industrial sewing machine mainboard/powerboard issue

[tttttthomas]

this is probably a first here... i know alot of you guys(and gals) are knowledgeable about pc and display systems, but what about industrial sewing machine control/mainboards?

i make clothes for a living (all be it not a very well payed living at the moment!) - and use a 'computer controlled' industrial sewing machine to do so.

the machine is a brother db2-b737 with a c-10 control unit.



for those who don't know too much about how this type of machine works, basicly the machine 'head' is purely mechanical, and works the same as any other sewing machine, but, is controlled by the computer box that sits under the motor (under the table) by imputting settings to the console mounted on top of the machine head.
the machine is not a robotic, the computer controller simply allows you to programme how many times to back stitch, or to stitch a certain amount of times before queing you to change direction (for accurately sewing lables etc). - it stil works with a presser foot and is much like any other machine.

the machines 'self lubricate' via a large oil reservoir beneath the machine head, which is pumped up into the machines body, but obviously is sealed from the computer box etc.

this machine also has a solenoid which powers a thread trimmer at the end of your stitch line if programmed.


- brief lesson over - now on with the problem;

last week, suddenly the machine started to produce smoke from the underside of the machine head around the oil tray. i immediately switched the machine off and lifted the head to get rid of all the smoke so i could try to find the problem - a smoking, burnt out thread trimming solenoid.

i found two pins stuck in the oil pumps filter so came to the conclusion that the pump managed to block (due to debrees/pins in the oil tray) which resulted in inadequate cooling and ultimately burning out of the solenoid.

after giving the machine and oil tray a thurough clean, i powered the machine back on and set the solenoid not to be engaged.

the machine worked fine, until today when i tried to turn it on (and it refused!).

the control unit at the top is recieving power, but the machine is unresponsive when using the foot pedal.

obviously this lead me to believe there was some sort of fault in the control box, so i opened it up to see if i could see anything obvious, and the bloody thing was full of oil!

from a bit of poking around, i discovered that the solenoid itself had developed a crack, and the oil was moving from the correct areas into the solenoid body and onto the electrical line down to the control box where it was simply dumping it all over the mainboard and powerboard.


this connection housed the pins for the solenoids power cable, and was the main vent for the torrent of oil heading for the mobo.


this was the state of the motherboard, you can see a nice coating of oil over almost every part of the board.

i imagine this oil caused a short which was stopping the machine powering up, so i carefully dabbed away what i could, then used electro contact cleaner to wash away any excess.

the boards and connections seem in good shape now, but on putting the machine back together, i had no luck in getting it to respond. - i have also removed the pins for the solenoid from the main board, so no more oil could be dumped etc.



i imagine you guys havent dealt with sewing machine control's often (or perhaps ever) but im sure you could give me an idea of where to go next in my quest to fix this baby...

i mean, as a control unit, the unit should share similarities with other units for other types of tools/computers etc.

i really dont know where to start with it, since i am not an electrician, just a natural born tinkerer - who simply cant afford to replace the whole machine right now.

any ideas which parts are most likely to have shorted? i wouldnt even know which parts to begin to think of replacing to be honest and you guys are definately more up to speed than i!


will be super greatful to anyone can help, and ill send a little thankyou package to anyone who can crack it!

thanks!

thomas

[PCBONEZ]

Re: industrial sewing machine mainboard/powerboard issue

If there is oil all over it the WHOLE thing is shorted.
You have to clean up the oil before you do anything else.
- Do not give it power again until you do this.
[It's going to sound scary but this is how it's done.]
.
First get your hands on [probably a couple] large bottles of 91% isopropyl [rubbing alcohol] and get a med or large spray bottle to put some in. [Walmart here has it in 32 Oz bottles.] Looks like there's a lot of boards in there so I'd get two.
- Will need this later on.

Pull the boards and remove any batteries.

Spray them down [heavily] with some degreaser type household cleaner. Mean Green works best [some Dollar store chains have it] Simple Green works okay. Fantastic/409 not so much [just okay] but better than nothing.
DON'T want something with Clorox/bleach in it.
- Make sure you direct streams of spray under the chips and other parts and right into the connectors. The oil will try to hang there and not move without the force of the spray to push it out.

Next wash them in the sink like doing dishes.
Use hot soapy water [dish washing liquid, I like Dawn] and a little heavy on the soap.
Raise them up and down rapidly through the water to get some flushing affect on the PCB .
[Some people just use the dishwasher. That actually works too but don't lay them flat.]

Now rinse thoroughly with HOT water from the tap. [Even if you used a dishwasher.]
Again, use the force of the water drive the soap out of all the nooks crannies.

[With lots of ventilation - if you can do this outdoors.]
Spray them down heavily [as in rinse] again but this time with the isopropyl. - And again direct the spray under everything. The idea is to flush any residuals [soap, oil, water] out from under things and off the edge.
Isopropyl scavanges [absorbes] water and carries it away when it evaporates. It also evaporates fast and leaves no conductive residue. [BTW: I said 91% because it's only 9% water. The 71% is already 29% water so it doesn't scavenge as well. It will still work, you'll just need more.]

Now you need to dry them completely.
I hang them with wire hooks [made from jumbo paper clips or coat hanger] in the sun on the back patio.
If you can't do that hang them from a shower curtain rail or similar and set up a fan to keep the air moving around. If you can make it warm in there that helps too. Also hitting any connector sockets with a hair dryer [low air flow areas] wouldn't hurt but do get things too hot.
- Dry time can vary a lot with temp, humidity and air-flow. In Phoenix in the summer in the sun drying only takes 10 minutes. It's dry and over 110F here usually this time of year. When I was up in Washington and had to do it inside it took a whole day with a fan and a heater in the room and that's with occasional assists with a hair dryer.

While they are drying clean out the cabinet [circuit boxes].
Same basic idea but you don't need the isopropyl unless you just want to speed up the drying.

with some degrease like cleaner. Mean Green works best [some Dollar store chains have it] Simple Green works okay. Fantastic/409 not so much but better than nothing.

After all that put it back together and see if it works.
Now is when we can safely find out if something fried in there without frying something else too.
.

[b700029]

Re: industrial sewing machine mainboard/powerboard issue

Isn't oil usually non-conductive?

HV transformers are filled with it.

[PCBONEZ]

Re: industrial sewing machine mainboard/powerboard issue

Isn't oil usually non-conductive?

HV transformers are filled with it.

Usually - No.
.
In other applications it's actually used as an electrolyte.
Even in capacitors.
.

[Longbow]

Re: industrial sewing machine mainboard/powerboard issue

Sewing machines use a refined mineral oil called white oil for lubrication. Not sure if the same stuff is used in the sumps of industrial machines. However, mineral oil is non-conductive. If, however, the oil is full of metal particles and has not been changed for some time, then I suppose its not the greatest thing to soak your microprocessors in. Odd that a pump problem would dump oil all over the control electronics. Bad show for those engineers.

[PCBONEZ]

Re: industrial sewing machine mainboard/powerboard issue

Not to mention additives.
-
Too dangerous to say it's non-conductive when it's the person's livelihood.
-
Besides which, no telling what the oil or additives will do to the PCB material and/or IC chip casings, nylon connectors or wire insulation.
-
It would also be a major dust magnet on a PCB.
-
Just best to get it off.
-

[tttttthomas]

Re: industrial sewing machine mainboard/powerboard issue

thank you so much for the posts!

PCBONEZ - thanks so much for the detailed post. i had tried to clean it by dabbing and a good hose down with electro-contact-cleaner but i imagine the solvent has just shifted the oil residue elsewhere on the board as it is stil unresponsive.

the top control panel lights up as it should, but when the presser foot is depressed there is no action.

i will get a hold of some of the cleaners you reccomended (might be a little tricky in seoul, south korea!) and follow the steps today and see if i can get it back online tomorrow.

thanks again for your detailed post!

b700029 - i am fairly sure the oil is conductive, or atleast something in it is as PCBONEZ said..

it is really the only malfunction on the machine that could have caused the short (in my limited guesswork of course!)

Longbow - i aggree, the pump problem was an odd thing to had happened, but i am 100% sure of the cause..

the thread cutting solenoid is housed on the underside of the machine head and needs to be oil cooled by the machines pump housed next to it.

when the pump blocked, it caused the solenoid to overheat and crack as it was starved of the coolant (oil).

once the pump was unblocked, the oil flooded the solenoid through the crack that had developed and managed to travel down the solenoids power line to the mainboard, where things got really catastophic!

crazy i know, but i am very sure of this since my investigations.

terrible luck!


thanks again for your help!

[tttttthomas]

Re: industrial sewing machine mainboard/powerboard issue

hello again

proving hard to track down mean green branded degreaser, could you tell me what properties i should look for in the degreaser to find a good alternative?

is all out enginge/tool cleaner ok?
bicycle degreaser?
or a kitchen/oven type? (i imagine the oven type is not suitable due to caustic additives)

thanks again!

[tttttthomas]

Re: industrial sewing machine mainboard/powerboard issue

following badcaps members advice, i have managed to get my machine back online!

thank you so very much for all your help.

to try to help out others, ill let you know the exact steps taken for the fix.

1. carefully remove all soiled boards, connection and components
2. drench with ecological multi cleaner/degreaser, making sure to hit the board from every angle possible, i went in at 45degrees from left to right, right to left, up to down, down to up.
3. in your shower/bathroom clean out an empty washing up bowl, and fill with warm water, adding a good few squeezes of washing up liquid.
4. submerge your first circuitboard and shake side to side and up and down to force the water into all the nook and crannies, and set the board aside and do the same with the next. and so on.
5. once all of you boards have had a dip, dump the bowl of water and make a fresh one and submerge your first board again. now take a new, soft tooth brush and squueze on a dollop of neat washing up liquid. take out the board, and carefully tease along the boards components and surface, working a lather into the crevices. again, so this left to right, right to left, up to down, down to up to make sure you get every where spotless.
6. after you've toothbrushed, dunk the board and shake left to right, up to down, front to back (under the water).
7. take your shower head (set on warm) and wash off the suds. again, left to right, right to left and so on, making sure you get every angle covered.
8. set your board aside and finish cleaning the rest.
9. once you have a full set of clean (but wet) boards, go outside and use a coat hanger or paper clip (i used huge safety pins, that was what was just lieing around) and clip them to your washing line. you dont want them to be able to swing around to freely (and hit stuff) so make sure they wont slip up and down the line, or fall off your hook.
10. take your isopropyrl (i use 99%, try to use something above 90~) and drench your board again using a spray bottle. left to right, right to left and so on. making sure it gets in everywhere.
11. wait for the boards to dry, this obviously takes different amounts of time depending on your situation, but to be safe leave for a full day. - whilst your stuff is drying, go back to the other connecters and make sure they are clean too, as you dont want to plug crap in to your new shiny boards. you can clean them the same way.

[PCBONEZ]

Re: industrial sewing machine mainboard/powerboard issue

CONGRATS!
.
Obviously the oil was conductive and and that's all that was preventing operation.
I was relieved to hear nothing got shorted such that something actually fried.
[Could happen if the oil was highly conductive vice moderately.]
.
Good job!
.

[bluto]

Re: industrial sewing machine mainboard/powerboard issue

I have a similar issue with an Apex DTA-250 converter box. Except this one was sprayed with silicone spray instead of oil. It was rescued from the trash and I was told that the previous owner tried to 'fix' it by spraying it with silicone spray (maybe to help the electrons get un-stuck?). Unfortunately the previous owner was not a badcaps.net regular so they completely missed the bulging 470uf 25v samaxon cap on the power supply board. So I have fixed that problem but decided to try and clean up the silicone before I power it up again. I sprayed the power supply board with flux remover and then rinsed it with denatured alcohol a couple of times. I did the same for the tuner/video board but skipped the flux remover. I used some compressed air to get them dry but plan to wait a few days before re-assembly and attempting to power up.

However the boards still feel a little 'slick' so my question is should I attempt any further chemical cleanup? I do note that most silicone spray seems to be formulated as non-conductive so it may be that any remaining residue is pretty much benign.

[bluto]

Re: industrial sewing machine mainboard/powerboard issue

well I went ahead and put the converter box back together and I am happy to say that it came back to life!

[PCBONEZ]

Re: industrial sewing machine mainboard/powerboard issue

Denatured alcohol is not a good idea because it's Denatured with various different chemicals [not the same brand-to-brand] and some of them are very bad for electronics.
Use Isopropyl alcohol instead. Doesn't have random chemicals added.

Other than that. - CONGRATS.
.