trying to help out an old friend with a autolynx loss of welding voltage the issue pretty much suspect voltage control board , after spending hours online cannot find anything wiring diagram wise can anyone help ?? Tia ......
Hello and welcome to the Forum. These machines were a clever design and built with high specification components, but very poor assembly and soldering quality. First step would be to check the whole machine for loose or corroded connections, and bad solder joints on the PCBs. Similar issues were discussed in this earlier thread: https://www.mig-welding.co.uk/forum...roblem-controlling-voltage-so-they-say.77476/
yes thamks been over the board need a compleat board diagram with values otherwise it's a stab in the dark ......
I believe that on the Autolynx the welding output power is adjusted by a controlled bridge rectifier. There may be four SCRs ( thyristors ), or two plus two diodes. I would suggest checking that voltage is available across the input to the bridge, then monitoring the gates of the SCRs to check for firing pulses. This would need to be done using an oscilloscope. Then trace the gate and cathode wiring from the SCR module to the PCBs. The trigger pulses will be generated by a variable timing circuit, synchronised to the AC mains. This may perhaps use a 555 timer chip, or a monostable, or a transistor astable multivibrator circuit. I think the trigger signals are coupled to the SCR gates via a potted circular ferrite ring pulse transformer, fed from one or more medium power driver transistors.
Thanks for the more in depth answer unfortunately i dont have access to a scope you are correct there is a 555 chip but reading from other posts it's the spot/stitch weld timer control , but as i said cant realy work out what does what on the control board,without a diagram BOC seems to be secretive about the workings of this unit ........cheers ..
I have a fair amount of info on these machines, unfortunately it's stored on my work computer and I am at home right now. However, if you PM your email address, I will send you what I have when I get into work next week. I know I have circuit diagrams for all the PCBs and from memory, I think there is a chart showing component references and values. Be warned, the original drawings were a bit rough and mine are copies of the originals. Should give you enough to work on. FWIW BOC were far from secretive, as all the diagrams were included in the original owners manuals. You'd be lucky to get anything more than a block diagram saying 'Mains in --- Welding current out' with todays machines. Dave
