P&H Welder: Troubleshooting an Inop Older Welder?

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I'm assisting some folks install an older P&H welder into a hackerspace.  (see link at   I3Detroit)  Its an older machine, but apparently has a pretty good reputation from what folks on weldingweb are saying.  Model #: DAR300HFGW (not sure of last two characters)Manual here: http://www.tpub.com/content/welding/...3-14/index.htm We believe that the machine was operational before it was moved.  When I plug it in, and turn it on, I get power.  I can hear the argon flowing whenever the machine is on.  (Is that right preflow = always on?  Seems expensive.)I was suspect of the pedal, so I took that apart before I even turned the machine on. I could see a loose wire sticking out of the junction at the foot pedal.  Turns out that was an unused wire.  The microswitch works well, the footpedal mechanisms are all sound.  The resistor has a crack in it, but according to my volt-ohmeter still works as a voltage divider at every stop (0 to 11 ohms) I only have the tig torch / cable system for output.  No go on stinger cable.  When I step on the pedal, there is a large increase in the noise the machine makes.  Not sure what is going on.  (Could be transformer noise, could be HF starter..) One thing (in hindsight) that I did was turn full counterclockwise the two knobs that control the high frequency starter circuit.  I originally misread these, thought they were for A/C adjustment.  It wasn't until I got home last night and did some reading that I realized my error.  (I'm not entirely sure that is my problem)  I've played with this thing in both A/C output and DC output.  nothing.  I did scratch starts with the tungsten and nothing.  One thing that I did notice.  There is a selector switch for A/C, DC+ and DC-.  When rotated, the selector doesn't seem to detent.  This surprised me.  I would have thought there were be a heavy detent at each of the three stops. When you move the lever, you can definitely feel significant force, so something is moving inside.  (I guess its something else to check when I open this puppy up today.)Here is my question for you electrical gurus.  1) Can I use a simple volt-ohm meter (VOM) to read voltage across the output to ground when the machine is turned on to see if I'm getting power there?  With a constant current device won't that screw up the VOM?2) Can I scratch start the tungsten against the work piece to help me determine if the HF starter or the welder output is whole?   (note: I actually did this, but no juice, no spark, nothing...)  Is this a valid test?Things yet to verify:Verify there is continuity from tungsten to the hook up end of the hose.Verify jumper connections at the input area are correct.  (someone else told me they were right, but I didn't yet check for myself.)Verify spark gap (0.006" per the manual)Listen more carefully to see if the HF is operational.Visual inspection inside the box.Other ideas?  Oh, and its a hacker space, with full electronic lab and tools available, including oscilliscope.  I just don't want to break anything with high current screw ups.  Any other ideas on things to check?Many thanks in advance,zipMetro Detroit

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Reply:Any volt ohm meter should be okay to use,as long as the HF start is turned off.Running 3500 volts of 1mhz juice through an Vohm meter is a good way to kill them.
Reply:Update from today's trials:I was able to figure out that is no risk to use a VOM to read open circuit voltage.  Funny, but the front of the machine includes that number hand stamped on the ID plate.  The VOM readings matched those reported for both A/C and D/C within a volt or two.  And yes, I did shut off the HF when I did so.I was able to get the machine totally up and running.   The biggest thing I made improvements on was the High Frequency gap setting.   I cleaned them up with a soft cloth, they were in pretty good shape, no heavy burns or anything, reset gap to 0.006" (per the manual.)  Not sure why, but they were set quite low.Other problems that I went thru included poor ground at work surface table top (+ other stupid stuff...)The one thing I was not able to correct was the argon gas solenoid.  The gas flow starts immediately when the machine is turned on.  Not sure if something is wrong, or if its wired that way.  I can't believe its intentionally designed that way.. why would they include a post flow timer, if the gas flows ALL the time when the power is turned on.  that doesn't make any sense... So, the minute you are done welding, run over an push the off button.  And don't turn it on again, until just before you are ready to run a bead.  (mumble, mumble, mumble... )Anybody else been here on the gas solenoid thing?Many thanks,Zip
Reply:post flow timer may have failed. It is common for TIG welders to turn on the gas at power up then turn it off as the post flow timer times out. The post flow timer is reset every time the remote control is pressed. starts timing again. Is the timer electronic or a mechanical clock timer. Miller make a nice timer that runs on 115 volts. fits the older TIG welders. 330 abp and syncrowave 250. comes with a knob and scale
Reply:Does it have a water cooled torch?  Water cooled torches have a bad habit of the conductor inside the hose coming apart. You can have a HF jump at the torch but no weld when this happens. Keep HF turned off connect a meter to the terminals, short the torch to the work clamp. See how far the voltage drops if any. You can also measure from one end of the torch to the other while the torch is touching the work clamp. A good torch will read almost no voltage. A bad torch will have a high voltage reading.
Reply:

Originally Posted by ccawgc

post flow timer may have failed. It is common for TIG welders to turn on the gas at power up then turn it off as the post flow timer times out. The post flow timer is reset every time the remote control is pressed. starts timing again. Is the timer electronic or a mechanical clock timer. Miller make a nice timer that runs on 115 volts. fits the older TIG welders. 330 abp and syncrowave 250. comes with a knob and scale
Reply:Still troubleshooting this beast.  I've cleaned up the post flow timer.  Its works, kinda sorta.  The switch seems to be functioning correctly but its wired into the machine wrong.  Its supposed to start the timer after the foot pedal is released.. then run down according to the time set on the dial to a stop.I have two problems. 1) The allen head setscrews are stripped out, and I can't re-adjust the red dial to the correct zero to time out.   I'm going to have to figure a way to get them out of there and replace.  They are VERY small.. approx 1/16" allen wrench size.  I think I'm going to try and make / modify an easy out to fit the setscrew.  Anybody else got any ideas on how to remove two very small, very stripped set screws?2) Somehow the wiring that feeds the switch is backwards.  The timer gets power when it shouldn't be.  In otherwords.. this machine powers up the inert gas solenoid at power on.. then it runs for approx 45 seconds at which time the timer shuts down all inert gas, no matter where you are in running your bead.   Have a nice day.  Zing.  The wiring diagrams for these machines REALLY suck.. They split every relay into energizing coil and switch output, then show these as two seperate items on the wiring diagram.  Ugh. To make matters worse, every wire is numbered at each end, but the numbers are different at each end of the same wire.  (Looks like they made the wires as a kit for the manufacturer..)  To make matters worse, there is a common board for every junction connection. Instead of going from relay to switch, you go from relay to common plug in board and from there to switch. Every wire is color black. There must be 200 wires in there, and its very messy.  I think I'm going to have to sit down, re-create the wiring diagram from scratch using a Volt Ohm meter. That is going to take days and days.   Ugh. Why do manufactures make junk like this.  How can they possibly stay in business? (Duh.. )  I've found wiring diagrams, kinda sorta, that get me a little tiny bit closer, but I'm still pretty far away.  At this point I can cheat the welder to run inert gas when ever its powered up. Thats expensive and a waste of gas, and I'm worried that the on/off switch will wear out from the excessive use.Anybody else been here before? ref:http://campkahler.com/files/P&H_PartsList.pdfcampkahler.com/files/p&h-dar-300-manual.pdfAnyway, thanks for listening to my rant..zip.
Reply:you may have two options. fist is to get a tig torch with a valve and forget about the timer.Or get a post flow timer from miller that is used on the ab330 and syncrowave 250.It is a nice timer that runs on 115 volts.. The purpose of the post flow time is to keep the gas flowing just long enough for the tungsten to cool down. This help keep oxides off the tungsten and keeps it ready to weld again. and if you keep the torch close to the weld it does the same thing for the weld.
Reply:I've got an even older P&H 400 amp straight AC machine. I've used it for stick welding for nearly 20 years. It was used for tig welding of aluminum Gravel truck boxes prior to that. The tig stuff has mostly been stripped off, but I did set it up to try out on Aluminum using a tig torch adapter (attach stick clamp & gas feed to adapter) It tig welds just fine except there is no foot pedal control , which makes thin aluminum difficult to do.I got an old Arctrol pedal for the machine and wired that up according to the schematic listed above for the DAR300. My machine is a DAR400, but I suspect the wiring of the pedal is the same.With the pedal connected it had no effect on output. I had a look inside the machine and saw that only one wire is connected to the "Remote Output" receptacle. The receptacle has four leads as does the pedal, 3 hot plus ground, or two hots and a neutral plus ground, I'm unsure of which it is.Does anyone here have knowledge of the wiring for the pedal control of these old welders?thanksGlenLast edited by worntorn; 05-10-2011 at 05:18 PM.
Reply:I know this is a really old post, anyone out there that can help me diagnose a no start/spark issue on an old P&H like the one pictured above? General diagnosis procedure would be helpful too.
Reply:

Originally Posted by zipzit

I'm assisting some folks install an older P&H welder into a hackerspace.  (see link at   I3Detroit)  Its an older machine, but apparently has a pretty good reputation from what folks on weldingweb are saying.  Model #: DAR300HFGW (not sure of last two characters)Manual here: http://www.tpub.com/content/welding/...3-14/index.htm We believe that the machine was operational before it was moved.  When I plug it in, and turn it on, I get power.  I can hear the argon flowing whenever the machine is on.  (Is that right preflow = always on?  Seems expensive.)I was suspect of the pedal, so I took that apart before I even turned the machine on. I could see a loose wire sticking out of the junction at the foot pedal.  Turns out that was an unused wire.  The microswitch works well, the foot pedal mechanisms are all sound.  The resistor has a crack in it, but according to my volt-ohmeter still works as a voltage divider at every stop (0 to 11 ohms) I only have the tig torch / cable system for output.  No go on stinger cable.  When I step on the pedal, there is a large increase in the noise the machine makes.  Not sure what is going on.  (Could be transformer noise, could be HF starter..) One thing (in hindsight) that I did was turn full counterclockwise the two knobs that control the high frequency starter circuit.  I originally misread these, thought they were for A/C adjustment.  It wasn't until I got home last night and did some reading that I realized my error.  (I'm not entirely sure that is my problem)  I've played with this thing in both A/C output and DC output.  nothing.  I did scratch starts with the tungsten and nothing.  One thing that I did notice.  There is a selector switch for A/C, DC+ and DC-.  When rotated, the selector doesn't seem to detent.  This surprised me.  I would have thought there were be a heavy detent at each of the three stops. When you move the lever, you can definitely feel significant force, so something is moving inside.  (I guess its something else to check when I open this puppy up today.)Here is my question for you electrical gurus.  1) Can I use a simple volt-ohm meter (VOM) to read voltage across the output to ground when the machine is turned on to see if I'm getting power there?  With a constant current device won't that screw up the VOM?2) Can I scratch start the tungsten against the work piece to help me determine if the HF starter or the welder output is whole?   (note: I actually did this, but no juice, no spark, nothing...)  Is this a valid test?Things yet to verify:Verify there is continuity from tungsten to the hook up end of the hose.Verify jumper connections at the input area are correct.  (someone else told me they were right, but I didn't yet check for myself.)Verify spark gap (0.006" per the manual)Listen more carefully to see if the HF is operational.Visual inspection inside the box.Other ideas?  Oh, and its a hacker space, with full electronic lab and tools available, including oscilliscope.  I just don't want to break anything with high current screw ups.  Any other ideas on things to check?Many thanks in advance,zipMetro Detroit
Reply:

Originally Posted by Hardsun1

I know this is a really old post, anyone out there that can help me diagnose a no start/spark issue on an old P&H like the one pictured above? General diagnosis procedure would be helpful too.
Reply:William,I have to say, I was completely shocked that I received a response to my post, so let me start by saying thank you.I have had my machine for close to twenty years, and unfortunately was not able to use it for about the past 6 years at all. The machine in total is still much of a mystery to me in regards to the controls and settings, If I could pick your brain on those, I would be very appreciative. For the no spark/start issue I had, I removed the contactor, disassembled and cleaned all connections, removed the points (couldn't get a gap gauge .006 in between them) cleaned and gaped properly. Finally had no continuity from the torch to the power connection, replaced the power hose/cable. Now I have a spark and foot pedal control. I'm in the process of going through the machine and cleaning all connections and removing the corrosion that has accumulated. Regarding the controls, how best to adjust the "phase shift" and "intensity"?Again thanks for the response, I'm in a position to start using the great 'ol welder again, I really enjoy older well made tools. Much thanks,Julien Ramirez.
Reply:Curious who made P&H welders? I think they were good machines back in the day.
Reply:P&H made them, not rebranded from someone else. They designed and built fine welders for many years. 1965 or 66 I think was the end.  There is a website on the history of the company. The story goes that they were unhappy with the welders on the market so they had their electrical engineers design and their shop build them. For use in their heavy equipment and overhead cranes. Sent from my iPhone using TapatalkSteveMiller Dialarc 250 (1990)Miller Maxstar 140 STR (2003)Lincoln SA200 Redface Pipeliner (1966)Lincoln MP210 (2015)Victor and MECO torches
Reply:They had features that other top end machines had.
Reply:Does anyone know how to clean the selenium plate stack on a welder?
Reply:

Originally Posted by Hardsun1

Does anyone know how to clean the selenium plate stack on a welder?
Reply:

Originally Posted by Sparkie1957

P&H made them, not rebranded from someone else. They designed and built fine welders for many years. 1965 or 66 I think was the end.  There is a website on the history of the company. The story goes that they were unhappy with the welders on the market so they had their electrical engineers design and their shop build them. For use in their heavy equipment and overhead cranes. Sent from my iPhone using Tapatalk
Reply:Sounds GermanSent from my iPhone using TapatalkSteveMiller Dialarc 250 (1990)Miller Maxstar 140 STR (2003)Lincoln SA200 Redface Pipeliner (1966)Lincoln MP210 (2015)Victor and MECO torches
Reply:

The one and only P&H I ever messed with says proudly on the face of the machine, Milwaukee, WI. That might be their corporate headquarters, I’m not sure but it seems logical geographically.  Miller is made in Appleton, WI.; Lincoln in Cleveland, OH; Hobart Bros in Troy, OH.  It’s hard to be sure because they got out of the welder business sometime in the late 60’s then the corporation was acquired by Joy Global.  Sent from my iPhone using TapatalkSteveMiller Dialarc 250 (1990)Miller Maxstar 140 STR (2003)Lincoln SA200 Redface Pipeliner (1966)Lincoln MP210 (2015)Victor and MECO torches
Reply:P&H had a lot of different divisions and I think were sold off at different times. The welders look very similar to other US made welders of the time.
Reply:

Originally Posted by Hardsun1

William,I have to say, I was completely shocked that I received a response to my post, so let me start by saying thank you.I have had my machine for close to twenty years, and unfortunately was not able to use it for about the past 6 years at all. The machine in total is still much of a mystery to me in regards to the controls and settings, If I could pick your brain on those, I would be very appreciative. For the no spark/start issue I had, I removed the contactor, disassembled and cleaned all connections, removed the points (couldn't get a gap gauge .006 in between them) cleaned and gaped properly. Finally had no continuity from the torch to the power connection, replaced the power hose/cable. Now I have a spark and foot pedal control. I'm in the process of going through the machine and cleaning all connections and removing the corrosion that has accumulated. Regarding the controls, how best to adjust the "phase shift" and "intensity"?Again thanks for the response, I'm in a position to start using the great 'ol welder again, I really enjoy older well made tools. Much thanks,Julien Ramirez.
Reply:These are some pics of my machine, which needs cleaning badly.The spot gun timer and post purge are behind the nameplate.Harnischfeger is the name of the manufacturer and it says in the patent information it has something to do with Miller Electrical.



Sincerely, William McCormickIf I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.
Reply:

Originally Posted by zipzit

Yes, good suggestion.  I'm not really clear on what the post flow timer is actually doing.  The indicator spins, but it never really shuts off... I suspect there are some problems internally to that switch system.  We will take a look. In playing with this machine, I compare it to driving an old cadallic.. the ride is smooth, but it doesn't really accelerate quickly, doesn't brake all that well.. Its for just cruising down the road.  My inverter machine is like driving a go-kart with a 500hp engine.  Its really squirrely, difficult to control.  controlling the arc on the P&H is sorta tough to start (you have to have a VERY small gap, and it comes to life slow.. once there though it is very stable.)  The inverter starts pretty easily, but is much more touchy on the pedal.  The one thing I cannot do on the P&H is do a Tig Tack (high amperage setting, then quick bounce on the pedal once...)  No way, no how will the P&H do that.  You get zippo on a pedal bounce.  The Tig Tack (spot weld) is a nice tool to have in the arsenal.  Oh, well.  Anybody else been here before?thanks for your help,zipold machines used city water to cool the torch. ran it down the drain.So the water valve and gas valves were wired together.When using a cooler, do not use the water valve on any tig welder.Stopping the water flow can over heat and damage the procon pump.
Reply:I also own a P&H DAR 300 HFGW. I have used it as a stick welder (never TIG for about 30 years and yesterday the DC quit working. The AC works ok but when selecting DC straight or reversed polarity, There is no power at the electrode and the ground lead draws a lot of current when connected to a steel welding table. The return current must be going through the power cord ground as it gets quite warm.I am in need of a schematic as I suspect something has happened to part of the multi section Selenium rectifier stack.I would be happy to pay a fair price for the documentation. The ARMY tech manual is for a more modern machine is not helpful.Thanks in advanceDale R [email protected] 342 7726
Reply:I got one of these too. But BIGGER! Mines a 500 Amp. Are you getting or trying to get amperage from your torch attached to the gas out port?That only supplies gas. (on mine anyway) You need the adapter ring to connect the stinger to. Your amperage will come from the positive lead as if you were stick welding. Scratch start or turn your HF to start and get it close. mine will throw some small sparks for a second or two and then ignite the ark. It's probably easier to start with higher amperage but much harder to control. (I burnt through 1/4 inch plate in about 2 seconds cranked up to high...) (maybe it was only 3/16.) I only have about 10 minutes of experience doing this so don't take what I say as gospel, I'm just telling it as I see it. Oh and i don't have a pedal set up yet. I only have a finger dial  switch that seems to basically be an on off switch for whatever I have dialed in.
Reply:I am in need of a schematic as I suspect something has happened to part of the multi section Selenium rectifier stack.I would be happy to pay a fair price for the documentation. The ARMY tech manual is for a more modern machine is not helpful.Thanks in advanceDale R [email protected] 342 7726[/QUOTE]Sorry Dale, no dice here,gut I wanted to say that what you are saying sounds correct. Can't you just check for continuity between the diodes? you have it going one way  and not at all with the leads reversed. So if you have one section that goes both ways or more likely is just an open circuit you found your problem! Or something that needed replacing anyway...