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  • Dialarc HF no gas

    Hi,

    I have what appears to be a European made Dialarc HF from 1971. You can check images here. Serial number is 7512-10953. I can get it running and I can get an arc, but there seems to be no gas coming out of the TIG torch.

    I took it apart and it seems that the gas solenoid doesn't open. I'm unsure though if the solenoid itself is seized or if the post flow timer somehow interferes with it. I checked the schematics from the manuals that can be found on the website but I can't quite make sense of everything yet.

    The solenoid is connected to two blue wires with the numbers 13 and 1 written on them. When the machine is idling I measure the following:

    Wire 13: 4.48 V AC and 0V DC
    Wire 1: 24.45 V AC and 0V DC

    Pressing the button on the torch I measure
    Wire 13: 17.7V AC and 4V DC
    Wire 1: 30.1V AC and 3V DC

    Above measurements are respective to the electrode as ground with the machine in standard DC mode.

    When I measure the voltage difference between both wires the voltmeter shows 26.5V AC both when the remote button on the torch is pressed and not pressed. This seems fishy to me. I imagine for the coil to energize there needs to be some sort of voltage difference so that a current can run through, once the remote button is pressed.

    Does anyone know what the correct behaviour would look like on the machine?

    Best regards,

    Dan

  • #2
    I'm only finding a manual for a US machine, not a european one. I don't suppose there was a wiring diagram stuck inside the case somewhere?

    Based on the US one, first of all, don't make any measurements between the electrode/work connections and the internal control circuitry - they're isolated (or, at least, should be), and the numbers are meaningless.

    For the US version, it looks like the gas and water solenoids should be 115V. It might be something else in the eu version. Does it say on it?

    Do you have the contactor control switch in the remote position? Does the main contactor clunk and power up the weld output when you trigger the torch? If the contactor control is in standard, the gas valve is disabled. If the main contactor is working with the trigger, then a bad remote/standard switch or bad cr2 relay would be possibilities. If the main contactor is not clunking with your control, then you might look at the wiring and switch in the control, the remote/standard switch, the circuit breaker, that the welder is correctly linked for the voltage you're using, or the main transformer.

    Comment


    • #3
      Originally posted by Bushytails View Post
      I'm only finding a manual for a US machine, not a european one. I don't suppose there was a wiring diagram stuck inside the case somewhere?
      Unfortunately not.

      Based on the US one, first of all, don't make any measurements between the electrode/work connections and the internal control circuitry - they're isolated (or, at least, should be), and the numbers are meaningless.
      Hm, now that you mention it that does makes sense. Thanks for the hint.

      For the US version, it looks like the gas and water solenoids should be 115V. It might be something else in the eu version. Does it say on it?
      The solenoid for the gas has no information on it (any more) unfortunately. Just the brand and at the back some scattered numbers/values. I'd have to check again at home and see what they see. When googling them I couldn't make out the exact solenoid though.

      I might just look at datasheets from newer solenoids of the same make and do some (un)educated guessing as to how mine could work if it did.

      So in the US version you would trigger the remote and then 115V AC would be applied to the valve? Or are the 115V standard as soon as the machine is turned on and in remote position?

      Do you have the contactor control switch in the remote position? Does the main contactor clunk and power up the weld output when you trigger the torch? If the contactor control is in standard, the gas valve is disabled. If the main contactor is working with the trigger, then a bad remote/standard switch or bad cr2 relay would be possibilities. If the main contactor is not clunking with your control, then you might look at the wiring and switch in the control, the remote/standard switch, the circuit breaker, that the welder is correctly linked for the voltage you're using, or the main transformer.
      Yeah, when I switch to standard the contactor "clonks" to always on. When I set it to 'remote' (which I did for all the tests) it only "clonks" when I press the button on the remote. So it seems everything works like it should. The circuit breaker I tested involuntarily and also still works. CR2 I'll have to check again in the diagram.

      Thanks for the tips so far!

      Comment


      • #4
        The solenoids are typical normally closed solenoids, where you apply the rated voltage to open them, which is 115V on the US version, but may be different on the EU version. It'll be whatever voltage is available on the remote contactor connector, for an easy way to check. The power to the solenoid runs through the standard/remote switch and through a pair of normally open contacts on CR2, according to the US diagram, so either of those failing would cause low/no voltage to it. To see if the CR2 coil and control is good, does HF continuous work? A different pair of CR2 contacts is used for the HF continuous setting.

        Comment


        • #5
          I got to fiddle around a bit this week after work. So it appears to be 115V as well on my machine. The continuous option seems to work. There are visible sparks at least.

          Upon further looking at my welder I noticed that some things are pretty different to the schematics and pictures in the manual. I assume they were changed in it's life. But I'm not sure what exactly happened. Where CR 1, 2 and 3 are supposed to be according to the manual I only have one relay. while R3 and SR3 are there, but SR3 in my case is a selenium rectifier. I didn't think semiconductors were around at that time.

          The relay I have there uses line 46 and 45 to power the magnet of the relay which then closes a switch between wire 9 and wire 12. Comparing that with the wire numbers on the schematics it doesn't make any sense to me. Or maybe the numbers on my blue wires don't match the numbers in the schematic anymore.

          I'm also struggling a bit with the schematic symbols that are used, maybe you can help me a bit out there so I can make more sense of it. I highlighted two examples. The circle that says CR2. Is that the contactor relay? Is it the power side of the relay or the control side? And next to TD1 is that a trimmable capacitor called CR2?
          Click image for larger version

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          Or does the circular thing represent the magnet of CR2 and the other thing is the contact that that is set once current runs through the magnet?

          Comment


          • #6
            Ah okay, now I found this. Never seen any one of those symbols at university. Maybe I'm too young. xD Now I just need to figure out why the relay in my machine connects wire 9 and 12.

            At least I get how the schematics work now.

            Click image for larger version

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            Comment


            • #7
              The different numbers are probably because you have a different machine. There's no reason for the european version to be the same as the american version.

              If it looks different inside, you're probably going to have to follow wires to figure out how it's built, if you can't find a diagram for it. You could just have different numbers, or your machine may operate entirely differently.



              Comment


              • #8
                Is this more like it? What AC voltage are you reading across the solenoid... the 26 vac does not sound right... why are you assuming this is an Euro machine?

                Does your machine look like the one in this manual? https://www.millerwelds.com/files/ow...s/O315_MIL.pdf



                Comment


                • #9
                  Dan Man: I didn't realize you'd added pictures of the solenoid. It looks like it says 24-50 to me? That might mean it's 24v, 50hz AC, rather than 115V AC like the US version. This would suggest your machine is very different than the US one. It would also suggest that 26VAC means it should be on...

                  Popscott: The machine is made in italy, the parts are made in italy, and it's 230/50hz...

                  Comment


                  • #10
                    Mud daubers mud in the fittings? If he has 26 vac on the sol it should be opening.. yes I am seeing the pictures now.... Dan...what ohmage are you reading across the isolated sol. coil? If you have 24 volts and a resistance across coil, the solenoid can be dis-assembled easy enough... pull the coil and it looks like screws underneath will let you look inside... pull apart on a clean level surface slowly.... there is a plunger inside the coil shaft and spring with the seal

                    Comment


                    • #11
                      mud daubers are a real problem.
                      years ago I had my "shop" set up under a carport and hadn't attached the TIG lead into my Maxstar 150.
                      long story short when I hooked it back up, no gas.
                      mud daubers filled the connection solid!

                      Comment


                      • #12
                        Originally posted by Popscott View Post
                        Is this more like it? What AC voltage are you reading across the solenoid... the 26 vac does not sound right... why are you assuming this is an Euro machine?

                        Does your machine look like the one in this manual? https://www.millerwelds.com/files/ow...s/O315_MIL.pdf


                        Looks very close but no. The power switch is different and mine doesn't have a coolant valve. The coolant lines go directly to a motor that pumps water from the water tank through the torch.


                        Originally posted by Bushytails
                        Dan Man: I didn't realize you'd added pictures of the solenoid. It looks like it says 24-50 to me? That might mean it's 24v, 50hz AC, rather than 115V AC like the US version. This would suggest your machine is very different than the US one. It would also suggest that 26VAC means it should be on...
                        Yeah I thought the same. I even contacted the solenoid company with the same infos and they weren't able to say what this old solenoid was and how it operated.

                        Mud daubers mud in the fittings? If he has 26 vac on the sol it should be opening.. yes I am seeing the pictures now.... Dan...what ohmage are you reading across the isolated sol. coil? If you have 24 volts and a resistance across coil, the solenoid can be dis-assembled easy enough... pull the coil and it looks like screws underneath will let you look inside... pull apart on a clean level surface slowly.... there is a plunger inside the coil shaft and spring with the seal
                        I tried measuring resistance from outside (without disasembly) and my voltmeter would show open load. Maybe a wire is broken. I was hesitant to open it though because things don't always come back together the way I disassemble them when I'm in a hurry. Tonight I'll take some time and try to carefully disassemble it.

                        However I tried blowing through the valve with my compressor. If blown into input the valve would block, but if blown into the output side air would go through and no visible junk or dirt came out. So I think the valve is alright.

                        Comment


                        • #13
                          If the coil measures open, it's bad.

                          Comment


                          • #14
                            So I opened the solenoid tonight. The valve is very clean and looks as good as new. The coil housing looks very bad. The protective cover around it is partly molten. So I guess there was too much current at some point and the cover melted which lead to a thread of the coil to either melt as well or snap at some point.

                            See Image 1, Image 2 and Image 3

                            Hopefully that's the only thing wrong. I'll try to get a new coil that fits in the casing and see what happens next. I'll keep you guys posted!


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