Cebora Auto Star 180 no power

[gunnag]

Hi All, I have inherited a Cebora Auto Star 180 and have been trying to get it working. When I turn it on, its completley dead, no light on switch and no fan running, nothing all dead. When I opened up the cover, there was a large amount of dust and some of the connectors looked corroded.

I have done some basic checks as follows:-
- plug socket fuse is fine
- there is 240v at the on/off switch and it does switch the power on/off
- there is no or very little power to the fan. I did manage to detect a couple of volts but thats all

I did notice what looks like a thermal cutout clipped to the front of the large transformer, wires from this go to the switch so maybe this is the source of my problem?

Any thoughts on what may be wrong and how to fix it would be appreciated.

 

[mike 109444]

Hi Gunnag. Seams you have done some checks and know how to use a meter. You can check the thermal cutout by (unplug machine first!) disconnecting one side of it and set your meter on ohmes (lowest setting) then put probes across the cutout and you should see a short ie 00.00 (or very near that) this means cutout is ok. if you don't get a reading then it has failed "open" and will req replacing. Take it from there and report back on your findings.

 

[Robotstar5]

Give it good blow out with compressed (dry) air then disconnect and clean all the connectors witha bit of fine emery cloth or wet & dry paper.

 

[gunnag]

Cheers Guys, will check the continuity on the thermal cut out & report back tomorrow.

 

[gunnag]

Today I had another go at getting the mig running, without any success.

I blew out all the dust using a leaf blower and then checked the continiity at the thermal cutout.

There was no resistance at the thermal cutout (zero ohms) so IM assiming its OK and IM now mystified as to why its not working.

I was wondering about the on/off switch and whether its wired correctly. There are four terminals, the lower two have black cables coming from the mains transformer, the upper two are blue/black and connect to the thermal cutout, fan and someother bits I cant identifty. I have measured the voltage accross the two upper terminals (i.e. the two blue/black wires), with the switch off there is no voltage, with the switch on there is 240 volts between the two top terminals. Is this the correct way to test the switch?

All info welcome.

 

[Robotstar5]

I was wondering about the on/off switch and whether its wired correctly. There are four terminals, the lower two have black cables coming from the mains transformer, the upper two are blue/black and connect to the thermal cutout, fan and someother bits I cant identifty. I have measured the voltage accross the two upper terminals (i.e. the two blue/black wires), with the switch off there is no voltage, with the switch on there is 240 volts between the two top terminals. Is this the correct way to test the switch?

Not sure about the 2 black wires "coming from the transformer"? surely they come from the mains in to give your 230V supply on switch.

Personally I'd connect one meter lead to the live pin on the plug, set it to Ohms and trace the wiring through, then do the same for the neutral side. Readings should be <2 Ohms (ish) anything higher means it is reading through another component (transformer etc.) and you've lost the direct path.

 

[gunnag]

THanks for the reply Robotstar5, as far as I can see, the mains wire enters the back of the machine and then is connected to small transformer mounted near the top. There are two black wires coming out of the transformer which connect to the two lower switch connecters.

I will try the ohms test as suggested and see what happens.

 

[Robotstar5]

If you can post a picture of the insides it might give us a few ideas of what to check.

 

[gunnag]

Yes, pictures will be published asap

 

[gunnag]

Here are some pics of the inside, not very clear unfortunatley, but you can see the power cables going to the transformer and on to the switch, you can also see the thermal cutout dangling.

 

[NotANormalCoder]

The AutoStar range were good machines and pretty simple. When I get back to the office tomorrow, I will find the circuit diagram but for now, I am fairly sure that the fan is 240V and wired across the mains supply after the switch, so if the switch is faulty, this could explain lots. Digital meters have a habit of showing 'phantom' readings so double check for 240v into the auxilliary transformer and 24v (I think) output. If you are not sure of the switch, try bypassing it.
HTH Dave

 

[gunnag]

Thanks for the info dave, since there are several transformers in the machine, can you explain where the auxilliary transformer actually is? Is it the transformer connected directly to the mains input before the switch?

 

[NotANormalCoder]

The auxilliary transformer is the one above the fan, with orange/red terminals, mounted on the vertical panel that separates the wire feed system from the rest of the innards. Follow the mains input cable - 240V Live & Neutral comes straight onto two of the main contactor terminals and two lighter wires come from these same terminals down to the on/off switch. Check all the terminals here for good connection. The mains then goes through the switch and then on to the auxilliary transformer input. Turned on, you should see 240V across the marked terminals here - if not, you either have a broken mains lead (common problem - check continuity) or a faulty switch (common on older machines - try bypassing). If no joy, check around the auxilliary transformer for a fuse - some machines had strange little fuses mounted in a sort of plastic thing on the transformer. Grab the tab and pull out, the fuse is in the bit in your hand! Can't remember if there was a remotely mounted fuse.
It is important to note that the fan should run all the time if the machine is turned on, even if the thermal overload is faulty (and it should be shorted except when overheated). These fans do fail, either seizing or burning out but you should still be able to measure 240V across its terminals. My guess is that you don't actually have 240V getting this far. Check and post back.
Dave

 

[gunnag]

Thanks for all the info guys, I think I now have the problem sorted.

Turns out that one of the wires in the mains lead was broken near the entry to the body. I cut the cable back to an unbroken section, rewired it and it all works! The fan rotates and on pressing the trigger, wire did appear from the torch.

The next step is to get some suitable mig wire. Although I was able to make the wire feed from the torch, it stopped after a few seconds and on inspection, there is no spool and it was the remanants of the old wire being fed through.

Does anyone know what size spool fits this type of MIG? IM guessing there are varyious standard size spools so any info on which would fit a cebora autostar 180 would be appreciated.

 

[NotANormalCoder]

Excellent news - It's always worth checking the simple stuff first.
Either 5Kg or 15Kg spool sizes will directly fit this machine - small reels (1Kg?) don't fit as their central hole is too small to go over the spool holder. 0.6mm or 0.8mm diameter wire both work well but it depends on what thickness of material you plan on welding. 0.6mm best for panels and a little light chassis work, 0.8mm will do small stuff with extra effort but is better for chassis and light fab work. Make sure you clean out the torch liner and fit a good tip of the right size and you should be away.
Dave

 

[gunnag]

I thought I would post an update on the Cebora 180 I have been restoring.

Having got the power supply working, I then bought a 5kg reel of 0.8mm wire from Screwfix, it was a bargain at around £9.00. I managed to get the wire mounted and fed through the harness up to the torch.

So far so good, the wire feed seems fine and the wire speed control works. I then thought I would try some test welds. Using the lowest power, I was able to weld some light weight steel together. I then gradually increased the power to no 3 setting and hit a problem with the household mains ring circuit breaker tripping out.

The mains ring circuit breaker is rated at 16a and I believe the MIG plug fuse is only 13a. Does this mean my mains ring circuit breaker is faulty?

I did notice that the mains ring circuit breaker will trip out simply by pressing the torch trigger without forming an arc.

Any thoughts on why my mains ring circuit breaker is tripping would be appreciated.

 

[keith19]

If that really is a household ring circuit it should have something a bit bigger than a 16A breaker on it. I think they are usually 32A.

It is generally advised not to be welding off a ring circuit. An up to 180A machine will have quite an initial surge, and other electrical items may be connected and in use. This would make a trip-out much more likely, especially with only a 16A breaker.
Better to have a dedicated cable supply direct from the consumer unit, if possible, with its own breaker.

Probably all that is actually happening is that the initial surge when you switch the trigger is tripping the 16A breaker; the surge would not be on for long enough to blow your plug fuse, especially if this only happens when you switch the power upwards to a particular setting.

 

[NotANormalCoder]

Keith19 is about right, except that I think household rings are usually 20A. Yes it's normal for a welder to take a largish surge as the main transformer is energised, and this happens each time you press the trigger, even if you don't strike an arc.
Another thing that many forget, is that a long lead from the point of supply to the point of use can make a difference. Many people use their machines in a garage or workshop that is supplied by a fairly thin cable and this causes a voltage drop. So in practice, the voltage available at the end of the cable drops and the current taken from the supply increases - so, the fuse/trip supplying the circuit tends to blow more often. I've seen many cases of welders used on silly long extension leads and surprisingly, the fuse at the welder doesn't blow but the fuse at the start of the lead does.
Make sure you have a decent thickness of supply cable and change the circuit breaker for at least 20A. Trips do get tired as well and this could be the cause.
If the welding condition is good (smooth with decent penetration), then you can almost certainly eliminate the machine as a problem.
Dave

 

[Windy Miller]

...I've seen many cases of welders used on silly long extension leads and surprisingly, the fuse at the welder doesn't blow but the fuse at the start of the lead does...

Yeah I've noticed this too in the past - WHY does that happen?

 

[keith19]

Dave would be able to tell you technically better than me, but I guess it's because when the initial surge hits the nearest plug fuse to power source, there is also some resistance in the cable if it's a long thinnish cable, causing volt drop.

Volt drop in the cable increases current draw to try to compensate, so the plug fuse nearest to power source has to deal first with a big inrush of current, and blows before this inrush can get to the other end.
All this is happening pretty well instantly.