View Full Version : WSE 200; modify (for food pedal current adjustment)

04-25-2012, 06:25 PM
If you have such a welder, without possibility to connect a Foot Pedal,

http://www.abload.de/img/kgrhqzhie9s-muhvbpj7gz4kfn.jpg (http://www.abload.de/image.php?img=kgrhqzhie9s-muhvbpj7gz4kfn.jpg)

i've found out how you can modify your welder to connect a Foot Pedal, to control via this the "welding current" and "Start/Stop" welding.
here is the thumbnail, of the Image, ~7MB
click on the thumbnail, to open the image, and then click on the image, to get the full size
http://www.abload.de/thumb/gimp144l7d.jpg (http://www.abload.de/image.php?img=gimp144l7d.jpg)

for using "ON/OFF" via the Foot Pedal, use the Connector for the hand Switch on the Front Panel, because this is electrical interference suppressed.
For the Foot Pedal Potentiometer & ON/OFF Switch, use a shielded Cable, and an extra wire for Ground connection (Pedal to Welder housing)

when i find out other Informations, like function, features, control voltages, and signals, i will post it here.
not hesitate to ask or tell your own experiences
but this thread should only be for this type of WSE and very similar types. (because of the simplicity)
photos from my Modification are following when my foot pedal are finished

for everyone who knows what the hot end of the soldering iron is, this modification should be easy ;-)
do not modify anything if you don't know about electricity and/or what potentiometers are for, or you have two left hands

Unplug the device before opening.
I assume no liability for any damage

12-21-2012, 03:37 AM
HI, I have the same machine but it has the foot pedal attachment.

Using it last night I found that it developed a fault and that the HF start is perminatly on, running with nothing pressed meaning that the gun is perminatly live when you turn on the machine. I checked if it was the pedal or trigger by unplugging them, but it appears something else is running the HF start, do you have any idea what I need to be looking for when I get the cover off later.

I can post some images of the internals if that will help.

12-21-2012, 04:30 AM
what i know, about, the PCB, the HF ignition is not directly controlled, it is Active while Pressing the Torch oder the Foodpedal ,
i.e. when Argon Valve is open, then HF is on.

is also the Gas Valve open?
When not, then, the Fault is on the HF PCB and not on the Control PCB.

The HF PCB is, (front view) left, at the Bottom,

12-21-2012, 01:27 PM
Thanks for the reply.

So I understand -

If the Gas Valve is open while the HF circuit is on, then the issue is with the control circuit.
If the Gas Valve is closed while thw HF circuit is on, then the HF board is faulty.

I can post some pics if they will help at all.

I will try to take a look tonight.

12-21-2012, 01:44 PM
OK - I just checked it out.

The gas is on while the HF circuit is running.

Does that help at all?

I can still weld with the unit, but it is constantly running on a very low setting, I can dial in more power with the foot pedal and weld ok, it just never turns off.

Does that help give an idea what the issue might be?

12-21-2012, 02:18 PM
i think some of a capacitor at the HF part is gone.
so the HF, turns not off.
but wait, i will check under what circumstances the HF turns off.

12-22-2012, 11:19 AM
I think you're right I think it's the HF board.

Looking at the circuit it looks like the HF board drives the gas valve.

I have disconnected the HF start plug from the front control panel as described in you diagram and continuity checked to confirm the circuit.
With the connector disconnected the HF and GAS continue to run.

I am thinking it's the HF board screwed to the bottom of the welder that has failed, now I just need to work out what's wrong and replace the part(s).

12-22-2012, 12:00 PM
oh thats interesting... the gas continues, while disconnected....
may be, that, the Signal from the control Board, is only a short "1"
and the GAS/HF Board works like an Trigger. 1 = ON again 1 = OFF (for the Gas) (may be = 0 for triggering, or short resp. open) (we have to find it out)
And for HF, 1 = HF for several seconds. (so check the Components at the OUT side, in height of the HF PArt of this Board, u can see 2 PCB Lines going from there)

12-29-2012, 04:23 PM
Done a bit more of a shake down, here is what I found.

The Gas is OFF when the circuit is pulled from the main control board!

I checked some of the components on the HF board, I have two diodes that seem to be behaving strangely I took some measurements and I get a result in both directions, not sure what to replace them with or what might have caused the fault though.

I have included the results of my tests and picture of the board so you can see what I have tested.
Check out the pictures here: http://www.fr10ker.co.uk/FR10KER/Site_v1/Projects/Project-Welder%20Repair/Welder%20Repair.htm

In your opinion does the HF being on seem consistent with the failed diodes?
What diode rating do I need?


12-29-2012, 09:44 PM
Check the diodes out of circuit to be sure, and to find replacements, cross reference based on the type number printed on the diode. If they are used to supress transientson the adjacent relays (across the coils) you may simply be reading the relay coil resistance.

- Tim

12-29-2012, 10:46 PM
I see, there are two Relays on the Board.... SMI-24VDC-SL-A one is for HF part.
The small blue one.
Knock on it... may bee it stuck (J03)
(the Area from CP1 -> X1 -> X3 ist the HF part, the others (big capacitors are for smothing the Powersupply line)
so there is no need to measure D10 or so...

Ur Board is slightly different to mine, (mine gets the Power from itself, and the Trigger from another connector.
But ur Board is easier to understand.

12-30-2012, 12:56 PM
I thought I was looking at the wrong circuit, thanks.

I have over laid the tracks on the components for ease take a look.


I have tested the relay with small power supply on the coil and a meter on the outputs and it works fine switching making contact etc.

Do you think it's the board supplying power to the HF board thats at fault.

What makes the HF board active, I am assuming it's the coil side of the relay being powered up?

The HF circuit has 2 power feeds neither seem to switch and provide constant power, I thought the power would switch on the relay to activate the HF board.

Do you think the fault lies on another circuit board?

12-30-2012, 06:03 PM
where are going X3 and X1 (or ist it 4 i can't see it good enough) within ur welder?

12-31-2012, 06:20 AM
I have uploaded some images to show where they connect.


12-31-2012, 06:38 AM
OK, then X3 is the Trigger, and X4 is the Source.....
when u pull X3 the HF should not come on.

when u pull X4 then also, but the Relay is switching though

now the Question is, what does the HF shut of after ignition.
I dont think, that the HF Part it self does it.

But u say, HF is permanent Hot.
also when u not press the Button on the Torch or pedal.
then only (in mi mind) the Trigger route (X3 and follows) fails.
But u also say the Relay is switching?! hmmmmm

12-31-2012, 06:41 AM
Moment, When HF is permanent hot?!
then u should hear that.
because the spark gap, and u can see it at the spark gap.
whet it is HF/HV
is it as, u hold the torch to Ground, and it zapps sparks? and u hear it?

12-31-2012, 08:13 AM
When the machine is switched on the spark gap is live and I can see the spark, nothing connected to the front, pedal or gun switch.

Here is the test:

X3 X4 Relay Spark
on on on Yes
off on on No
on off off No

The relay is switching as soon as it's powered up so X4 is supplying the switch voltage constantly.

I tried to read the voltage on the board that's connected to X4, I can't get a reading it's flashing on my multimeter and I can't read the result, possibly high frequency?

12-31-2012, 10:34 AM
i need the datasheet of the Relay...
Thats crazy, why is te relay on when X3 pulled and off when x4 pulled and x3 on.
Then the Coil of the Relay, is not at the parallel pins of the Relay.

12-31-2012, 10:46 AM

Here is the datasheet

Why they have connected the two Switching pins?

Could it be, that the Relay acts as simple OnOff SquareWave (multivibrator)?
to supply the Transformer with rectangular Voltage?
to transform it in High voltage?
It seems to be.

then it seems to be, that where X3 is connected , a little voltage is a life also when the Torch is not on.

12-31-2012, 10:52 AM
When I say the relay is on I mean the relay's coil is activated.

X4 drives the coil side of the relay (switches the HF On Off)
X3 constant power feed.

The relays coil pins work as I have energised them and done a continuity test on the switch side I think it's in working order.

I don't think I understand the analysis of the issue, you have a much better understanding of these things than I.

I think X4 drives the coil side and switches the coil on / off switching the circuit side, without x3 connected the circuit isn't energised.

I think that x4 should only be powered at a certain point when the trigger is pressed for example and this is stuck on.

12-31-2012, 11:38 AM
Ok I have gone out and took some more images to try help...... LOL it's getting funny.

Right the last image 7 of 7 shows the machine on with the spark gap active on the HF board with no connections on the front of the unit.

Then the rest of the images try to show the various connections broken and the spark gap so you can see the result.

Take a look - It's cold outside in the garage so the images are kinda rushed.


Oh happy new year to you...:jester:

12-31-2012, 12:07 PM
I must have been asleep - have it all the wrong way around, I see what you're saying about X3 being the switch and X4 being the power....

My head hurts. He he

12-31-2012, 04:50 PM
That's interesting that the JD3 relay appears to be for "pulsing" the high frequency circuit, rather than for turning it on/off.

Perhaps X4 is not supposed to always be powered on, but rather is supposed to remain unpowered until the torch switch (or footpedal) requests for the arc to be on?

Another thing I noticed from your helpful "reverse engineered" schematic is that there are diodes (D3-D6) involved in the high frequency circuit, which would appear to polarize the circuit. I wonder if the arc starting might be more effective in one direction (e.g., EP HF) than the other direction (e.g., EN HF). This would be easy enough to try by simply reversing these connectors to test - (maybe I'll give this a try on my machine for kicks.)

01-09-2013, 04:25 AM
I have had the front control board out of the set to see if I can find a faulty component.
Nothing is obviously cooked so I started to test each component, I can't understand why the HF would be hot constantly :(

It occurs to me as many of these machines are so similar a fact file with block diagrams, pictures and models etc as a resource / sticky would be worth creating, Fokker has done some great work as have many others it would be nice to see more of it collated in one place...

I am depressed at my lack of skill in electronics.... :rolleyes:

01-10-2013, 04:06 AM
Moderator! Can you please remove my Hijack from Fokkers thread so the usefulness of Fokkers thread isn't lost!

Can my discussion be moved to a new thread?


01-10-2013, 09:39 PM
Probably made in china .