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06-15-2011, 06:13 AM | #1 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| How to tell.....did I kill a HiTec 7950??
OK, I have a 2.2 Bully rig of ~6.7lbs. It's running 3S, dual CC ESC's, CC 10A BEC (was set to 6.5VDC with the 7955, changed to 7.5VDC for the 7950) wired direct to the servo. I ran a 7955TG for months with no problem. Did some steering mods (to get more steering) and added the 7950 @ 6.5VDC. I still needed more steering so went with an Integy long aluminum steering arm (cheap but good for testing, clamping type) and bumped the BEC voltage to 7.5VDC. Ran maybe a pack through it and had weirdness from the servo. It would randomly stop in a position (turned either way, near neutral, just random). If I let it sit, sometimes it would work again, sometimes I needed to kick a front wheel or move forward/reverse to get steering back. It did this tires on or off the ground. At times, I noticed when it stopped, I didn't hear the "hunting/buzz" from the servo. Push the servo arm and it would buzz & work. I double checked the EPA's, made a minor tweak. At one point, I checked the servo temp, it was "warm", but not hot. Figured I fried a CC BEC so put in a new one @ 7.5VDC, same issue. Swapped steering to another channel to test the RX, same issue. I did find new servo arm has a deeper pocket in it, this leads to binding. I removed some material from the arm to get some clearance. While there was a bind because of this, you could still "easily" twist the servo arm. With the arm shaved, it's even easier so I don't consider the bind to be real bad. How do I tell (other than the above) if I fried the servo? Any other ideas? My son is saying that he has read "many people" have fried 7950's when running @7.5VDC, I don't see that anywhere but maybe I missed it. I didn't see anything posted that may indicate anything else to check or "issues" with this servo. Sigh, I picked up another 7950 last night 9comp this weekend) & will deal with HiTec, just want to make sure I don't kill another one. Yes, long post but wanted it complete to limit replies/questions. |
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06-15-2011, 08:14 AM | #2 |
Pebble Pounder Join Date: Jun 2010 Location: Olympia
Posts: 170
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From all of the tests you've done it does indeed sound like the servo has kicked the bucket.
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06-15-2011, 09:54 AM | #3 |
Rock Crawler Join Date: Dec 2010 Location: Beaumont Tx!
Posts: 508
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Mine did same thing and eventually I kept messing with it and it let the magic smoke out. Go ahead and mail it in, it takes about 2 weeks to get it back.
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06-15-2011, 09:58 AM | #4 |
RCC Addict Join Date: Oct 2009 Location: Nanaimo, BC (Vancouver Island)
Posts: 1,153
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Mail it in and since you had to purchase another one to get you by I would ask them to send you back the 7980 just to try out. Can't hurt unless you really like the specs of the 7950 but hey why would you need 2 |
06-15-2011, 11:33 AM | #5 | ||
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Quote:
Quote:
Thanks (sorta....) for the verification. Just wanted to make sure I didn't miss something stupid, thus the looong initial post. | ||
06-17-2011, 07:12 AM | #6 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
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OK, picked up a new 7950 locally, it went in and everything works (although I dropped the BEC voltage to ~7.2VDC). Also emailed HiTec to see what they say. We shall see. |
06-17-2011, 07:59 AM | #7 |
RCC Addict Join Date: Oct 2009 Location: Nanaimo, BC (Vancouver Island)
Posts: 1,153
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You might want to consider getting a hitec hpp-21 programmer, I just bought one for my 7980 and 5955 plus a few buddies run hitecs so it will come in handy in the future. Put that servo into 10% overload protection and according to SCorpionKing it will save that servo from these kinds of issues. Just bought mine for $26 shipped to Canada but seeing how your in the States it may be cheaper yet for you. Check servo city if your interested in it.
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06-17-2011, 09:20 AM | #8 | |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Quote:
I have a LHS that is equal/cheaper than ServoCity, they are ~10 miles from home. The 2nd 7950 I bought was $130.00US out the door ($120 + $10 tax), not a bad price. I believe they are "Power Hobby" in Suffern, NY, but are http://myworld.ebay.com/expresshobby/ online. I will likely keep this updated. | |
06-17-2011, 09:31 AM | #9 |
RCC Addict Join Date: Oct 2009 Location: Nanaimo, BC (Vancouver Island)
Posts: 1,153
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Seems to be on par with rcmart, check them out for super cheap pricing on futaba 4pl(they are updated) and Hitec servos, I was looking at buying the 7980th and was all set to pay the 180 or whatever they go for at horizon, then I jsut found it for $125 + $6 frt and it gets to Canada in 7-10 days marked as a gift. The 7950th is 119 on that site so I say you did just fine bro |
07-13-2011, 06:14 AM | #10 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
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I know HiTec has had the servo since 6/29 (tracked it via USPS) so it should be back soon. The new 7950 has been fine. |
07-13-2011, 07:47 AM | #11 |
I wanna be Dave Join Date: Aug 2004 Location: central VT
Posts: 2,300
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While this thread is up: What does Hitec require you to send in for warrentee repairs? I.E. The original plastic box, proof of purchase, un-molested wiring? Do you need a warrentee confirmation number before shipping it in? I ask, because I have a month old 7954SH that jitters and I cut the wiring harness to solder the power and ground straight to the ESC's battery harness and want to know if I should solder it back together like stock before sending it in? Sorry for the newb question. |
07-13-2011, 08:05 AM | #12 |
RCC Addict Join Date: Dec 2006 Location: Oak Ridge, TN
Posts: 1,141
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Hitec wants all the original packaging that you have left box, paperwork etc... Plus a receipt and the form from their website. They want to test the servo to decide if it's a warranty repair or not so I'm guessing it needs the original plug on it.
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07-13-2011, 09:47 PM | #13 | |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Quote:
Paperwork has my email address & phone # on it. | |
07-15-2011, 02:25 AM | #14 |
no talent hack Join Date: Feb 2007 Location: Redwood City
Posts: 2,479
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as long as you fill out and mail in the service request form you can get through their website you should be fine. i have never had an issue for any reason. i dont think i have ever given a reciept for service with a 50 or 80. all servos are covered for 3 years and neither the 50 or 80 have been out that long
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07-18-2011, 08:51 AM | #15 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Servo returned to me after service.....
OK, I arrived home from a business trip late Saturday and found my servo had returned (no shipping/tracking info from HiTec....it just "showed up".) The work sheet stated, "damaged motor, motor replaced". So, maybe I got a bad one, fecal material occurs at times. My other 7950 is working well at this point. But, I'm still running it within listed voltage limits, not higher. So, we shall see. Thanks to HiTec for covering this as it's not a cheap servo. |
09-17-2011, 06:58 AM | #16 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
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OK, just received our 2 HiTec servos back from the HiTec Doctors... The 7954 had a "damaged amplifier" and a "damaged motor", the whole servo was replaced. The 7950 had a "damaged amplifier" and a "damaged motor", both parts were replaced. Interestingly, the SN's are "next to each other", not sure if it the servo SN or a number assigned to me. I did get an email when they were received, but not when shipped. Total time was 1.5 weeks. |
09-17-2011, 08:23 AM | #17 |
RCC Addict Join Date: May 2008 Location: Chicago/Bloomington
Posts: 1,505
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You're luckier than me, I got a repair estimate for $79 to fix my servo I sent in. I opted not to repair it and I bought a CS-170 (rebadged 5955) for $10 more, new gears, new board, new case, etc. That was four years ago and I'm still using it in my Bully MOA today. |
09-17-2011, 08:34 AM | #18 |
MODERATOR™ Join Date: Jul 2004 Location: Ohio
Posts: 18,928
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I'm curious if the voltage did the damage.
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09-17-2011, 01:06 PM | #19 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| I guess you mean the 7.5 volts? The second one in this thread is the one I had repaired from the 1st post. I believe my son was running his CC BEC at max rated voltage, not 7.5 volts. So HiTec got to see the same servo twice in a couple months. I'm still running my "replacement" I bought. My son has his 7954 back, so I now have a new 7950 "spare", he was running my "repaired" 7950 until we could ship his 7954 back to HiTec. Did you follow all that?? |
09-17-2011, 01:55 PM | #20 |
RCC Addict Join Date: Jul 2009 Location: reelsville
Posts: 1,871
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