Syncrowave Hall Effect Sensor

[malcolm]

Many thanks Jake for suggestions and a manual. My Syncrowave 300 was having trouble working at the right current. There do seem to be faults with the hall effect sensor.

On the circuit board R54 has a crack in the surface, and the insulation on the wires to the sensor itself seems to have failed - the black wire has welded itself to the yellow wire. In an attempt to separate them I pulled the yellow wire out of the sensor.

Do spares tend to be available for these machines still, or is it better to replace the resistor and see if I can repair the sensor wire?

 

[fingers99]

I'd be stunned if a decent electronics place couldn't find a replacement sensor and repair the board.

 

[Jake SS]

Malcolm

The resistor R54 may still be OK but see if you can measure it and replace it.

The yellow wire to the hall, can you still get to it to solder a new wire to the end ?

The PCB should be fine, just clean it up and redo the soldered joints if they look dodgy (use a magnifier to go over them), check all tracks.

I have tried to find PCB spare part number according to the one that is on the board but no luck, not listed in anything that I have.

Try the repair first, I have some other options if that does not work.

A Miller serial number would really help, have a look inside there may be something in there somewhere.

Cheers

 

[malcolm]

I can't see the end of the wire in the sensor. Also I think the insulation might have burned off the wire - it looks more copper than yellow.

Probably a bit beyond me to work out why the insulation burned off. Hopefully just a fault in this unit rather than somewhere else. I've pm'd rosepuds (techarc) who has agreed to have a look and who should be able to find a new sensor if necessary.

On the plus side I've found a few poor connections in the spade connections at the back of the control panel which I've cleaned off. Everything else looks OK so fingers crossed it will work with this bit fixed.

 

[Jake SS]

More than likely just age and some corrosion causing excess resistance, overheating wires, components etc.

Give all connections, plugs, terminals, etc a good clean up while your at it.
Also if there is a wire loom with wires bunched together "free" them up and check to see if they have started to overheat/damage insulation.

Rosepuds should be able to sort it for you.

 

[malcolm]

There are a lot of wires tied into looms. I'll check them - might point to other faults if I find any overheating. I'm working through the connectors - hundreds of them in there!

Would have been good to post the machine off to someone for fixing, but it's such a big heavy thing it's impractical. Still, it wasn't completely broken before, so the sensor fix and a clean up will hopefully have it up to scratch for a few more years.

 

[malcolm]

Some further investigation today - I'm wondering if the foot pedal could have caused a trouble too. Seems to have been messed with with wires replaced, no stop to prevent distortion when stood on, and the carbon brush that wipes against the resistor broken and lifting off. I recall current defaulted to max in the range when using the remote current control, but remote contact worked OK.

Should the foot pedal look anything like this inside? I'll check the resistance value and see if I can effect a fix.



Going to have to stop taking it to bits - I'll forget how it fitted together.

 

[Robotstar5]

Going to have to stop taking it to bits - I'll forget how it fitted together.

This is where digital cameras come in handy, you can take pictures of everthing and delete them when finished.
I also find a notebook handy to record what wire etc. goes where as you don't want to introduce faults!

 

[Disco_Mark]

This all looks very familiar malcolm. I am afraid mine went back to the place it came from in the end as it was still under warranty, so I can't be much help. I do have a few pictures of my fault finding forrays though if they are of any use?

Cheers
Mark

 

[malcolm]

I'd been wondering how yours was getting on. Glad you had a warranty. Are you thinking of getting another? I've decided I like the inverter TIGs but don't want to budget for one at the moment - they are really quiet without all the fan noise and transformer hum, and much easier to carry around.

Did you take any photos of the inside of the foot pedal? Mine has been modified and it would be interesting to see what the original looked like.

 

[shenion]

Malcolm, that looks similar to my footpedal. I think the only difference on the older Miller ones is the value of the variable resistor.

I can take some picts if you want.

 

[malcolm]

Photos would be great. I think the lever on mine has been re-designed, and I was wondering what was supposed to hold the carbon brush wiper at the correct distance, or indeed if the wiper should be a carbon brush at all. It'll need a new wiper as this one doesn't spring.

 

[shenion]

Here you go:

Wiper close up:

Switch close up:

Maybe the lever was modified or just a different version. The distance on mine is adjustable via the clamp screw at the end.

 

[malcolm]

That's fabulous, thanks. The potentiometer and contactor switch look the same on mine. I'll buy a new wiper and add a stop to the pedal so it doesn't twist the mechanism on full travel. It'll be cool to have a functioning foot pedal.

 

[shenion]

No problem. Although the spiders living inside the pedal were not amused

On the top of the box is a bolt to be used as a stop. Looks like yours is missing as there is a hole there:

 

[malcolm]

Thanks once more - that's the sort of solution I was going to aim for . Your photo makes it easy now. Please apologise to your spiders on my behalf.

One thing that struck me as strange is the bolt threads on the Miller are metric. For anything made in the UK in 1979 they would have used imperial fasteners, and I would have thought the US would have been even slower to adopt the new fangled standards.

 

[Disco_Mark]

Malcolm, mine is coming back - hopefully this week, and hopefully fixed! Apparently both the circuit boards will be replaced - ie the main control board, and the HF board.

I still have the footpedal, and will happily take some pictures if they are still required?

Regarding the metric/imperial fastener thing - mine is all metric as well. Apparently it was made under licence in Italy which is why mine is badged Interlas as well as miller, and the serial number does not show up as a miller number. What does the serial number plate say on the back of yours?

Cheers
Mark

 

[Jake SS]

Malcolm
Have sent a manual for foot controls, should help as well

Cheers

 

[malcolm]

Thanks for the manual - that does help a lot. I should have enough on the footpedal to make it work again. Next the watercooler

My Syncowave also has Interlas written on the sides and a serial number that doesn't look up on the Miller site, so it could well be Italian made. There are hand written numbers on the transformers and the 1 is written in the European style, but I can't see any other evidence of country of manufacture. Might explain differences in the foot pedal.

 

[malcolm]

It's back up and running again

Rosepuds repaired the hall effect sensor and I went around cleaning up all the connectors. Counted them up as I went along - there are about a million of them.

Tried it on arc first - perfect, amps seemed about right. Then to TIG and the HF start was really weedy. Adjusted the contacts and it worked but still possibly a little weak. AC seems a little weedy too, so possibly I've messed up a connection - will have another look later on. Also the pulse and start current still don't work (they never did). And I still need to fix the wiper on the foot pedal.

There's something to be said for welders that aren't 30 years old - Parts availability for the Miller, new or secondhand, is poor - so can be expensive if you can find the parts. Also I've been eyeing up the enormous space the Miller occupies. Might be useful for a large workbench.

Good to have it back in action again. Thanks again everyone.