Let The Smoke Out Of My 5955

[Ced RC]

I recently put together my first serious super class rig and it has been nothing but headaches with breakage and today I let the smoke out of my rear steering servo, HiTec 5955TG. I'm not sure what to think, I have my CC BEC set at 6.5 volts, and I wasn't even beating on my rig, probably ran it for about 15 minutes, and while the rig was sitting still for a minute, while I was making some radio adjustments I notice a lot of smoke coming from the servo, melted the cover on the backside, opened it up and found a completely melted chip on the little printed circuit board? I have had good luck with my other 5955's but now I'm considering a switch, maybe the JR8711? or maybe something 1/4 scale?

Has anyone else had a 5955 melt down after very little use? My servo which failed probably seen about an hour worth of runtime total?

[SVEN]

Definitely couldn't go wrong with a JR 8711, but first check your steering setup to make sure there's no binding. The 5955's are a bit finicky in that respect. If you can hear it whining, then it is trying to center itself. Meaning it is getting hot, even while sitting still. You never want to let a 5955 stay in a bind for very long, because they do get hot quick.

I think the new 5990's have thermal protection. They will shut down before they let out the smoke.

[tjb]

Just did he same to mine last week......8711 is next on purchase list

[Nova's Ark]

I know exactly how you feel and totally feel your pain. I have a brand new pimp cane Super I am yet to run. The entire rig is built, but it burned up both Hitec 5955 TG's servos in minutes.

Send your servos back to Hitec. They are excellent with customer service and warranty. The new 7955 TG have over load protection, but the 5955 do not. My Super will not run until I get it figured out why they burned up in the first place. Extremely disappointed to have an awesome Super just sitting:-(.

[Scattman]

The 7955TG has overload protection but you need the programmer to turn it on. :-( Default is off.

[Ced RC]

Thanks for all the replies

SVEN, my steering setup is all good, but after reading what you say about the servo making the whining noise, seeking center, you got me thinking, when I'm running a course (practice or comp) it seems that my servos are almost always whining, and they do get hot, but with my 2.2 it hasn't been a problem (I'm running a 5955 on my 2.2 also) but with my Super I have been watching, paying more attention to the steering servos, cause I noticed they were getting much hotter than my 2.2, the larger wheels and tires sure make a difference, kinda makes me want to run 1/4 scale servos on my Super.....

tjb, Nova's Ark: damn the luck, I will be checking out HiTec for repair, for sure, thanks Nova

I'm anxious to check out the 7955 also.

Carnage:

[toy4crawlin]

Never a problem with mine

Instead of another servo
WHY Not call Servo city and ask them for a 20lb (power) actuator under 3" long ????
Time to DITCH the Old School servos and go Mini Actuator

Folks the only way to speed up the production of these is to call and ask them.

[Ced RC]

Originally Posted by toy4crawlin

Never a problem with mine

Instead of another servo
WHY Not call Servo city and ask them for a 20lb (power) actuator under 3" long ????
Time to DITCH the Old School servos and go Mini Actuator

Folks the only way to speed up the production of these is to call and ask them.

Something like this?:

http://www.servocity.com/html/heavy_...ctuators_.html

[Mnster]

Arn't the Hitecs only rated for 6.0 volts? I have mine set at 6.2 and noticed it is sort of glitchy wierd at times. I've been rolling on the same 5955tg's for the past 2 years no major failures. Just recently though one of mine has gotten weak and I have to send it in. Kind of past the warrenty though. Without doubt they are the most tough servos I have ever owned.

[Rockcrawler]

All of the 5995 servos that I have seen that burned up were all this same way. I know a few people that run them at 7.5. I run mine at 6 and have not had any problems yet. I believe that Jason or 666 did a write up somewhere on using a different lube in the back of the case that would not let it get so hot.........

[Rockcrawler]

Found it!

It was Kevin that did the mod......

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

[Rckcrwlr]

First off...make sure you do not put the thermal paste in the servo...they will refuse warranty repair. If you feel the need to do anything...use the thermal tape...that way you can pull it off before sending it in. But that process is mainly used to transfer heat from the board to a metal surface to dissipate. This process only sends the heat to the plastic which will in turn insulate the heat or melt the case.

Sounds like your problem is with the deadband. Deadband is the setting the tells the servo how precise you want it to hold center. It is defaulted at 2 which means it is dead on. That is why you hear the noises when it is just sitting there. It is fighting to center the servo.

If you go by the programmer HFP-20 you will be able to open that up to about 8. In our comps it is not so important to be locked on.

The 79XX servos now have the failsafe that will have them shut down before the melt. It definitely saves you from having a downed rig.

These servos are great as long as you keep them cool.

Adjust the deadband and make sure your endpoints are set to just under them screaming...

Good Luck

[Master Basher]

I watched a dude fry his 5955TG at a comp the other day. It was sad.:-(

[Ced RC]

Originally Posted by Mnster

Arn't the Hitecs only rated for 6.0 volts? I have mine set at 6.2 and noticed it is sort of glitchy wierd at times.

I've read where a lot of people run theirs at much higher voltage, like 7, or 7.5 with no problems, I didn't want to push my luck but the extra half volt seemed to make a noticeable improvement.

Originally Posted by Rockcrawler

All of the 5995 servos that I have seen that burned up were all this same way. I know a few people that run them at 7.5.

I've seen at least several people say they run theirs at 7.5 volts with no problems, I think that might be pushing it though.

Originally Posted by Rckcrwlr

First off...make sure you do not put the thermal paste in the servo...they will refuse warranty repair. If you feel the need to do anything...use the thermal tape...that way you can pull it off before sending it in. But that process is mainly used to transfer heat from the board to a metal surface to dissipate. This process only sends the heat to the plastic which will in turn insulate the heat or melt the case.

Sounds like your problem is with the deadband. Deadband is the setting the tells the servo how precise you want it to hold center. It is defaulted at 2 which means it is dead on. That is why you hear the noises when it is just sitting there. It is fighting to center the servo.

If you go by the programmer HFP-20 you will be able to open that up to about 8. In our comps it is not so important to be locked on.

The 79XX servos now have the failsafe that will have them shut down before the melt. It definitely saves you from having a downed rig.

These servos are great as long as you keep them cool.

Adjust the deadband and make sure your endpoints are set to just under them screaming...

Good Luck

Sucks, I tried the thermal paste trick (not completely understanding how it will help as my experience with PC's shows that the heat would need to be transfered to some sort of heat sink?) but regardless I will try to remove the thermal paste prior to sending it in to HiTec.

Opening up the deadband sounds like a great solution though, makes perfect sense. I know guys who use the 5955 in their large planes and their deadband would need to be very precise but for crawling purposes I wouldn't mind if the servo didn't return to exactly zero, I will look into purchasing a programmer if I stick with HiTec servos.

Thanks guys

[Mnster]

Yeah the 5955tg's are rated for 6.0

The 5995tg's are rated at 7.2

When you search for the issue you see a lot of people getting both servos confussed.

[Rckcrwlr]

I have tested the 5955's at up to 7.3v with no problems...in fact there seems to run cooler at that level.

The thinking is that there is more power so less strain.

It is not recommended by Hitec to run over 6v, though.