RCCrawler Forums

kevinlongisland · 10-01-2006, 07:44 PM

I've had two 5995tg robot servos overheat and fail on me during the peak of the Arizona heat. On both occasions the servos failed when used under continuous use. What I mean by continuous use is running complete battery packs down, putting in another battery pack, and crawling again. In comparison, my robot servos lasted for over a year when only being used for competition. During competition I only run about 1/2 a battery pack down, then the truck sits for at least 15 minutes or more.

There may have been more than one failure mode on the servo, but from the pictures you can see an obvious failure point. The semiconductor device on the open face of the board failed. After replacing the servo I noticed the new servo got very hot around this area. This semiconductor does not have a good path for heat to conduct away.

After analyzing the problem I came up with the following solution. An electrically non-conductive thermal transfer compound would help draw heat away from the semiconductor device and into it's surrounding components and the case (and into the atmosphere). You can purchase thermal transfer compound from most electronic outlets. This compound is often used on computer CPU's to help transfer heat. I've tested this with good results, although further testing is needed.

The first two photos show a servo that has failed. The following photos show my application of the thermal transfer compound. Put enough thermal transfer compound on the board to contact the back cover when you re-install it. That's it. The compound will help transfer heat away from this critical component and hopefully stop your servo from failing.

kevinlongisland · 10-01-2006, 07:48 PM

Shot of a good circuit board:

SVEN · 10-01-2006, 08:00 PM

Great information, thanks. I have been running my truck only during comps so far (with the 5995's), but now that the season is over I will probably be driving a little different.

Does the compound become hard like silicon rubber, or will it remain in a liquid type state? Just wondering if I will need to put the servo back together in a certain time frame.

kevinlongisland · 10-01-2006, 08:30 PM

The compound does not dry while you are applying it. You do not have to hurry to get the cover back on.

http://www.arcticsilver.com/arctic_alumina.htm

Controlled triple phase viscosity:
Arctic Alumina does not contain any silicone. The suspension fluid is a proprietary mixture of advanced polysynthetic oils that work together to provide three distinctive functional phases. As it comes from the tube, Arctic Alumina's consistency is engineered for easy application in a thin even layer. During the CPU's initial use, the compound thins out to enhance the filling of the microscopic valleys and ensure the best physical contact between the heatsink and the CPU core. Then the compound thickens slightly over the next 50 to 200 hours of use to its final consistency designed for long-term stability.

Link · 10-01-2006, 09:04 PM

Stuff like that happens out here when your thermometer looks like this,

Highmark · 10-01-2006, 09:35 PM

120K? Must be a rotary....

Unholy · 10-01-2006, 09:54 PM

Great Idea!

Just be carefull that you use a high quality, NON-CONDUCTIVE & NON-CAPACITIVE product... or your fix will not work so well.

Kevin posted a product that fits that bill, don't think you can use any old thermal paste and it will work with the same results!

_Jason_ · 10-02-2006, 12:12 PM

Quote:

Originally Posted by Highmark

120K? Must be a rotary....

yep 12,500 all day

EeePee · 10-02-2006, 04:27 PM

What about then sticking a heatsink on the back of the servo case?

kevinlongisland · 10-02-2006, 06:24 PM

Quote:

Originally Posted by EeePee

What about then sticking a heatsink on the back of the servo case?

That would further increase heat dissipation into the atmosphere. But today's semiconductors are made to run at really high temperatures. If the heat transfer compound solves the problem it wouldn't be worth it putting a heat-sink on the back cover.

EeePee · 10-02-2006, 07:59 PM

Are you making that up?

666 · 10-02-2006, 08:02 PM

What did you do to repair the burned up servo? I have 2 5995's like that, but my 5955's never burn up?

Link · 10-02-2006, 08:59 PM

Quote:

Originally Posted by Highmark

120K? Must be a rotary....

No that would be 120F in the shade.

JasonInAugusta · 10-02-2006, 09:28 PM

A pair of 94359Zs would fix that too! ;)

TXT-666, you don't repair them, the FETs are gone. You can send'm to hitec for repair.

Heat is the absolute enemy of a semiconductor...

kevinlongisland · 10-03-2006, 10:03 AM

You can buy this version online if you can't find it locally:

http://www.radioshack.com/product/in...entPage=search

Arctic Silver® Ceramique Thermal Compound

Electrical Insulator:
Céramique does not contain any metal or other electrically conductive materials. It is a pure electrical insulator, neither electrically conductive nor capacitive.

Stormin2u · 07-28-2007, 07:26 PM

Kevin,

That was a great thread I have been looking for a new more powerful servo and I like the Hitec 5995 but I was concerned about it overheating.

My Futaba Magnum 2PL has epa so I should be able to cut the 180 degree rotation to something closer to 45 or 50.

I'll be ordering one soon TCS of course

Thanks Stormin'

Kamikaze · 07-28-2007, 07:40 PM

I got a pair of these from Kevin for my super, they are top notch for sure. Just be sure to keep your fingers away from them.........:-(

kevinlongisland · 07-31-2007, 08:06 PM

Quote:

Originally Posted by Kamikaze

I got a pair of these from Kevin for my super, they are top notch for sure. Just be sure to keep your fingers away from them.........:-(

LOL! When I first got a robot servo I wanted to see much torque it had. So I tried to stop it with my thumb. It almost broke my thumb! Yup, keep fingers away from robot servos!!!!

renoirbud · 08-13-2007, 01:37 PM

hey there

How many servos can be treated with each tube of the Radio shack stuff?

I might as well do all my robot servos at the same time.

Thank you in advance.

Rene

kevinlongisland · 08-13-2007, 07:50 PM

The last time I did one I put the whole tube in there. It filled the entire area inside. I think that will provide the most protection.

10-01-2006, 07:44 PM	#1
kevinlongisland The Wheels Keep Turning Join Date: Jan 2004 Location: Phoenix, Arizona Posts: 2,831	Hitec 5995tg Robot Servo Fix - Help save your robot servo from overheating I've had two 5995tg robot servos overheat and fail on me during the peak of the Arizona heat. On both occasions the servos failed when used under continuous use. What I mean by continuous use is running complete battery packs down, putting in another battery pack, and crawling again. In comparison, my robot servos lasted for over a year when only being used for competition. During competition I only run about 1/2 a battery pack down, then the truck sits for at least 15 minutes or more. There may have been more than one failure mode on the servo, but from the pictures you can see an obvious failure point. The semiconductor device on the open face of the board failed. After replacing the servo I noticed the new servo got very hot around this area. This semiconductor does not have a good path for heat to conduct away. After analyzing the problem I came up with the following solution. An electrically non-conductive thermal transfer compound would help draw heat away from the semiconductor device and into it's surrounding components and the case (and into the atmosphere). You can purchase thermal transfer compound from most electronic outlets. This compound is often used on computer CPU's to help transfer heat. I've tested this with good results, although further testing is needed. The first two photos show a servo that has failed. The following photos show my application of the thermal transfer compound. Put enough thermal transfer compound on the board to contact the back cover when you re-install it. That's it. The compound will help transfer heat away from this critical component and hopefully stop your servo from failing. Attached Images Last edited by kevinlongisland; 10-01-2006 at 07:46 PM.

10-01-2006, 07:48 PM	#2
kevinlongisland The Wheels Keep Turning Join Date: Jan 2004 Location: Phoenix, Arizona Posts: 2,831	Shot of a good circuit board: Attached Images

10-01-2006, 09:04 PM	#5
Link Quarry Creeper Join Date: Jul 2006 Location: N. Phoenix Posts: 440	Stuff like that happens out here when your thermometer looks like this, Attached Images

10-01-2006, 08:00 PM	#3
SVEN I wanna be Dave Join Date: Feb 2005 Location: Burnsville Posts: 3,096	Great information, thanks. I have been running my truck only during comps so far (with the 5995's), but now that the season is over I will probably be driving a little different. Does the compound become hard like silicon rubber, or will it remain in a liquid type state? Just wondering if I will need to put the servo back together in a certain time frame.

10-01-2006, 08:30 PM	#4
kevinlongisland The Wheels Keep Turning Join Date: Jan 2004 Location: Phoenix, Arizona Posts: 2,831	The compound does not dry while you are applying it. You do not have to hurry to get the cover back on. http://www.arcticsilver.com/arctic_alumina.htm Controlled triple phase viscosity: Arctic Alumina does not contain any silicone. The suspension fluid is a proprietary mixture of advanced polysynthetic oils that work together to provide three distinctive functional phases. As it comes from the tube, Arctic Alumina's consistency is engineered for easy application in a thin even layer. During the CPU's initial use, the compound thins out to enhance the filling of the microscopic valleys and ensure the best physical contact between the heatsink and the CPU core. Then the compound thickens slightly over the next 50 to 200 hours of use to its final consistency designed for long-term stability.

10-01-2006, 09:35 PM	#6
Highmark I wanna be Dave Join Date: Jan 2004 Location: Austin Texas Posts: 3,866	120K? Must be a rotary....

10-01-2006, 09:54 PM	#7
Unholy I wanna be Dave Join Date: Mar 2006 Location: One Legend. Posts: 2,134	Great Idea! Just be carefull that you use a high quality, NON-CONDUCTIVE & NON-CAPACITIVE product... or your fix will not work so well. Kevin posted a product that fits that bill, don't think you can use any old thermal paste and it will work with the same results!

10-02-2006, 04:27 PM	#9
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	What about then sticking a heatsink on the back of the servo case?

10-02-2006, 07:59 PM	#11
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	Are you making that up?

10-02-2006, 08:02 PM	#12
666 MODERHATER™ Join Date: Nov 2005 Location: Colorado Posts: 10,939	What did you do to repair the burned up servo? I have 2 5995's like that, but my 5955's never burn up?

10-02-2006, 09:28 PM	#14
JasonInAugusta 06 Super National Champ Join Date: Jun 2004 Location: Stark Industries Bar and Grill Posts: 11,361	A pair of 94359Zs would fix that too! ;) TXT-666, you don't repair them, the FETs are gone. You can send'm to hitec for repair. Heat is the absolute enemy of a semiconductor...

10-03-2006, 10:03 AM	#15
kevinlongisland The Wheels Keep Turning Join Date: Jan 2004 Location: Phoenix, Arizona Posts: 2,831	You can buy this version online if you can't find it locally: http://www.radioshack.com/product/in...entPage=search Arctic Silver® Ceramique Thermal Compound Electrical Insulator: Céramique does not contain any metal or other electrically conductive materials. It is a pure electrical insulator, neither electrically conductive nor capacitive.

07-28-2007, 07:26 PM	#16
Stormin2u I wanna be Dave Join Date: May 2007 Location: Taylors Falls just hanging with the MNRCRC crew. Posts: 7,843	Kevin, That was a great thread I have been looking for a new more powerful servo and I like the Hitec 5995 but I was concerned about it overheating. My Futaba Magnum 2PL has epa so I should be able to cut the 180 degree rotation to something closer to 45 or 50. I'll be ordering one soon TCS of course Thanks Stormin'

Sponsored Links

07-28-2007, 07:40 PM	#17
Kamikaze I wanna be Dave Join Date: Oct 2005 Location: Columbia TN Posts: 6,154	I got a pair of these from Kevin for my super, they are top notch for sure. Just be sure to keep your fingers away from them.........:-(

08-13-2007, 01:37 PM	#19
renoirbud RCC Addict Join Date: May 2006 Location: China Grove, NC Posts: 1,395	hey there How many servos can be treated with each tube of the Radio shack stuff? I might as well do all my robot servos at the same time. Thank you in advance. Rene

08-13-2007, 07:50 PM	#20
kevinlongisland The Wheels Keep Turning Join Date: Jan 2004 Location: Phoenix, Arizona Posts: 2,831	The last time I did one I put the whole tube in there. It filled the entire area inside. I think that will provide the most protection.

RCCrawler Forums

Thread: Hitec 5995tg Robot Servo Fix - Help save your robot servo from overheating