[HELP 8366 Steering Issue

[mathprofdk]

This is a bit of a long shot, but I purchased an 8366 a couple of years ago (you don't want to know the price). Despite being pretty dusty from sitting on a garage shelf, it ran perfectly.

Now it's a couple years later, and the steering is acting up. The motor turns left just fine, but only intermittently turns right. I'm assuming there's a contact in there that's loose or dirty, but I'm not quite knowledgeable enough to diagnose which one.

I was able to open the receiver and I can see all the connections. Everything looks fine visually.

Also, I did have some battery acid leakage, but I only see evidence of that in the battery area. I found another thread about cleaning that off, so I'll do that next 

So, any ideas? I can post pics if that would be helpful. I'm a bit of an electronics novice, so my apologies if this isn't enough detail.

~DK

[TechnicRCRacer]

Just guessing here, maybe some dirt and grime got stuck in the steering unit, motor in the receiver, or joystick box in the remote?

[Bartybum]

Not that I’ll know how to help, but definitely post pics

[syclone]

Had the same issue with electronics in 8675, most probable cases are:

• corrosion in the receiver motherboard
• corrosion in the steering subassembly 
• dirt in the steering subassembly
• corrosion in the remote

A few photos could help identify the problem

[mathprofdk]

Ok, here are the photos I took. One of the remote, and then 3 of the receiver area near the steering motor.

https://photos.app.goo.gl/s4xVPHxfyo8NKrG49

It turns perfectly left, but intermittently to the right. It will often do like a "false start" and turn partly, reset, then turn completely. It seems to work better the more it gets used. Like, if I try to engage it 10 times, it will behave like I've described above the first 3 or 4, then work fine the last 6 or 7.

Edited July 3, 2019 by mathprofdk
Typo

[syclone]

What you described is exactly the same problem I had with the Offroad Challenger. In regards of the photos, I'd recommend to clean whatever that brown material around the wires is, and apply a little of hot glue to protect them. I have no idea what it is, but it definitely had seen better times. 

What worries me more is the rotation sensor, the part you haven't dissasembled (where the transparent cable goes) as it has a brown-ish color and is responsible for the steering return-to-center and angle. Personally I'd check it as it seems to be problem having in mind how clean the motherboard is.

[mathprofdk]

7 hours ago, syclone said:

What you described is exactly the same problem I had with the Offroad Challenger. In regards of the photos, I'd recommend to clean whatever that brown material around the wires is, and apply a little of hot glue to protect them. I have no idea what it is, but it definitely had seen better times. 

[image]

What worries me more is the rotation sensor, the part you haven't dissasembled (where the transparent cable goes) as it has a brown-ish color and is responsible for the steering return-to-center and angle. Personally I'd check it as it seems to be problem having in mind how clean the motherboard is.

OK, I'll take a look. Based on some other sources I've seen, the recommendation was vinegar to clean, then alcohol to clean off any vinegar residue. Does this seem reasonable?

It appears (from my novice research) that the brown material might be rosin remaining from the original soldering. I believe all the joints have it. I'll do some cleaning and get back to you. I'll also try to see if I can do any further disassembly of the rotation sensor. As I wrote earlier, I am an electronics novice, and I'm nervous about doing any damage.

Thanks so much for taking the time to respond. This is a pretty awesome set, so I'm really hoping I can get it back working. I really appreciate the help.

[powerwindows83]

do this at your own risk, but if you pour out a little tub of rubbing alcohol and just dunk the thing (no power sources in it obviously) it will clean out anything thats sitting where it shouldnt. swish it around a little to make sure its thoroughly rinsed out. alcohol evaporates and doesnt leave anything behind so no worries there. you might want to do a quick once-over and make sure theres grease/oil where there should be afterwards, but that should do the trick if the problem is actually on the vehicle side of it :)

[mathprofdk]

Thanks for all the tips everyone. So I've had some luck. I haven't rebuilt the model, but the steering appears to be functioning correctly.

The key ended up being inside the steering component within the remote control. I don't have any pictures, but I had to take apart that component and do a little cleaning. Honestly, it all looks pristine. I used a Qtip in some running alcohol and liberally spread it on the little circuit board inside the steering component. 

One thing to note is that it seems to be pretty sensitive. I'm not sure if it's the alignment on the board or if there was still alcohol, bit it initially was even worse after my first cleaning - turning 180 degrees one way and not at all the other. I didn't change anything, but just positioned the controller again and got it working.

I had it powered up throughout and would periodically check to see if what I had done made a difference. 

Thanks again for the tip. I'm going to build a model using it soon, so hopefully it will continue to work!

[coinoperator]

On 7/2/2019 at 11:28 PM, mathprofdk said:

the photos

Argh
You used Duracell

If it rots like hell then you are using Duracell.

[mathprofdk]

On 7/11/2019 at 3:23 AM, coinoperator said:

Argh
You used Duracell

If it rots like hell then you are using Duracell.

Good to know! I like to use rechargeable ones, but I must have had some alkaline ones in there at some point. Any particular brands you'd recommend if the need arises?

[syclone]

Personally used VARTA before. Only had them rot once - 6 years inside a forgotten toy. Rechargeable-wise, 1.6V Ni-Zn are beasts. Glad to see steering problem has gone away!

PS: Energizer's good too, "that's positivenergy"

Edited July 12, 2019 by syclone

[coinoperator]

On 7/12/2019 at 7:37 PM, mathprofdk said:

particular brands you'd recommend

Energizer claims 10 years leakproof waranty
A lot of electronics guys love GP batteries
Recharchable GP's (Recyco) are really superb (and expensive)