hi i was selding today with a rockworth ar 120 mig welder when the feed just stopped then i pull triger i can here it clicking inside i checked the feed moter with a 9v battery and it moving i check the 2 fuses on the pcb there ok can anyone help
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.
Thank you for providing an update, with the good news that you have been able to source a suitable relay at reasonable cost, and that the welder works now. This information will be helpful to others with the same problem.
It's all rather weird really.
I still don't actually know if the relay latches or not, nor if the welder control board sends a pulse for On and then another pulse for Off. If so, why do that? The fact that the relay has to be ordered as "Open" or "Closed" implies that it does latch.
It is almost worth buying one just to get to the bottom of this relay mystery.....
The original JQX-29F-A had only two switching terminals ( i.e. 4 terminals in total including the operating coil ). The welder control PCBs that use it only have tracks and physical space for two switching terminals, hence the need for Dremel'ling if it is replaced by the AliExpress WJ172 equivalent, which has 4 switching terminals.
The datasheet:
WJ172 POWER RELAY Components datasheet pdf data sheet FREE from Datasheet4U.com Datasheet (data sheet) search for integrated circuits (ic), semiconductors and other electronic components such as resistors, capacitors, transistors and diodes.
datasheet4u.com
makes clear that it can be ordered as "WJ172-1A, 1B, or 1C-12VDC". The "1A" version is NO, the "1B" is NC, and the "1C" is both ( i.e. it can be used as SPDT ). In the "1A" version that is required here, the NC contacts used in the other two versions are not wired, put the pins are still there.
So something like a SSR-40 DA would do fed by cable's
Don't see why latch required other than 4T.
Perhaps we are seeing to much in the NO/NC and it was a cheap item, available in 3 configurations
this is brilliant, i have an old 140amp welder (Kende) i bought, back in 2007, it stopped working in 2015 because i couldnt find a suitable relay.
i found a relay while cleaning up (T92P11D22) which i was planning on replacing the JQX 29F with, i thought let me just check if i can find one now - a google search brought up the ali express item.. YES!!!
wait.. NO or NC? thats the question...
id have to desolder the relay or try and remove the cover to find out - so thought id google again and found this forum and a post by eddie on another thread... along with pics which showed an NO relay
excellent.. ordered 2 of them .. finally ill be able to fix the machine with which my welding journey began.. and let my son use it to learn on
hats off to eddie for the info on the link to this thread - hence registering on the forum ... which brings me nicely on to my next post (a question about settings on my current 280amp MIG which ill post in a few hours) hopefully i can get to the bottom of the mystery!