landy V8 Posted July 24, 2011 Share Posted July 24, 2011 hi all, hopefully someone will have had a similar problem. i have a SIP Topmig 150 and was welding away quite happily when it just stopped spooling wire.it powers up fine just no wire feed.i've had a quick search around and it seems that the PCB can fail on these,but then again it could be the wire feed motor. any help would be very helpful as this has know brought my challenge truck build to a standstill. :( :( many thanks Ralph Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 24, 2011 Share Posted July 24, 2011 The feed motors are often just 12V jobbies in these, but do check before you do this.... Take the side off the machine and put a car battery across the motor, if it turns your PCB is toast (or more likely a small relay or transistor which costs 30p, but you can't buy one for love nor money and end up replaceing the entire board for £50.) HTH Quote Link to comment Share on other sites More sharing options...
rtbarton Posted July 24, 2011 Share Posted July 24, 2011 When you say it powers up fine. do you mean the fan whirrs, or do you get gas and welding voltage as well? Disconnect the motor completly before before connecting a battery to it. It's either 12 or 24 volts, so a 12v battery should give some drive if the motor is OK. This is the circuit of a Topmig motor control, there may be detail differences between models. Have a look here My link Quote Link to comment Share on other sites More sharing options...
steve b Posted July 24, 2011 Share Posted July 24, 2011 Have you checked the wiring to the trigger? and the switch in the torch itself , cheaper hard wired torchs often only use brass blades to contact the wire feed motor hth Steveb Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 24, 2011 Share Posted July 24, 2011 This is the circuit of a Topmig motor control, there may be detail differences between models. Have a look here My link Wow that's hardly rocket science is it! Quote Link to comment Share on other sites More sharing options...
landy V8 Posted July 24, 2011 Author Share Posted July 24, 2011 well,checked the motor and that is working fine.on checking on that forum it looks like it could be the PCB,as they seem to be a bit of a common failure point on the SIP range. Quote Link to comment Share on other sites More sharing options...
Eightpot Posted July 25, 2011 Share Posted July 25, 2011 On my SIP, the small transformer which reduces 240v down to 12v for the PCB and motor failed. If you don't have 12v at the board, this will probably be the cause. I keep meaning to order a small board mounted transformer from maplin, but two years on I'm still using my temporary fix... I soldered two long wires to the board, fed them outside the welder and just attach them to a car battery works a treat. Quote Link to comment Share on other sites More sharing options...
landy V8 Posted July 25, 2011 Author Share Posted July 25, 2011 after having the motor out to find it works ok,i put it back together and it seems to be working again as normal.unless this is a sign that the pcb has an intermittant fault and is degrading and will need changing at some point. we shall see what happens in the meantime. thanks to all Quote Link to comment Share on other sites More sharing options...
roguevogue Posted July 25, 2011 Share Posted July 25, 2011 I suppose you had considered thermal cutout? Quote Link to comment Share on other sites More sharing options...
mickeyw Posted July 25, 2011 Share Posted July 25, 2011 Something I got caught out by - check if there is a safety cutout switch on the door to the wire cabinet. It gave similar sypmtoms to what you describe, everything powered up, fan running etc but the trigger was unresponsive. Had me worried for 20 minutes before I gave the door an inadvertant nudge and everything started working again. All that worry just because the door lock wasn't rotated to the locked position Quote Link to comment Share on other sites More sharing options...
chazsmash Posted July 26, 2011 Share Posted July 26, 2011 Hi, have an older SIP 150 migmate that played me up until i realised it would stop spooling when it got hot, as one of the previous replies said, definitely something in the thermal cut out theory, don't think the hobby type welders like doing continuous streams of weld from the experience with mine but it is 12 years old so they have hopefully moved on in that time. Quote Link to comment Share on other sites More sharing options...
Ruuman Posted August 4, 2011 Share Posted August 4, 2011 my fun and games with my SIP 195 can be found here, http://www.mig-welding.co.uk/forum/showthread.php?t=18884 turned out to be the transformer. Lot's of pics and comments from helpful people Quote Link to comment Share on other sites More sharing options...
simonr Posted August 5, 2011 Share Posted August 5, 2011 That's about as rubbish a motor controller as you could make! If it's the 12v transformer, replace it with a PSU from an old PC. They are fairly bomb proof and mostly give out decent current at 12v (as well as 5v, 3.3v (often), and -12v) I use one in my mill to supply 24,12 & 5v for various things inc driving the 4th axis stepper motor controller. I use 3 in my Electric Freelander with the 5v lines connected in series to charge the 12v vehicle battery. Most computer supplies are just as happy with 220v DC from the traction battery as 230v AC from the mains. The supplies deliver 50A @ 5v - so 3 of them make a 50A 14.8v charger - not bad for free! They were scrap from old PCs. It even occurred to me that 6 PSU's would give about the right voltage to weld with - at 50A continuous. 24 for a 200A 100% duty cycle welder switchable in 50A increments. Cheap and useful for all kinds of things! Si Quote Link to comment Share on other sites More sharing options...
Eightpot Posted August 5, 2011 Share Posted August 5, 2011 ^^ like that idea, got an old pc knocking around so might have a go at upgrading my modular motor drive power pack (car battery). Maplins do some pretty cheap chassis mounted transformers, and I picked one up recently. They don't provide any form of instructions though, and there were five or six wires coming off it?? In order to try to find the right wires for in/out I did some simple testing with a power source and a multimeter - I gave up after the first attempt when I seem to have made a bench mounted tazer which sent me breakdancing across the shed Quote Link to comment Share on other sites More sharing options...
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