Thanks. Millers not in 4 t. Prob a fault in board ,I’ve got used to triggering it again after stopping, so I’ll carry on regardless, them 300 a contractors are dear just to try it, ! I’d buy one if I knew for sure, I’ll send photos of other later, but will try a separate 24v supply first,as you suggested thanks again ,ah I put euro on and gas valve 2 wires,and 240 v valve
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Even though the Sealey Mightymig 150 is a simple and quite common welder, I have had no luck in finding a circuit diagram for it. I think the control board has the part number "0R0503-1", and there is a photo here:
www.ccw-tools.com
The two push-on tags on top of the relay will be mains feed in and out to the main transformer.
There are 7 wires on the white multi-pin connector. Two will be the Live and Neutral AC mains feed to the primary of the small transformer mounted on the board. Two will go to the wirefeed motor. Two will be Positive and Negative from the DC output of the rectifier to feed the speed control part of the board. That is a total of 6 wires, leaving only one wire for the torch trigger switch, but two wires are needed to make any circuit complete. Therefore, the On/Off trigger circuit must also rely on the Positive from the rectifier.
So when you tried to use the Positive and Negative from the rectifier to run the new PWM speed control board, the welder would no longer trigger on from the torch switch because the Positive wire also has to still be connected to the original control board.
If the wiring at the white 7-pin connector needs clarification, please remove the board and post a photo of both sides, showing the components and the tracks underneath.
Sealey M/Mig150.32 - Control Board | CCW-Tools
Sealey M/Mig150.32 - Replacement Control Board for the Sealey MIGHTYMIG150 - Gas/No-Gas MIG Welder 150Amp 230V.Please see main product parts list below for deta
There are 7 wires on the white multi-pin connector. Two will be the Live and Neutral AC mains feed to the primary of the small transformer mounted on the board. Two will go to the wirefeed motor. Two will be Positive and Negative from the DC output of the rectifier to feed the speed control part of the board. That is a total of 6 wires, leaving only one wire for the torch trigger switch, but two wires are needed to make any circuit complete. Therefore, the On/Off trigger circuit must also rely on the Positive from the rectifier.
So when you tried to use the Positive and Negative from the rectifier to run the new PWM speed control board, the welder would no longer trigger on from the torch switch because the Positive wire also has to still be connected to the original control board.
If the wiring at the white 7-pin connector needs clarification, please remove the board and post a photo of both sides, showing the components and the tracks underneath.
Thank you for the photos. There are in fact only 6 wires on the white plug, not 7 as I guessed!
I think the "missing" wire must one of the two AC mains wires, which means the primary of the small transformer on the board gets one leg of its AC feed from the push-on tag on top of the relay.
( On the black HF102F relay, the two push-on tags on the top - which are the Normally-Open contacts - are also brought down to two solder pins on the printed tracks, and one of these links to the primary of the small transformer.)
The pins of that white connector are numbered 1 to 10, starting from the right. Four of them are not used ( 1, 3, 4, and 10 ). By looking at the printed tracks underneath and identifying the components that they connect to on the top, I think that the wiring is as follows:
Pin 2 - Black, AC mains
Pin 5 - Red, to wirefeed motor
Pin 6 - Black, to motor
Pin 7 - Black, to trigger switch
Pin 8 - Black, to -ve of main rectifier
Pin 9 - Red, to +ve of main rectifier
You could confirm if this is correct by following the wires in the harness from the plug on the board out to the remote components.
To use your new PWM speed controller board by powering it from the existing DC welding supply, you would need to transfer the red and black motor wires from Pins 5 and 6 to the PWM output terminals. Then cut the black wire at Pin 8 and move it to the negative power input terminal of the PWM controller. Finally, link a wire from the red wire at Pin 9 to also go to the positive power input terminal of the new board.
This will still allow the torch trigger to switch the welder on, and the wirefeed motor speed control portion of the original board will be disabled.
I think the "missing" wire must one of the two AC mains wires, which means the primary of the small transformer on the board gets one leg of its AC feed from the push-on tag on top of the relay.
( On the black HF102F relay, the two push-on tags on the top - which are the Normally-Open contacts - are also brought down to two solder pins on the printed tracks, and one of these links to the primary of the small transformer.)
The pins of that white connector are numbered 1 to 10, starting from the right. Four of them are not used ( 1, 3, 4, and 10 ). By looking at the printed tracks underneath and identifying the components that they connect to on the top, I think that the wiring is as follows:
Pin 2 - Black, AC mains
Pin 5 - Red, to wirefeed motor
Pin 6 - Black, to motor
Pin 7 - Black, to trigger switch
Pin 8 - Black, to -ve of main rectifier
Pin 9 - Red, to +ve of main rectifier
You could confirm if this is correct by following the wires in the harness from the plug on the board out to the remote components.
To use your new PWM speed controller board by powering it from the existing DC welding supply, you would need to transfer the red and black motor wires from Pins 5 and 6 to the PWM output terminals. Then cut the black wire at Pin 8 and move it to the negative power input terminal of the PWM controller. Finally, link a wire from the red wire at Pin 9 to also go to the positive power input terminal of the new board.
This will still allow the torch trigger to switch the welder on, and the wirefeed motor speed control portion of the original board will be disabled.
No, that extra wire on the HF102F, taking switched power out from the relay to the new gas valve, will not change anything. I only mentioned the relay when I was trying to work out why there were only 6 wires on the white plug and not 7.
