Hf arc start addition

[Nickedemuz]

My hf generator broke on my Telwin Supertig AC/DC and a new one is about 350€ plus tax so I’m thinking about building my own. Looks like a fun project
I’ve googled a lot but I’m still pretty unsure of how to go about it. Since it’s a AC/DC I just want the arc start function when I’m welding steel with DC but I guess it should always be on when I’m welding aluminum with AC?
Any hints/videos of how I should progress?

 

[James1979]

Can you just replace the board? I don’t know that machine but usually you can change the board out. I bought a tig from here and the member had fixed it by doing just that.

 

[premmington]

Can you just replace the board? I don’t know that machine but usually you can change the board out. I bought a tig from here and the member had fixed it by doing just that.

That is very good idea.

Take it apart - get the PCB out - get a number off it. Then contact Telwin - I think they are Italian. Not a bad company - they may well have resonably priced spares avail.

You have nothiing to loose - it is called a "machine autopsy" - its dead you can't do it anymore harm!

 

[Nickedemuz]

Thanks for your replies
Unfortunately the hf generator is a single unit and it’s filled with epoxy. Guess they didn’t want anyone to fiddle with their stuff. I have contacted Telwin and as you say, they really care about their customers even if it is a hobbyist with a 30 year old welding machine. Unfortunately the spare is 350€ + tax and shipping and that’s a lot in my opinion. That’s why I thought this might be a good enough project to learn something and not get broke at the same time

 

[James1979]

Jeez! That’s a lot for a spare board I wonder if a generic board will fit. My welder is a brand I can’t find any info about at all so I’m sure the board wouldn’t be a genuine replacement. I may be wrong. @steviec_lj can you shed any light on it please? It’s the 161 I’m talking about

 

[Jim Davey]

Find out what the input voltage is to the board and what it’s physical dimensions are. I may be able to sell you a brand ne replacement HF pcb for a lot less than what you’ve been quoted, if there’s room to fit it that is.

 

[Nickedemuz]

Yeah, I thought it was way too much as well.
I don’t mind a generic board as long as it works
Jim Davey, I’m definitely interested in that.
I don’t think the physical dimensions will matter that much, it is a pretty big welder with lots of room Does this picture show enough info?

 

[Nickedemuz]

This is a picture of the hf generator

 

[Jim Davey]

The universal HF board I use needs to be supplied by 240v. As long as you have a supply that’s live while welding for ac, and is live for arc start only in dc it will work.
You could use a step up transformer if your original Hf board operated on a lower voltage.

 

[skotl]

This is a picture of the hf generator

Flippin' modern rubbish, only lasting 33 years

 

[Nickedemuz]

Jim, I have four wires going in to the box so I’m guessing one pair is live when on ac and one pair is live when on dc. I’ll hook up the multimeter tomorrow and see what it says. Do you want to send me more info in a pm about your hf board?

 

[Nickedemuz]

Jim, I measured the ingoing pairs but I’m a bit confused. One pair (nr 1 and 3) always show 235V when I power it on. The other pair (10 and 12) show 1.5V when I turn it on and 64V when I push the button on low setting and 73V when I push the button on high setting. I just tried one amperage setting so it was about 60A on low setting and about 120A on high setting. Is this normal and would I be able to use one of your hf boards on this?

 

[Jan-DIY]

Seems to be ok.
235V Supply
60-75V trigger to modulate HF strike.
Got a EGT SIG 2.4 module from an old Dalex TIG here.
But it is 42V AC supply.
230-42V transformer are very common.

 

[Nickedemuz]

Thanks Jan, then I know it looks ok from that side. Then I am pretty sure it is the hf generator that is bad.
I’ll try removing the potting on it and have a look see just for fun. Otherwise some kind of replacement will be acquired