Linde 250 Hf Troubleshooting

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Hello all,While this is my first time posting, I have been a lurker on this forum for a long time. I am able to weld oxy-acetylene, mig, tig, and stick in a ok manner, but not great. I learned everything through my school. I have just purchased my first welder. It is a Linde 250HF. I got it cheaply with the knowledge that it is not functional. I have already replaced an exploded capacitor on the (F/T) Filter Timer P.C. board. I would like to know if the problems I am having cam be attributed to one or more defective SCRs or SDRs, or something worse, like a fried transformer. My symptoms are as follow:>>I am unable to get any arc regardless of setting. Not even the slightest hint of a spark. >>When hooked up to power, the unit emits a transformer 'hum'. The sound doesn't change when I rotate the current selector switch from 'Off' to 'min 5A', 'min 35A' or 'min 70A' and it also doesn't change when I try to weld. (I have tried with both TIG and Stick setting)>>The Source power light isn't on when the welder is supplied with power.>>The 120v outlet on the front of the welder doesn't have any power when the welder is 'ON', or 'OFF' (It should always have power according to the instructions)>>The Welding power light doesn't turn on when I rotate the current selector away from 'OFF'>>All fuses on the panel test good>>The fan doesn't turn on when the current selector switch is rotated away from 'OFF'I have found a digital copy of the instruction booklet for a slightly newer version of the Linde 250HFhere.http://www.esab.ca/literature/Archiv...y_F-12-964.pdfNote that my welder has a 4 position current selector switch with one of the positions being 'OFF' while the welder in the PDF has a 3 position current selector switch and a separate toggle 'Ready--OFF' switch. Also I only have one 120V outlet, not two.Further notes:>>The welder is hooked up to a 240V kitchen stove circuit which is switched by two 120V 15amp breakers. (I know, not ideal, but I don't have access to anything better)>>The welder is set up for Single Phase power>>The remote switch is set to Stick when I had the foot pedal disconnected>>The current control potentiometer is not set to zero.>>The metal is bead-blasted 12 gauge mild steel sheet with the ground cable bolted to it.>>Even using 2' long sections of terminated battery cable as leads, i could not get any arc, so the is not the leads.>>The input terminal board is set up for 230V.Thanks for taking the time to read this and I look forward to any advice you have for me.
Reply:Do you have a volt / ohm meter?Lincoln SA200's... at least 15 - 20. They come and go. Growing partial to the "Short Hoods" in my old age. Last count on Short Hoods was 13 in possession.
Reply:I didn't have one this week past week, but I will borrow one by Monday. What should I be testing for when I get the multimeter?
Reply:Before you do anythig else the Linde like most has an AC input terminal strip where you can set the mach voltage to match the input voltage from the plug.  Usually next to where the power enters the mach. Make sure these are set right.  Next the input isl usually labeled L1,L2 or T1,T2, black to L1orT1 whtie to L2 or T2 and green to ground
Reply:When I first bought the machine, I changed the input voltage from 208V to 220V by moving the metal strips to the correct posts on the terminal strip. I have a 4 wire power cable with green being ground, red and black power and white (as neutral) not used and adequately insulated. I think that I have the power hooked up correctly.
Reply:With a 3 phase machine it usually runs, L1 black, L2 white, L3 red. if you hook is up wrong then it will not work, specificly if it is a single or 3 phase power supply.
Reply:Most HF are single phase white, black and green. drop the red unless you have 3 phase power to the shop then just make sure. In 220 white is not neutral it carries 110 v that is how you get 220 from 110.
Reply:I know that the white wire should be hooked up, not the red one, but the previous owner wired it up this way. I would change it to follow convention, however I am not going to because I would loose about a foot of my cable doing so. The white wire is cut shorter than the other 3 wires.
Reply:Then at least check each hot lead to ground to make sure you are getting 220 at the power supply.
Reply:I tested each hot lead to ground and got 120.6V and 121.1V respectfully. I am getting 207.5 between the two hot leads. I guess that it was properly wired up at 208V. The problem is not in the wiring between the machine and the outlet, but internal to the machine.
Reply:Sorry but you are reading 220/240 not 208 for one.  You have input voltage the next step is to see if it is getingt to the on/off switch and/ or if the switch is tranfering that power.
Reply:novajke this looks like it's gonna be one of those things where you need to understand some electronics.  Are you any good with electronics and also where are you? perhaps close to someone good at repairs. I'm no expert either but here goes my little bit of ??? But as I read this schmatic your main transformer being fed with 240 v has 2 secondaries. 1 for welding (so big conducters) with 80 volts (Left side of pic) and 1 120 volt that feeds the recepticle and pilot lamp and control circuits (right side of pic).Last edited by dumb as a stump; 10-01-2012 at 10:28 AM.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:So explain where the main power jumpers are. Termals what and what? Looking back I didn't see where you said what was jumpered exactly. because if all is correct and the power switch is on the light should work. next if the 10 amp fuse f3 is ok the recepticle should work. so I'm thinkin we are possibly not powered right. The previous owner may have had it wrong as well because he had problems with it too. Or transformer problems??? 1st things first can you meter that and reply?Last edited by dumb as a stump; 10-01-2012 at 10:43 AM.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Originally Posted by NovajkeI tested each hot lead to ground and got 120.6V and 121.1V respectfully. I am getting 207.5 between the two hot leads. I guess that it was properly wired up at 208V. The problem is not in the wiring between the machine and the outlet, but internal to the machine.
Reply:Originally Posted by Silicon-basedIt sounds like you have 120/208Y 3-phase power there. In that case it should be wired for 208V. If you're not sure, ask an electrician for help. You may damage the welder if you hook it up improperly.John
Reply:I see a couple of problems here. A standard kitchen stove here is USA needs at least a 50 amp 240 volt service.The breaker would be two 50 amp tied together with a bar. 15 amp breakers can only feed lights, no plugs.A standard 240 volt single phase house service should read 120 and 120 to ground or neutral. And 235 to 250 across the two hot. If you are getting only 207vac to the welder, you have a bad connection or an overloaded transformer. Or just to small of wire to carry the current, For safety it might be best to get an electrician out for an hour and see what is going on, Use the pretense  that you want to have him install a 50amp welder receptacle and you need a quote.Once you have good power we can look into your welder problem.
Reply:I am not an electrician, but I have repaired my share of old hifi stereo equipment. Last week, I couldn't test the circuits for continuity because I didn't have any equipment to do so. I got a high voltage multimeter today, but don't have much time. I was only able to measure the power reactor and the inductor of the machine. So far I have found that the high voltage side of the high frequency HVT is an open circuit, but this should not have any affect on the welders ability to make an arc if i have the HF off. It looks like the problem is somewhere around the 120v secondary transformer which powers the pilot lamp and control circuits, and outlet. I am living in an apartment complex built in the 1950's-1960's. Honestly, I couldn't read the current rating of the circuit breakers and they may in fact be 50 amp units. The panel is hidden behind the fridge and only has 4 circuit breakers on the panel, two of which are for the oven circuit. There is no way that the building is wired for more than one phase, so I may have misread the voltage readings, but either way the machine is properly wired for the voltage it is getting. (the power cable I am using is definitely beefy enough. I jumpered the pins on the board right at the input so it is set up for 230 V.Without the control circuits being powered up, it does make sense that the welder will not turn on the fan. Does it also make sense that the machine cant strike an arc?
Reply:So just to be clear you now have 2 jumpers on. 1 to 3 and 4 to 5 correct??? NOT like the picture. Also you meter 240 volts at L1 and L2 correct? Also you meter 80 at the big windings for welding ( at the left side) and NOT 120 at the other winding in the right side of the pic (in the manual you posted). Correct?Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:I just tested the resistance of the SCRs disconnected. For one I read 29.3 ohms both directions, and for the other I have 23.7 ohms or so both directions. The manual says that I should read a high resistance both ways, but I have no previous experience to judge whether they are good or not.I assume that they are fine, but want a second opinion.
Reply:Anode to cathode should read open. Gate to anode should be around 50 ohms or less.Gate to cathode should be open. May have this backwards.When measured with a standard volt / ohm meter.For the fan to turn on, you will need 240 volts to L1 and L2 and the voltage jumpers 1 to 3 and 4 to 5. F2 fuse must be good and the ready switch turned on.The pilot light should light up when the welder is plugged in and power is at L1 and L2.Could be burned out, look for 120 volt at light terminals.Look for 80vac at X1 and X2, 120 volts at X3 and X4, 24 vac at X5 and X6.None measured to case ground.Have to get to this point before worrying about the rest of the welder.
Reply:Yes, I have the correct jumpers installed. I haven't had the chance to have the unit hooked up to power again, so I didn't test voltage at any of the windings just yet, but I have no open circuits in the windings per resistance tests. (Horrah!)Never mind on the scr readings, I was testing from cathode to gate. I didn't disconnect the correct wires.My SCRs test good.
Reply:You are going to have to follow the problems down the line and forget the fact that you have arleady replaced any components and be careful with caps because they can store alot of power even after they are disconnected,Probably the best place to start is whether their are any open wiring in the transformer of if it is stepping power correctly,and how many taps if has, get a schematic, if you cant find one start writing one out for yourself and work it back till you have the pilot light working/
Reply:Thanks for all the great ideas on what to troubleshoot.Unfortunately I wont have a chance to look at this machine again until Friday.