Snap on YA 240 A

[John Farmer]

I have a snap on YA240A welder. Wire feeder stopped working so I installed a new control board. Wire feeder works now but it feeds at
Max wire with potientomer at 50% of range. Potientomer ohms out correctly at 5k ohms. Can I change the 5 k pot to a 2.5 k pot to double my range to get a finer adjustment ? Will this hurt the new control board ?


Thanks for any reply.

 

[skotl]

Welcome to the forum

Is it possible you've fitted a logarithmic pot instead of a linear one?

In terms of swapping it out for a different value, that shouldn't cause you any problems. You could also put a separate 2.5k pot in series with the control panel pot so that you have an adjustment of the "top end".

 

[tom2207]

welcome to the forum ,,, there are some clever eectrical folk on here who will know , im just not one of them.

 

[addjunkie]

@eddie49 might be the man to answer this

 

[hotponyshoes]

Have you checked the pot wiring? Could the plug have been put back the wrong way around?
The pot socket might be marked on the pcb showing pot connections.

 

[eddie49]

Hi and welcome to the Forum!

This is a general circuit diagram for the Century 117-024 MIG welder, sold by Snap-On as the YA-240 :

https://ch-delivery.lincolnelectric.com/api/public/content/de661538c71b4f66ad645a522399a39e?v=0ada5ed3

The speed control pot is R2, a 5k variable resistor. The three wire colours are grey, green, and white, with grey on Pin 1 of the board. The circuit diagram of the control board itself is not available.

An earlier Forum thread discusses the circuit and the off-board driver transistor:

J

Thread 'wire feed on my snap-on ya240 does not stop and won't change speed'

Aug 27, 2021

wire feed on my snap-on ya240 does not stop and won't change speed. I disconnected the wire feed controls and the gun leads for the switch in the gun and it still runs.

• john3794
• Replies: 7
• forum: Cebora & Snap-on

Maybe your welder originally had another fault as well as the speed control board - such as the off-board driver transistor, or perhaps the new board is not exactly compatible? I would suggest checking the output of the small transformer T1 - it should be 24v AC.

Replacing the 5k pot with a 2.5k one may or may not solve the speed range/adjustment ratio issue. It depends on how the circuit works, if it uses current through the resistor or voltage across it as a potential divider... a 2.5k may work, or perhaps a 10k !