Mighty Mule FM500 blew up green circuit board by reversing battery
Joseph Donner
in reverse by accident?
I blew up something on the green Mighty Mule FM500 GTO gate opener circuit
board. Now I have a constant alarm and the gate won't operate.
I have basic soldering skills. I'm pretty sure the same stuff blows up each
time the battery contacts are accidentally reversed.
If you've ever fixed the blown Mighty Mule circuit board, can you tell me
which component is the one that fails?
RickH
Post a schematic.
There might be a protection diode for wrong polarity. A simple
parallel diode protection only protects briefly then the diode blows.
A parallel diode with a series thermistor on the power (or fuse) is
better, the thermistor acts like a blown fuse when it gets hot, then
conducts again when cool. Sometimes a bridge rectifier or series
diodes are used. Start testing parts from the battery terminals going
deeper. Check any thermistors, fuses or diodes first. Hopefully
something in the protection circuit blew and no current got to the
functional circuit.
Joseph Donner
>> If you've ever fixed the blown Mighty Mule FM500 circuit board,
>> which component fails when the battery is hooked up backward?
>
> Post a schematic.
I asked GTO Technical Support but they said they don't have schematics for
the green Mighty Mule FM500 circuit board.
Searching the net, I find this great set of GTO circuit board manuals:
http://www.centralcoastgates.com/gto%20product_manuals.htm
I was hopeful when I saw what appeared to be the perfect link there:
"FM500 Green Board"
However, when I click on that link, unfortunately, I can't read the PDF:
http://www.mightymule.com/PDF/Manuals/FM500-Mighty-Mule-g.pdf
Do you have a better PDF to read this Mighty Mule FM500 (green) circuit
board schematic?
Tony Hwang
You don't have PDF reader?
It's free from Adobe.
Plumber Bob
> > However, when I click on that link, unfortunately, I can't read the PDF:
> >http://www.mightymule.com/PDF/Manuals/FM500-Mighty-Mule-g.pdf
I can't read the PDF either. I think it's corrupted or a newer
version.
It just comes up blank in my web browser. No error. Just blank.
I'm using the latest Adobe Acrobat Reader.
Maybe the file is corrupt or you need a better reader than Acrobat
(foxit perhaps?) to read this PDF wiring diagram?
Tony
I got curious and tried the link. It looks like one hell of a big file,
it was downloading for over a minute when I got scared that it may be a
virus and stopped it.
Marilyn & Bob
news:7512c33f-01de-4a97...@z41g2000yqz.googlegroups.com...
***
Comes up as 43 blank pages on the latest version of FoxIt as well.
--
Peace,
BobJ
Jules
> On Jan 7, 4:40 pm, Tony Hwang <drago...@shaw.ca> wrote:
>> > However, when I click on that link, unfortunately, I can't read the PDF:
>> >http://www.mightymule.com/PDF/Manuals/FM500-Mighty-Mule-g.pdf
>
> I can't read the PDF either. I think it's corrupted or a newer
> version.
I think it's screwed - there seems to be 3 bytes of crap right at the
start of the file, which stops it opening in anything.
Getting rid of those lets me pull out version info (PDF 1.4), creation
date etc. and it shows up as a 43-page document - but nothing I've thrown
it at yet shows anything other than 43 blank pages, so it seems there's
some other corruption in there somewhere still (I don't have any PDF
fixing tools on the systems here).
Joseph Donner
> I got curious and tried the link. It looks like one hell of a big file,
> it was downloading for over a minute when I got scared that it may be a
> virus and stopped it.
I couldn't find a way to read the PDF schematic and nobody knew where there
was a schematic for the GTO gate opener (green) was so I had to give up on
trying to fix it after I accidentally reversed the 12v battery (you'd think
they would have protection circuitry built in for that).
So to give an update to my friends out there ... I just now ordered the
Sears Item #00977051000 Mighty Mule FM500 Model R4211 Replacement Control
Board (blue) for 322 dollars ($280 + $28 tax + $14 shipping).
http://www.sears.com/shc/s/p_10153_12605_00977051000P?vName=Tools&psid=FROOGLE01&sName=Gate+Openers+&cName=GarageDoorOpeners&sid=IDx20070921x00003a
Thanks for your help. I also picked up a few more of the gadgets that go
with the gates, so it will be interesting to put it all together when it
arrives.
They say to bury the 16 gauge multi-stranded two-wire low voltage wire. I
was thinking of putting a PVC conduit in since animals chewing on the wires
started this whole mess in the first place.
Do you know what size PVC conduit & how deep to bury low-voltage wires in?
RosemontCrest
> So to give an update to my friends out there ... I just now ordered the
> Sears Item #00977051000 Mighty Mule FM500 Model R4211 Replacement Control
> Board (blue) for 322 dollars ($280 + $28 tax + $14 shipping).
Did you notice the rebate offer on that site?
> They say to bury the 16 gauge multi-stranded two-wire low voltage wire. I
> was thinking of putting a PVC conduit in since animals chewing on the wires
> started this whole mess in the first place.
>
> Do you know what size PVC conduit & how deep to bury low-voltage wires in?
First, check your local codes.
If your existing wire is type UF intended for direct burial, many
jurisdictions do not allow the use of such cable within a conduit. For
use within a conduit, type TW (THWN or THHN/THWN) wire is usually
required.
The last time I checked, 1/2" PVC conduit can house up to five 12-
gauge wires or six 14-gauge wires. Larger conduit makes it easier to
pull the wires and add new ones later.
Remember to get a spool of nylon string when you get the conduit.
Good luck.
Tony Hwang
For curiousity I stuck it out and downloaded whole 43 pages.
All pages are blank.
PeterD
How many wires? Usually 1/2" PVC works OK. Deep: about 16 inches, if
low voltage circuit in conduit. Deeper if possible if no conduit.
Jim Yanik
news:m6qjk5pj2hr5fb9ml...@4ax.com:
you want to bury pipes and wiring below the frost line in your
area. Otherwise ground heave will break them.
--
Jim Yanik
jyanik
at
localnet
dot com
Joseph Donner
> Did you notice the rebate offer on that site?
Yikes. I will call them back to get the rebate! Thanks.
> If your existing wire is type UF intended for direct burial, many
> jurisdictions do not allow the use of such cable within a conduit. For
> use within a conduit, type TW (THWN or THHN/THWN) wire is usually
> required.
Interesting. I didn't realize the wire had to be different if it went
inside the conduit. Now it makes a bigger difference which way I go,
conduit or not.
> Remember to get a spool of nylon string when you get the conduit.
Is this for pulling the wire through the conduit?
Joseph Donner
>>Do you know what size PVC conduit & how deep to bury low-voltage wires in?
>
> How many wires? Usually 1/2" PVC works OK. Deep: about 16 inches, if
> low voltage circuit in conduit. Deeper if possible if no conduit.
I will probably put two sets of double-stranded 16AWG wire in the conduit.
One set will be for the 18VAC power and the other set for the intercom.
16 inches seems pretty deep. I was thinking more like half that (there is
no frost here).
Joseph Donner
> you want to bury pipes and wiring below the frost line in your
> area. Otherwise ground heave will break them.
I don't think there is a frost line in San Jose California?
Is there a web site I can look this up?
Joseph Donner
> For curiousity I stuck it out and downloaded whole 43 pages.
> All pages are blank.
Thanks for checking. I thought it was just me. It would be nice to find a
schematic for the Mighty Mule FM500 circuit board (green).
RosemontCrest
Yes. When you install the conduit, you can either include the string
and wires when you glue together the conduit, or you can just include
the string. If the latter, when pulling the wires, add another length
of string to enable pulling additional wire in the future. Always keep
a length of string in the conduit.
PeterD
Leave it in the conduit, when you pull your wires through. Then at
some point in the future when you need another wire in there (it
always happens) it is easier to pull that new wire in the conduit.
PeterD
wrote:
I've not had that problem here in NH, but if you can, it cannot hurt.
Most plastic is flexible enough to withstand the stress of frost.
PeterD
YOu want it below where any landscaping/gardening/maintenance is
likely to hit it. That's the 16 inches.
RosemontCrest
> On Sun, 10 Jan 2010 14:00:42 -0800, Joseph Donner
>
> >On Sat, 9 Jan 2010 19:36:08 -0800 (PST), RosemontCrest wrote:
>
> >> Remember to get a spool of nylon string when you get the conduit.
>
> >Is this for pulling the wire through the conduit?
>
> Leave it in the conduit, when you pull your wires through. Then at
> some point in the future when you need another wire in there (it
> always happens) it is easier to pull that new wire in the conduit.
Again, pull a new length of string when adding new wires. Always keep
RosemontCrest
> On Sun, 10 Jan 2010 14:02:00 -0800, Joseph Donner
>
Exactly. It's not just the concern of frost damage. I would bury it at
least 24".
HP maint. Tech
yes.. there is a diode that protect the board. Use your DVM on diode mode
check it the diode string ( polarity sensitive if you haven't checked Diodes
before). These are all surface mount componets so a small soldering iron is
all that is needed. Too large of a soldering iron you could lift the trace. I
have a Blue Board and did the same thing connecting my gate to the battery in
the dark and replaced the one diode that open up. Cheap fix few cents vs $250
for new board.
--
for full context, visit https://www.homeownershub.com/maintenance/mighty-mule-fm500-blew-up-green-circuit-board-by-reversing-b-416815-.htm
Joseph Donner
> replying to Joseph Donner, HP maint. Tech wrote:
> yes.. there is a diode that protect the board. Use your DVM on diode mode
> check it the diode string ( polarity sensitive if you haven't checked Diodes
> before). These are all surface mount componets so a small soldering iron is
> all that is needed. Too large of a soldering iron you could lift the trace. I
> have a Blue Board and did the same thing connecting my gate to the battery in
> the dark and replaced the one diode that open up. Cheap fix few cents vs $250
> for new board.