Mighty Mule 502 Solved (maybe)

[Soundguy]

I have used apollo equipment at our work sites in the past. no issues till dump trucks run thru gates or lightning strikes.

Concerning MM openers.

In the last 20 years I have had 4 of them. 1 honestly died due to no fault of it's own, wife hit it with her truck. 2 had control boards die, one had a motor die. This last one a week ago had the nut in the arm strip out, however the motor and threaded rod looked fine.

I did some surgery, and removed it's operational board and put that board into one of the 2 units I had as spare parts that were about 1-2 ys old that had boards die.

Worked out good. I see a slight difference in the boards where the solar ties in, but it made a good swap. If I can get 5 years out of this one I'll be happy.

 

[flyerdan]

When I worked for the fence company, I was always pulling those out of the garbage and taking them home, probably have three dozen or so. They are pretty rinky-dink, and with a motor the size of a D battery you can't expect much. But they are easy to work on and lend themselves to repurposing.

 

[Soundguy]

Out of all of the units I had go bad over the years, only one was a motor failure. I'm fairly impressed with the motors. less impressed with the board stability.

 

[TractorGuy]

I have a 362D system that the slave opener intermittently operates at half the speed of the main. Emailed MM within a month of purchase and they didn't reply for a couple of weeks. After they replied I tried all their suggestions and nothing worked so I emailed them again and never heard back. I even met a guy in their finance division that said he would ask the tech department and he never heard back from them. Pretty bad when they ignore their own employees.

Other than what they suggested I never took the time to look at it further but I imagine it is getting low voltage to the slave opener. The fact that it's intermittent would suggest it isn't in the long length of wire but more than likely in the control board relays. A reputable company would get right back to you and offer to replace the board on a system that is practically new and under warranty.

I even posted a link to this video on one of their advertising videos and they never replied or removed the link.

slow gate opener - YouTube

I am still putting up with my 362D system. It has not failed to work yet but the slave gate operates at half speed about 70% of the time. If I ever get a "round tuit" I will look into replacing the slave relays on the board as I assume that is the problem.

I had two FM 350 systems on a single gate prior to the double gate system. The first got burned up by a lightning strike and I still have the operator laying around from that one. Since I live in the GTO area I took the first unit in for repair but was quoted 2/3 the price of a new unit so I just went to TS and bought a whole new one. I was able to recover $175 on that by selling on CL when I went double gate.

 

[joefromga]

I think the stopping and 5 times beeping is the Rev counter out of sync. You may want to check it because if it's not reporting the counts it will stop and the gate thinks it's not moving. This has happened to mine before because if wear on the plastic housing letting too much flex on a heavy gate cause a delay in actual arm movement. I replaced the counter sensor and the housing and its been good since.

These gates aren't super heavy-duty so when they go on a really good sale I'll just buy another arm for backup.

I have called tech support, though and someone answered and guided me through some tests.

I have 2 single gates one which was installed with the old board at least 10 years ago so I've been through the lightning, breaking, new boards, arms, etc.

 

[GabeLogan]

After my second FM502 quit I am never buying another Mighty Mule product as they just don't last and troubleshooting is a nightmare. Any recommendations on other brands to use or avoid? My actuator arm wires are installed in conduit in our rock pillars which I would prefer to not have to pull and replace...any other brands out there that would use the same wires as the FM502?

Y'all may want to check out Ghost Controls Operators and see their Amazon reviews from other user. They offer lifetime warranty on motor and gear box. You can always 'test' call their support line and see how responsive they are before purchasing their product. Their arms have 4-wires vs 7-wires on Mighty Mule so I don't think directly but it may worth a try to wire-nuts them and water proof the connection points. Call their support line, they may be able to give you better recommendation. It's a good test call anyway, right? If they support you without you owning the product, they will likely to support you when you own one.

 

[gckc]

CappyD I have an FM502 and I wanted to try and find a schematic to any Mighty Mule controller even an older model like the MM202 you mentioned. The link is no longer active.
Could you possibly post the schematics again with an active link?
Thanks

 

[Bill J]

I also had the same problem as cappyD and Cartman with my Mighty Mule 502. I considered the tip from Cartman and ordered five Goodsky RWH-SH-112D 12 VDC relays on ebay. I replaced the four relays adjacent to the Master and Slave terminals. It fixed the problem.
I also wasn't a member of this forum and found this thread in a search for my gate opener problem. I wanted pass on my experience and thank Cartman.

 

[Jamespmcb]

Fm502. 4 beeps. Slave gate moves 2 inches. Swapped out rev counter. Batteries at 13.5. Still not working. I like the idea of disconnecting the slave wires then hooking red and black only to master. Does this work any ideas.

 

[Jamespmcb]

This is what I've been working on for the past month or so. If you have ever searched for help with your Mighty Mule you probably know it's useless. There are some good troubleshooting guides out there but if your problem doesn't fit exactly in to a certain category then you are out of luck. I would get so close to a diagnosis using a guide but right at the end everything would fall apart. Usually my readings would be correct but the troubleshooting guide didn't elaborate about what to do in that case. Or it would say something like "If the voltage is between 12.5 and 14.5 the arm is good. Replace the board". I was usually left wondering why not fix the board? Or atleast give me one (or a few) things to test on the board. A new board costs over $230.00 so I'd like to be 100% sure there isn't a bad relay or something else I could fix or someone else fix. Anyway, here's my experience with the gate opener. Maybe some other person will gain something from it. Even if they learn what NOT to do.

After only a few months of having a great worry-free gate opener it bit the dust here recently. My first little issue was about 6 months ago with the slave arm limit switch. Not a big deal to remove it, clean and adjust the little spring inside of the switch.
During that time of researching gate openers I seen where a lot of people had problems with the control board. I was always careful when I had to work directly with the control board. I added a few accessories and everything was fine for about 6 months.
A month or so ago the slave arm started stopping mid-cycle for what seemed to be no reason. Soon after it started that issue it completely stopped working. Since I already had to work on the limit switch I was very familiar with the wiring for the operator arms. I did the usual troubleshooting. I swapped master with slave terminals, swapped rev counter boards, I even connected the slave motor directly to the battery. Everything checked out good. I could not find anything wrong with connections, voltage, rev counter boards, or stall force.
The only reasonable conclusion I had was something in the control board was bad.
Most normal people would just replace the control board and bypass the hours (days) of poking around with a multimeter without knowing anything about control boards. It was impossible to find schematics for the R4211 blue board anywhere on the internet. I was able to find the schematics for an older type Mighty Mule which did help me a lot.
Since I knew exactly nothing about diodes, capacitors, or resistors I couldn't definetively point to the cause of my problems. I was basically confirming voltage was present at different points. When I did think I found a problem I had no way of knowing what the correct reading should be. So I was unable to confirm any component was bad. I gave up on that after a while. That's when I came up with an idea that I never did see on the internet or anywhere else. Here goes...

So here are my symptoms and here is what I did to "fix" it.
With both arms connected in their proper terminals I push the remote and nothing moves. I can hear a click sound (relay?) and the yellow status light flashes 5 times + 1 second pause, then flashes 5 times + 1 second pause. It will continue to flash until I turn the control board off and back on.


******** It may also be giving an audible alarm of 5 beeps as well. I don't know for sure because I removed the speaker. It was very loud and CONSTANT at times.********


If I leave everything connected nothing moves. Doesn't even try. But if I remove the slave arm orange wire or green wire from the control board the master arm works fine. When I swapped master/slave terminals the exact same thing happens. So I know for sure 100% that the issue is in the control board (right??).
After probing and testing and giving up I finally tried this.
I disconnected all of the slave wires from the control board. I twisted the red and black motor wires from the slave arm to the master arm red and black wires. (Red to red and black to black)
After twisting them very tightly and carefully attatching them to the master terminals on the control board everything is back running great. I only had to adjust the slave arm closing distance manually by screwing the tube a little. Both arms open at the same exact time and stop at the exact same time.
As far as I know it seems to be safe to do this. Nothing seemed strained or weak and it sounds normal too.
There are a lot more details to this.
I've learned quite a bit about my gate opener over the past month so if I can help anyone just ask. I'm still not an electronics expert but if I can help just let me know.

********* If you know I am damaging something or if it's not a good idea to connect the slave motor wires to the master motor wires please let me know********

I did the same as you, disconnected all slave wires hooked red and red black and black to master, gates open and close but I cannot get the slave to stop same as master. I've screwed the arm in and out to try and set the stop the same. It just wants to go to far open