Cebora pocket turbo 130, wire feed motor judders

[garethp]

Hi,

I've had the welder for years and always struggled to get a consistent weld, some times its good and other times its rubbish. I decided to get to the bottom of it recently and narrowed it down to the wire feed motor or pcb. I've taken the motor out of the feed gearbox and when its running it judders, apart from when its running near max speed when it runs smoothly. It does it most of the time but not always - when it runs smoothly I get a decent weld.

Has anyone else come across a similar problem?

 

[rikrobson]

Does the motor feel rough when spun by hand? if so it could be motor bearings, a worn shaft, or the bushed/commutator. its a 24v motor so you could get a replacement. the motor/gearbox assy is available. the sltenative is one of the all in one wirefeed-eurotorch assemblies and convert it.
try a 12v motor and Lamp of a similar wattage in series (totaling the power rating of the original motor) or a 24v lamp to prove off the PCB. If the new motor judders then the PCB is at fault if using a lamp it will flicker. I suspect the motor though as the motor drive is via thyristor

 

[garethp]

Thanks for the info and suggestions

I'll try and have a look this weekend, I had thought about trying a different motor to narrow it down to pcb or motor but wasnt sure about the voltage as it has no markings on it. I hadnt thought about using a bulb....

 

[brettb]

Same issue with Cebora 130 wire feed PCB or motor

GarethP,

Did you have any luck with this? I have a similiar problem.

Driving the motor (disconnected from gears) and adjusting wire feed (a potentiometer?) gives erractic motor operation.

I've found that:
- No-load voltage supplied by PCB is between 2 and 18v. At 80% knob setting, voltage is ~ 9v. 80%-100% give a steep voltage increase. Voltage seems steady - hard to tell on a digital meter.
- motor runs okay off 12v and 3v batteries.
- motor was full of guck - cleaned. It has bushings and is very simple. Brushes worn but okay.
- at maximum wire speed, motor runs evenly and fast (for 90% of the time)
- the relay ('contactor') in clear plastic is visually operating okay.

I *think* this points to the voltage regulator on the PCB, (or maybe a dirty contactor - which only shows itself under load?)?

Can anyone shed light on this?

 

[Cobs]

Check the contactor in the torch - dirty/pitted contacts can cause the motor to run erratically.

 

[mike 109444]

If the "potentiometer" is of the carbon track type just think of the old tv or radio volume control that would cracke at certian positions and would clear for a bit if operated full on and full off, or a spray with wd40. This would only be a temp fix. for the cost < £3 at maplins? worth changing.

 

[brettb]

I think the contactors only activate the relay and aren't in the motor circuit, but I'll clean 'em. The pot is a rotation type which is a carbon track type, I think. I'll investigate that with WD40 and replace. I'll post my results soon.

Thanks more your help guys. More suggestions welcome!

 

[Sean]

More suggestions welcome!

its been mentioned about the contacts in the torch trigger burning

also i found that the pressure roller on the feed mech started getting really rough its just a bearing race and so can be replaced for a couple of ££

 

[brettb]

Results of trying the above:

I prised open the potentiometer (not made for this) and sprayed in WD40. THIS WORKED. Nice one Mike. Wire now feeds and speed is fairly constant, but not great. I'll replace the whole PCB or the pot. Replacing the pot will be difficult due to specific size requirements.

Thanks to all, and hope this help another.

 

[mike 109444]

brettb Can't see the pot being any thing special. should be an off the shelf one. Try Maplins or if desprate try ebay : ) Note with any found on ebay check where the supplier is ie far east = slow boat from china.... Still will be cheep enough <£5

 

[mike 109444]

Opps just relooked at your location Dooh. Maplins = electronic parts shop chain here in uk not sure what you have down there.

 

[brettb]

Mike - yeah I think I can find one, although I maybe have to mount on front then wire to PCB as PCB holes and mounts are very specific. No dramas. I just need to match the resistance (says "2K2").
I *think* this is a linear (not log) pot.
Being in Australia (!), China isn't that far... but I'll use Jaycar (a local 'Maplins' perhaps?).
Another tip I heard to test this (for others reading) is to pull the shaft of the pot while testing. If this makes it work, the pot is assumedly wornout.

 

[AndyMV]

Thought I'd just update this thread with my own recent experience. I have the same issue with erratic wire feed, and thought I'd give the replacement potentiometer fix a try. It's a linear 2k2 pot with a 45mm shaft length. To save messing about, I wanted something that would be a straight swap. After a lot of searching (seriously, A LOT), I found a Piher PC16SH-10IP06222A2020MTA at Rapid Electronics (UK based, but ship internationally). This is almost identical to the original part. The pins exit the case at the wrong angle (just need to be bent through 90 degrees) and are missing two mounting pins. These pins can be swapped over from the original pot, and although they are soldered to the board, they have no electrical connection.

The new pot cost about £6 (which was mostly shipping). Definitely cheaper than a new PCB.

Here's a PDF of the datasheet. I think the exact item would have the same part number apart from starting PC16SV (for vertical) but the one I ordered only took a few moments to modify.

Although this made an improvement, it unfortunately didn't fix the problem for me. I tested the motor so the issue is obviously elsewhere. Torch contacts as someone else suggested perhaps? Hopefully this information will save a lot of hassle for anyone trying the same thing.

 

[AndyMV]

Here's a picture of the mounting pins getting swapped across and the difference in pin orientation.

 

[Rig Pig]

Have you tried a new liner, torch liner and tip? I have seen some cheap mig wire that wasn't a constant diameter, that caused some interesting problems till it was spotted!
Your not using a 5kg reel are you? My old welder isn't happy with the weight on the drive.

 

[AndyMV]

I haven't, but the problem is evident even with the motor removed from the housing. It spins very 'lumpy', and after a while there's an obvious change in speed. I probably need to check it with the torch removed from the circuit, but I haven't really looked into how to do that.

 

[Fuchs915]

Hello all, looks like I am another member of this club. Wire feed is erratic, sometimes good, other times very stop/start. All runs OK when I am not welding, with the wire feeding through consistently, but when I go to weld, it becomes erratic. I am a novice welder, and electrics are like black magic to me, so can someone in very basic terms explain what the causes might be. I see the wire speed control might be an issue, what else? If parts need replacing, where do I get them? It has a new liner and tips, if that helps.

Thanks

Kevin

 

[rikrobson]

Hi Kevin, When you are welding are you also watching the wire feed? is the wire feed turning ok, but the wire slipping? this could be a problem with the wire sticking in the tip or the swan neck.

 

[Fuchs915]

Thanks RR, I think you have a point. The wheel does slip. I have some spare tips, so will try new one when I get some more gas, but what about if it is the swan neck, how is that fixed?

Thanks

Kevin

 

[R Kraft]

The wire should feed nearly effortlessly, it is just a piece of wire sliding down a tube and through a tip.
I have never seen the cebora pcb, but if it is an scr type, it will sometimes help to add a 100uf capacitor across the motor.