Kende no wire feed

[eddie49]

"it clicks no feed no spark...the relay coil is open"

It appears to be impossible to obtain an exact replacement for the JQX-29F-A relay. There are some indications it may be a very special component which latches "on" and requires reverse polarity voltage on the coil to force it off. I'm not sure if this is really true. You could try a generic relay with a 12v coil. The contacts on the original are rated at 40A 240vAC, but a generic 12v heavy-duty automotive-type relay should be OK.

EDIT: I believe that relay number L90AS-12W is a suitable replacement.

However, you say "it clicks" - what clicks ?

 

[johnrev]

Hope this isn't the end of this thread! Surely Paul will come back and let us know how things have worked out.
Can't believe how many OP's ask for help and the likes of Mike and others spend time and effort offering their expertise to fault-find a machine and the OP then just disappears. Hell I get annoyed just reading the posts without any resolution. Mike must pull his hair out at times.
Come on Paul let's hear how you got on.

John

 

[a111r]

It is annoying when that happens! PaulC7 was last seen May 29 2014, so I doubt he'll be back with an update.

The ongoing theme of the thread, to me, is that Kende are not good machines, being troublesome to repair.

 

[johnrev]

Hells teeth I didn't notice when the OP first asked just the date of the last post on this page. Dammit I was hoping to find out how or if the machine got sorted. Really like reading these fixit threads- bit like a detective novel!!
I've been spending many hours reading through posts and replies and marvelling at the patience and good humour of the guys on here who give their help to get our sick machines back up and running. So many faults seem to repeat over and over with very similar causes and cures.
I've been helped several times to sort machines (Topmig and Britweld) with the SIP needing all the usual wirefeed mods and the Britweld the usual sortout of an old machine with a lot of wire having passed through it's gun.

Guess that's the great thing about a site like this with a community of guys with an amazing range of expertise who are willing to help those of us with less knowledge and often less cash than we really need. T'internet is a wonderful thing.

Thanks to all on the MW forum
John

 

[Hutcho]

Lol , I’ve got one here doing the same thing , little relay clicks , big one won’t click , hold contacts down and welder works , changed small rectifier but still the same ,

 

[Hutcho]

Problem solved - it’s the big relay at fault

 

[paulwhatever]

CIRCUIT DIAGRAM To Hutcho and others. A friend asked me to look at his welder - no wire feed. I found in the end it was the big KENDE relay, difficult/expensive to source in the uk.
Coil open, unwound/rewound it, 1 break and no overheat damage, probably just wire stress. To get an understanding of how it worked I drew up 2 Circuit diagrams, which I am attaching here. The first - Paul.jpg is how the components are approximately laid out out on the circuit Board. The second paul3.jpg, is how the original designer would have laid them out on a Schematic diagram BEFORE making a circuit board from the schematic. Hope this answers a lot of Questions.

 

[Hutcho]

CIRCUIT DIAGRAM To Hutcho and others. A friend asked me to look at his welder - no wire feed. I found in the end it was the big KENDE relay, difficult/expensive to source in the uk.
Coil open, unwound/rewound it, 1 break and no overheat damage, probably just wire stress. To get an understanding of how it worked I drew up 2 Circuit diagrams, which I am attaching here. The first - Paul.jpg is how the components are approximately laid out out on the circuit Board. The second paul3.jpg, is how the original designer would have laid them out on a Schematic diagram BEFORE making a circuit board from the schematic. Hope this answers a lot of Questions.

View attachment 290635 View attachment 290636

Brilliant Seems to be a very weak relay in these

 

[Reedweaver]

I would to love the relay you used to fix? Is it just a standard 40amp 240vAC?

 

[eddie49]

Hello and welcome to the Forum !

If you are referring to the "unobtainable" JQX-29F-A relay, it has a 12 volt DC coil and contacts rated at 40 Amps.
Apparently, it has a weird "latch on / negative pulse for power off" operating mode ( ? ). I have never confirmed from a circuit diagram that this is true, and internal photos of failed relays seem to show a perfectly standard-looking component, but so many people request the original version, so it may be something special....

There is an ongoing thread here:

Help needed

I have a Powercraft No gas turbofan cooled welder 25-130 amp. I have no wire feed. The machine stopped in the middle of welding. I can just about read a meter so I am having difficulties. I can hear the relay click when I press the trigger. I have voltage on the diode. In desperation, I have...

www.mig-welding.co.uk

where another Forum member is in process of sourcing a substitute relay mounted on a daughter-PCB from Poland.

 

[Reedweaver]

Brilliant. thankl you

 

[Hutcho]

The relay I tried on pigging off the board to make sure board is working was a normal sip relay nothing special - and it worked on and off

 

[alanans]

ok people i found a relay but is it normal open or closed https://www.aliexpress.com/item/100...00030332044694!sea&curPageLogUid=1JxEbQFkBW2y

 

[Scalarocco]

The link is for a SPDT relay. It will have pins for normally open and normally closed.

 

[eddie49]

ok people i found a relay but is it normal open or closed https://www.aliexpress.com/item/1005004629632336.html?spm=a2g0o.productlist.main.3.4812317ezUF62c&algo_pvid=711a1420-4f76-4e93-b722-5e8fd2a224de&algo_exp_id=711a1420-4f76-4e93-b722-5e8fd2a224de-1&pdp_ext_f={"sku_id":"12000030332044694"}&pdp_npi=2@dis!GBP!6.13!6.13!!!!!@2145288516714361675468020d0748!12000030332044694!sea&curPageLogUid=1JxEbQFkBW2y

The JQX-29F is a strange latching relay, which apparently is pulsed to switch on, then holds itself latched closed, then a second pulse on the operating coil will turn it off. The manufacturer ships relays in either of two stable initial states - On or Off. You need the "Off" version.
However, if you hear a "click" inside your welder, it may mean that the relay is in fact OK. Have you tried to meter across the contacts, checking for closure ( i.e. no voltage across them ) after the click? Do you get low voltage AC out of the main transformer secondary after the click, and DC ( 15 to 30 volts ) after the rectifier?
Even if the wire does not feed, can you strike an arc at the tip of the MIG wire? The main welding voltage will also be running the wirefeed motor, via the speed control part of the PCB. If there is no arc voltage, the MIG will not spark and the motor will not turn.

 

[alanans]

the click inside coming from another relay i removed the old one and gave it a 12v charge but nothing moving i pushed the relay switch part over and the wire feed works so its defo this relay just got to wait 2 months for delivery or do anyone know a replacment i can get in the uk thank you

 

[eddie49]

I don't know of any UK-based source for this part.
A company in Poland offers a pin-for-pin replacement using a normal relay and a daughter board:

zamiennik przekaŸnika JQX-29

It costs £5.64 plus postage. In the past I have written Emails in Polish for forum members to order the part, and I can do this for you. I have not had feedback about the shipping time. This thread has details of the process:

Help needed

I have a Powercraft No gas turbofan cooled welder 25-130 amp. I have no wire feed. The machine stopped in the middle of welding. I can just about read a meter so I am having difficulties. I can hear the relay click when I press the trigger. I have voltage on the diode. In desperation, I have...

www.mig-welding.co.uk

 

[alanans]

would this be ok https://www.amazon.co.uk/gp/product/B01A8FLD6Q/ref=ox_sc_act_title_1?smid=AIF4G7PLKBOZY&psc=1

 

[eddie49]

That item is a relay with a 12 volt coil, but I do not see any mention of it being a latching relay, so no, I don't think that it will work.

The correct component gets activated by a pulse and then stays "On" by itself, even tho' the coil power has gone. A normal non-latching relay would come on briefly, but then open.

 

[Seadog]

I used a lot of self latching relays for and alarm system that I built in around 1990. They're not that uncommon on my opinion.