Dead Berlan cutter

[peterd51]

Hi,

Too cold for spending much time in the workshop but I was out there early in the week cutting a bit of 6mm plate, about 2.5m run. Then I switched to 1mm plate and cut around 15 metres and the cutter stopped working...

with the nozzle and ceramic off there's power there to strike an arc but there's nothing from the HF to start it normally. It used to spark a couple of times a second but now there's nothing.

So I popped the lid off and drew the circuit diagram, at least it was warm in the house!

The HF side is mostly on one circuit board, the bottom one marked up as 'SH-TCDB-01 A8439 2005.02.28'.

I've checked all of the 'silicone' devices with a meter and get readings that look OK bearing in mind I'm not sure what 'OK' actually is for this unit.

The only thing I can't check for sure is the transformer and I suspect it's this that's failed. The bottom of the board has some sort of laquer coat so I can't make contact with the pins and anyway I don't know what pins the windings are on.

I sent an email to the guys I bought it off asking if they could sell me a circuit board and they responded with a warrenty form to fill in!

Warrenty wasn't mentioned in the Ebay advert when I bought it.

I sent the form in and yesterday had a reply asking if I'd checked that the air-flow was set correctly, so I assume they're thinking that the air-flow could be too high blowing out the arc.

At least they're thinking 'right'!

This could be on-going for a while but it's an interesting situation.

Germany may have different consumer laws to us, maybe they /have/ to give after-sales service?

The impression I've had so far is that they have a factory with 'technical' workshops and staff available to sort out problems.

If all else fails I reckon that Shop-River off Ebay could probably source a replacement board from the factory in Shenzen (or where-ever it is). The risk is that I may be buying the wrong board as there are three in the unit...

Regards
Peter

 

[rusty69bus]

interesting.
transformers are standard sizes and can be re-engineered if need be.

 

[JW240]

thats bad luck... i sure hope mine holds up better!

i noticed that the Berlan plasma cutter is the same on the inside as my "Highweld" machine from "Felzen trading gmbh" In Nettetal, Germany. I visited their office to pick up my plasmacutter after some shipping issues and they were very helpful and they claimed to have lots of spares available.

http://jw.cautela.nl/gallery/main.php?g2_itemId=3240

 

[klaatu]

I had very good service from those Berlan people on eBay over my faulty compressor, although it did take quite a while and a number of emails back and forth with various questions and answers. The woman I was dealing with had pretty good English, and it was clear she was translating for the technical guys, who did seem to know what they were doing.

They were on the point of arranging for it to be collected and sent back to them for replacement (at their expense) when I accidentally switched it on while it was part dismantled and it destroyed itself. I had to admit that wasn't covered by the warranty.

Steve

 

[mishka]

I'd be a little wary of probing around inside one of those. Open circuit voltage of plasma cutters is around 200-300V. The HF start circuit will be producing around 10-15,000V, and from what I can see uses a transformer similar to a TV Line Output Transformer (LOPT). The HF is then coupled into the output by that large copper spring-thing at the front.

If it is the LOPT then replacement of the HF module will be easiest, otherwise you'll be needing strong solvents to dig through the anti-corona lacquer on the PCB before you can getyour soldering iron in there.

Still, if its under warranty then best to let the vendor sort it out first.

 

[Barking Mat]

I'm sure it's not this: but there isn't a fuse on the back for the hf unit? I had this problem with a plama.

 

[EVguru]

The HF section is in effect a Tesla coil.

You start with a source of high voltage DC, around 3000 volts or so. There is a spark gap accross the output of this supply and a series connected capacitor and inductor (the primary of the output coupling transformer). The supply charges the capacitor via the inductor untill the voltage accross the spark gap is sufficient to break down the air and the gap 'fires'. The capacitor now discharges into the inductor via the spark gap and the circuit 'rings' at the resonant frequency of the capacitor and inductor giving a burst of high frequency (into the megahertz range) and high voltage (10,000 volts plus) which is coupled onto the torch by the output winding. Due to the high frequency the current will flow only in the surface layer of a conductor (like YOU!) and there is no risk of cadiac arrest, but there is of radio frequency burns or of doing yourself an injury jumping away.

In the Berlan cutter, the initial high voltage appears to be supplied by a switched mode 'flyback' power supply. This may have failed, but it's not uncommon for the spark gap to be dirty or to have erroded and the gap become too big. The quality of these gaps varies a lot between the Chinese manufacturers. Some use propper tungsten electrodes, but some appear to use a pair of relay contacts. The latter can overheat and errode, bend, or even unsolder themselves from the PCB. One possible alternative spark gap (and I've seen this in some European welding equipment) is an automotive spark plug.

 

[mishka]

The quality of these gaps varies a lot between the Chinese manufacturers. Some use propper tungsten electrodes, but some appear to use a pair of relay contacts. The latter can overheat and errode, bend, or even unsolder themselves from the PCB.

Crikey - you're right. Here's a photo from some chap's "Chiry" machine:

http://www.patmedia.net/sta1173/images/DSCF0155.JPG

Top-middle you cann just about make out what looks like a set of relay contacts.

If they're stopped arcing then that would stop any HF being generated.

 

[peterd51]

Hi,

thanks for the advice...

I've been very carefull to let capacitors discharge before removing the lid!

The spark-gap looked clean on mine as I've not really used it much, probably only once a week for a few minutes each.

The last day was definately the most work I'd done with it by a long way and the total run-time was probably 40 minutes or so spread over 60 minutes.

Berlan are sold by Bergland Handels GmbH,Kirchstr. 71 – 73, 08248 Klingenthal, Germany.

As stated above, they've asked a couple of questions. The last one I answered a few minutes ago was have I got the tip at the right distance from the work and have I tried changing the nozzle, etc. I changed all of the 'consumables' when it first stopped working, so I don't think it's that.

When I had it apart I checked the spark-gap to see if it was clean and I closed it down a little to see if it helped.

If it's out of warrenty (as I've been fiddling inside) but they can identify that I've got the right board then I won't mind buying a replacement. As the boards are all identified I could maybe try sourcing one from Felzen if I'm stuck...it's always good to have another outlet!

Regards
Peter

 

[EVguru]

If they don't insist on having it sent back and you end up with a dead circuit board still in your hands, post it to me and I'll see if I can fix it.

You knever know who might need a spare.

 

[peterd51]

Hi,

OK, though you could be fixing it for me yet! :-)

I guess they'll be closed over the weekend so we'll see what emails I get early next week.

What I'd like to see is an email stating "yes, we've seen this a few times and it's always the bottom board so we'll send a replacement"...I'd even be happy with an added comment along the lines "but please send us £20, etc" for postage.

The small-print on the original form that they emailed read along the lines of "we'll pay for postage but if we find that it's not fair wear and tear that caused the problem then we'll charge for postage and for the repair, plus a weekly storage charge until you pay up"...

a (sort of) LLoyds Open Contract and there's no way I'd agree with that!

Regards
Peter

 

[irondarren]

It does sound a little naughty, and something i wouldnt agree with either

 

[peterd51]

Hi,

Here's the circuit diagram for the bottom board...



and here's the board...



From what I can see with my limited knowledge of electronics (I'm more of a digital man, it's either on or off!), the mains 'in' connects to the two pins near the black, square object near the bottom left.

It feeds through the two blue relays into the electronics on the bottom right and back to the big capacitors and the connectors at bottom left.

I reckon that this is all OK as the cutter powers up and supplies enough power to strike an arc at the torch.

The HF components are completely separate, top right and you can see the 'dividing lines' if you look at top of the board, it's pretty obvious where they are.

I reckon the two contacts middle top bring power down from the middle board and either the C2073 or the pins from the top board (middle of photo) cause the blue relay to switch on and off rapidly.

This 'chops' the power supplied to the transformer. The diodes and resistors to the right carry the output through the spark-gap, middle right, to the two connectors on the right.

These have a single wire that wraps around the copper spiral on the middle board and this spiral is part of the output circuit directly into the torch.

I've checked all components with a meter where I could get a connection above the board. As I wrote earlier I can't seem to make contact underneath the board (that special coating that someone mentioned) so I can't check the transformer.

I also can't really check the relay as I don't want to be touching anything with it powered up.

My only concern is if it's a problem with any 'switching' circuitry on the top board then I'd be wasting cash changing the bottom board, and although it's a guess I'm fairly sure that's where the problem is.

Regards
Peter

 

[peterd51]

Hi,

this is still on-going.

They asked me to check the air flow wasn't too high.

Then they asked me to get an electrician to check the voltage into the 'item'.

This confused me a little so I answered asking if they meant power into the cutter...I knew that this was OK as I could strike an arc with the nozzle off, the fan was running and the air solenoid switched on when I pressed the trigger.

I also queried if they wanted a check on the voltage going into the specific board and if so where would it be checked and what voltage should I see. No response to that one!

Last night they asked me to photograph the 'blow pipe' ??

So I took a couple of photos of the torch, one with it as normal and one with the parts disconnected and asked if this is what they mean as I wasn't sure.

So, apart from the slightly different terminology that's probably due to the different languages, I get the impression that they're currently running down a check-list.

I mentioned at least three times previously that the unit powers up as I can strike an arc and it's only the HF start that's not working, but they still asked for an electrician to check the voltage.

I see similar things when talking with 'techie' help-desks (IT, etc) where they know bugger-all and simply follow a check-list before finally passing the query on to 'level-2' where the real techies are.

Regards
Peter

 

[matt1978]

I really hope that you manage to get this sorted out mate.

But this backs up what me and Weldequip have been saying for ages, initially the price looks good for the Chinese fleebay stuff, but when it comes to it there really is no aftersales support what so ever, should anything go wrong

 

[Justme]

I really hope that you manage to get this sorted out mate.

But this backs up what me and Weldequip have been saying for ages, initially the price looks good for the Chinese fleebay stuff, but when it comes to it there really is no aftersales support what so ever, should anything go wrong

Whilst I agree that some times support can be non existant that does not seem to be the case in this instante. Yes its pants support so far but it is support & it does look like that thy are working there way through the likely problems just wanting to make sure sending it back or supplying parts is not the right option.
This was not bought direct from china where your comments might be justified but from with in europe.
Justme

 

[peterd51]

Hi,

well, the way I see it they're offering to pay for postage both ways and repair it under warrenty so they need to know before they spend money that it's a genuine fault and not something daft like it's not plugged in.

If I was at home all day getting my emails regularly then this exchange may have taken a couple of days at 3 - 4 messages per day. But I can only read my emails in an evening so half-a-dozen messages take 6 - 7 days, with a weekend in between.

Plus, there is a slight language problem, someone there is probably trying to translate English to German a vice versa, and that person may not be technically minded. The slight time difference probably also has an affect where they're going home at least an hour before me.

As we discussed before, this would be useless for even semi-professional use but I can manage without the cutter for weeks if I have to.

I still reckon I could buy a complete board from Shop River on ebay at a reasonable cost and have it delivered in a week...but I'm sticking with Berlan for now to see what happens.

Regards
Peter

 

[matt1978]

Well like I said, I really hope that it does get sorted out for you.

Keep us informed

 

[shiftyseamus]

Hi peter, have you had any joy with Berlan?

In my experience their customer service is fairly awfull.

I have been doing some digging around on fleabay and came accross these guys:-

http://cgi.ebay.co.uk/New-Plasma-Cu...yZ113743QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

They claim to stock spares for the m/c and are uk based, so (should) be quicker and easier to deal with?

I have a vested interest in this as I also have one of these machines and am now paranoid about it dying on me!!

Seamus

 

[peterd51]

Hi,

nice link, thanks.

At Berlan I'm sending emails to a woman and teh last email i got was to say that she's passing the photos I sent on to the technical staff.

Hopefully I'll get something other a question from them tomorrow. Ideally they'll state that it's definately the bottom board that's faulty...

Regards
Peter