- axial 4x4 crawler

[Wicked Monkey]

I know a guy that smoked two of them 1 right after the other almost. And he hadn't done anything to them. Just some serious strain. He's a little easier on them now, I hope anyway.

[mammoth]

Not indestructible servo but will take a beating thats for sure. I have killed the gears in one and a board in another but I am very hard on them with my wraith. Pro4 on 3s launching 10-15 feet in the air then watch it tumble hard down the hill or rocks.
No need to take it apart to wp it just like said above do the seams and some grease ag the output and you should be good to go!!!

[Ty]

Check output voltage of the bec. Mine went bad and was sending full 3s to the servo. It was hot also!!! Ty

[hpiguy]

I was crawling when it happened. Everyone has their version of how to waterproof things I suppose. Again I was using conformal coating, and the grease, not just the grease. Servo was ran off a CC BEC set at 7.2v, and end points were set correctly also. It never touched water, as it didn't last long enough to make it to the water. It's being replaced with a Savox, as the Savox I waterproofed three weeks ago that's been sitting in a glass of water the whole time is still going strong. I'll check the BEC voltage, if it malfunctioned and fried the servo I'll be pissed.

[axial 4x4 crawler]

Savox is a great brand, I'm going to replace my ridgecrests servo because the stock one can't turn my waited tires. So a Savox 1230sg or what ever the model is. Has 500 oz. (At 6 volts) Of torque and is only 75 at amainhobbies.com, defiantly worth looking into buying, I also recommend a locking aluminum servo horn for your wraith, as strong servos demolish plastic horns, hope this helped, - axial 4x4 crawler

[Diablo666]

Just find a good hitec dealer and send it back for a rebuild. Doesn't hurt to try.

[jaloos]

Originally Posted by axial 4x4 crawler

Savox is a great brand, I'm going to replace my ridgecrests servo because the stock one can't turn my waited tires. So a Savox 1230sg or what ever the model is. Has 500 oz. (At 6 volts) Of torque and is only 75 at amainhobbies.com, defiantly worth looking into buying, I also recommend a locking aluminum servo horn for your wraith, as strong servos demolish plastic horns, hope this helped, - axial 4x4 crawler

Got 4 of the Savox SA-1230SG Monster Torque servos and not a problem so far. A little noisy but works great.

Savox SA1230SG Digital Servo

Check the dimensions though I believe it is a little taller than a standard size.

[axial 4x4 crawler]

Yeah your right about the dimensions, but on my wraith I have a hitec 7980th and that thing is huge..... haha but anyways the hitec is larger than the savox so it should fit and on my wraith I just took two screws off the servo mount because it can only hold two. But I am getting VP trusses because I have experienced the trusses stripping out caused by the servo being so strong on my wraith, and yes it did strip a truss out but with titanium trusses it will be bulletproof in the front. But I only bought the one hitec and can't afford them anymore unless I have to, thanks - axial 4x4 crawler

[Tgreer]

I had the same thing happen to mine. Brand new 7950th and 2/3 into a lap at an ultra4 type race the wheels where stuck turned at full right. I reached down and grabbed the servo and burned the piss out of my fingers. I sent the servo off to hitec, and no questions asked they fixed it and returned it and I have had no problems since.

[hpiguy]

I was running a Robitronic arm on it.

I'll probably send it in after the holidays, as there will most likely be a charge for it.

I ordered a Savox 1231SG, but after a second look, I doubt it will fit as I'm running a CMS setup. Looks like I'll be sending it back and ordering something else. Not having a LHS anymore is getting really old.

I also got branded when I touched mine LOL.

[hpiguy]

Well, I finally got a chance to tear into the Wraith to check things. The BEC is good, dead on matter of fact. I did however find this, my RX bypass adapter negative lead on the BEC side was holding on by about two strands. Could this have led to the issue, or just a byproduct of the servo frying?

[Charlie-III]

It may have helped undervolt the servo under load.
If it was fryed by the servo dieing, it would likely have melted the insulation on the wire which I don't see in that pic.

[hpiguy]

Good point, thanks Charlie. The insulation was fine on all the wires actually. It makes me wonder if the whole wire was ever in there when it was crimped now. All the other connections are solid when I pull on them, so I'll likely split the black wire and solder them together for a more solid setup.