Does anyone know where I can get a circuit board at a decent price for my
Millermatic 185? It is the one for the wire feed control and the P.N. is
171986. I contacted the local supplier and they want $226. for it. I don't
know if this is the "normal" price for this or they are just doubling it
like most places do. I would also be interested in a repaired board if I can
can you use a soldering iron?
Can you use a multimeter?
If yes, how about having a crack at getting your machine
up and running again?
There are a lot of helpfull people on this group, with a combined
group effort we could probably help you fix that unit of yours.
Is this the hook up diagram? page 24.
I am assuming that you press the trigger on the gun and
the wire speed motor does not run. Is that correct?
If you are interested in having a go at fixing the board
can you take a photo of it so we can all see it.
How do you know the board is the cause of the trouble?
Are you just guessing?
Have you substituted a known good board for yours and
proved it is dud for sure?
Sorry I had to ask.
Over to you Doug,
I agree with John. How did you determine that the board is bad? I had a
problem with my 185 and it was in the switch wiring in the gun.
The board regulates dc voltage to the drive motor. Are you sure the motor is
good? If it is the board, do you know why it failed?
The circuit is pretty simple and is repairable.
with you having the same machine as Doug and maybe
Brad, with his connections in the trade, can get a copy
of the circuit diagram of the control board, fault finding
could now be pretty easy.
Is there any chance of a circuit diagram from you Brad?
Just for interest Tom, can you remember what is on that
board? Don't go opening up your machine just yet.
Doug may not come back.
Where are you Doug? You have got me interested.
I'm sorry about the slow response, but I'm usually busy with other things on
the weekends and of course I have to work on Monday.
Now to fill you in on like Paul Harvey would say "The rest of the story"
A couple of weeks ago we got a lightning strike close to the house and barn,
knocked my cordless phone off the charger and blew the modem in the computer
(yes I have a surge protector on it), also took out two breakers in the
shop. The first time I went to use the wire welder the wire runs out at what
seems like a speed faster than the fastest setting. So going through the
electrical diagram they just show the connector going to the circuit board.
I checked the resistance through the pot. for the speed control and it
checked out alright. The motor and gun switch works, because it obviously
feeds too fast. I popped the circuit board out and found two blown
capacitors, and maybe a third one. I went to the local Radio Shack and the
guy in there was of very little help. He told me I would need to know the
value of the old ones so he could give me a replacement. Unfortunately with
the old ones being burnt out I can't get a value.
I took a picture of the board, I don't know how well you will be able to see
it, but it is capacitor C5, C9, & C10 that are in question. The C9 capacitor
has the top blown right off of it and the C5 is blown out the side, the C10
looks as though it got hot so I was going to replace it too.
Now we're getting somewhere. Can you post a link to a web site where the
photo is? Or email it to me. You may have some other parts that are failed.
I know that they feed 24 volts ac to the board and it is rectified to dc. If
one or more of the diodes shorted, that would place ac on the caps. It could
explane the burned caps.
If necessary, I could look at the board in my 185. Let's see if someone else
comes up with a schematic.
thanks for the e-mailed picture. I will talk to you on the group..
Tom can help you out here with the value of the capacitors. You
will probably have to wait until he gets some time at the week end
also. In the mean time, buy some solder wick and maybe one of
those tools called a "solder pullit" and remove the known dud
Get your self into a mind set: say to yourself,
"I am going to fix this board. I am not going to pay $226. I will
check every single component if I have to."
Start with the easy stuff. Lift one end of the resistors and check
each one with the ohm meter range of your multimeter. Do the
same with the diodes. Get rough if you like and snip the component
lead and blob it with solder later. Don't struggle to remove a
component that costs next to nothing and end up mangling the
tracks. Protect the tracks before cheap parts. Cheap stuff can
be replaced later when it is working. Lets just find the duds for
Remove the transistors and check them also with your ohm meter.
I like to use an analogue type multimeter with a pointer not a digital
ohm meter for checking the transistors junctions.
The remaining capacitors, remove them also and check them
for leakage. Digital multimeters are becoming so cheap these
days, some even have a capacitor measuring function.
See if you can borrow a multimeter that checks capacitors also.
If you can't get one of these capacitor checking DMMs, then just
reverse the leads of your analogue ohm meter when testing the
capacitors for leakage and you will see a small meter movement
as the capacitor charges.
If there are a few welding stores near you, call in and ask for
the diagram for the board. You never know your luck, some
will tell you to bugger off and others may give you a copy.
Ask to speak to the repair man if possible not the boss or
counter attendant. A technical guy is more likely to help you.
Have a go Doug and have some fun,
what do you mean lack of responses? We have been
waiting to hear from you.
We are all here ready to help you fix the board,
where have you been?
Tom has the same millermatic 185 mig welder.
Did you not see his post offering to look up the value
of the damaged capacitors on your control board?
How did you go doing individual component checks
on the board? Did you find any dud semiconductors?
Over to you.
I guess maybe I have not keep up with everything, but I did not see his
post. I been watching for a reply but did not see one. Anyway I know I need
three capacitors, I really don't want to unsolder everything off the board
just to check the resistance. If there is anyone that would be willing to do
this for me? I would something for the time and effort. I am thinking of
getting a new one and repairing this one in case this would happen again.
These things always seem to happen when you need it the most. Thanks for
your reply I wish I could find Tom's but I don't see it.
here is a copy of Tom's post
Now we're getting somewhere. Can you post a link to
a web site where the photo is? Or email it to me. You
may have some other parts that are failed.
I know that they feed 24 volts ac to the board and it is
rectified to dc. If one or more of the diodes shorted, that
would place ac on the caps. It could explane the
If necessary, I could look at the board in my 185. Let's
see if someone else comes up with a schematic.
have you been to any welder repair shops and asked for
a copy of the schematic? If they don't want to give you
a copy then plead your case and ask for the values of
the destroyed capacitors. They should at least do that.
Write to Miller's managing director for the values of the
capacitors if necessary, if their after sales service people
will not help you out with the values or a schematic.
Tom is here and willing to help you with the values,
send him the picture and the reference numbers if
you have no luck with Miller or their repair agents.
If you get lucky with a schematic with component values
and the welder repair people only wish to do board
replacement repairs and not do component level repairs,
you could take your welder to your local TV repair shop
or a Ham radio electronics man and they might be
willing to fix it for you. With a circuit diagram any
electronics man will be able to fix the board.
This $226 replacement board type of repair is
totally wrong. I wonder if someone has a service
exchange type of business. You give them your
dud board and for $50 or so you get a used but
repaired board in return.
Getting back to the dud board. At the moment it
is dud and worthless so what have you got to loose
by ripping into it. Nothing.
OK you don't like the idea of carefully removing
every component for checking, perhaps you don't
have the skills. So cut tracks to isolate components
for checking. Use a sharp stanley knife/box cutter.
Make one neat little cut, a tiny nick, to isolate a
resistor, capacitor or diode. Make two track cuts to
isolate a three legged transistor. The cut tracks can
be made good by soldering a little fine strand of wire
across the narrow cut.
Get yourself in the right frame of mind, sit down at the
kitchen table with desk lamp, magnifying glass,
multimeter, modelling knife/box cutter and get started.
Two to three hours and its done. Once you find the dud
parts we can then start looking for suitable replacements.
Hoe into it Doug, you can do it. You have nothing to
loose and everything to gain.
I sent you an email.
I will try to help you get this working. I have a working 185 to compare it
to and most of the parts on the board. As long as the board track is good
and the board is in tact, it should be repairable.
Contact Innovat. They rebuild circuit boards for most welders and industrial
Call 276-783-9771, at least this is the last # I have for them.They are in
Rebuilds are typically 1/3 the cost of new.