Idealarc 250 & DryRod oven followed me home

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Here's last weeks local CL finds: a couple of fixer uppers that should clean up decently..Idealarc 250-250 AC/DC with factory cart  and power-factor capacitors: needs leads, maybe caps & diodes; strong AC output, straight body, rusty floor pan; $175code: 8645-Cserial #: AC-542016mfr date: 1982Testing this out was funny. The seller insisted he had leads for the machine. When I arrived I found several #4 leads vise-gripped together and to the machine. After running most of a stick on the 250a AC setting, the insulation started smoking. Fortunately the seller was up on the roof of his house, out of sight, when all of this was happening. The machine originally came out the rail yard shop in Missoula, Montana.    Phoenix DryRod rod oven , , Model 10 (discontinued), Type: 50A, Watts: 350: $30parts list at  http://www.phx-international.com/Type50APartsList_EC.pdfThis needs  a little clean up to remove some flash rust from the inside, and to get the concrete slop off the outside. How does a rod oven get concrete splashed on it?  ____________________Retro_shopLincoln V300 ProLincoln LN-25 w/ Tweco #4 gunCobramatic 150-003 w/ push-pull gunMiller Dynasty 200
Reply:$175 seems like a lot to pay for that machine without leads and only half working.  Rod oven is a deal if it worksTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:The oven works well. I agree the welder price is nothing special given its condition, but I already have a spare set of leads for it, and the caps and diodes should cost less than another $175 get it back to good-as-new output. These machines are few and far between out here, lately.____________________Retro_shopLincoln V300 ProLincoln LN-25 w/ Tweco #4 gunCobramatic 150-003 w/ push-pull gunMiller Dynasty 200
Reply:I've got some diodes but they all flow in the same direction no pos neg setup...  looks like they used several smaller capaciy diodes in those.    Like 4 per side. U could get by with 2 per side of larger ones... I am asking $20 each for the miler ones I have 275 amp, 250v.  They could work but you would have to add a plate to one side so u could install them backwards...Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Originally Posted by soutthpawI've got some diodes but they all flow in the same direction no pos neg setup...  looks like they used several smaller capaciy diodes in those.    Like 4 per side. U could get by with 2 per side of larger ones... I am asking $20 each for the miler ones I have 275 amp, 250v.  They could work but you would have to add a plate to one side so u could install them backwards...
Reply:Ok so 4 of the ones I have would be enough. 2 per sideTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:I've got a idealarc as well, I just purchased 4 250 amp 800 volt stud type diodes for it. A user by the name stroked 550 has don't the modification. Good luck!
Reply:Originally Posted by soutthpawOk so 4 of the ones I have would be enough. 2 per side
Reply:I'm unclear on what the critical value is when selecting the replacement diodes. Is it the amps or the voltage?This thread http://weldingweb.com/vbb/showthread.php?t=58681 indicates that the replacement solution used four, 150a 600v diodes, mounted on the existing heat sinks with only slight modifications.Is this the case where, as long as the amp values are the same, and the voltage is greater or equal to the original voltage, that any diode will do? For instances could I use four, 150a 1000v diodes in this welder?____________________Retro_shopLincoln V300 ProLincoln LN-25 w/ Tweco #4 gunCobramatic 150-003 w/ push-pull gunMiller Dynasty 200
Reply:Originally Posted by retro_shopI'm unclear on what the critical value is when selecting the replacement diodes. Is it the amps or the voltage?This thread http://weldingweb.com/vbb/showthread.php?t=58681 indicates that the replacement solution used four, 150a 600v diodes, mounted on the existing heat sinks with only slight modifications.Is this the case where, as long as the amp values are the same, and the voltage is greater or equal to the original voltage, that any diode will do? For instances could I use four, 150a 1000v diodes in this welder?
Reply:I took your picture and color enhanced it so that you can see what is what. All twelve diodes between one plate and its two straps are oriented the same. For the alternate plate and two straps, the twelve diodes will be reversed.Hope this clears it up a bit.Papa Attached ImagesLincoln Idealarc 250 (circa 1962)Lincoln Weldpak 155 w/Mig KitLincoln Squarewave TIG 175
Reply:I've been looking for that exact machine and have had little luck.
Reply:Originally Posted by papaharley03I took your picture and color enhanced it so that you can see what is what. All twelve diodes between one plate and its two straps are oriented the same. For the alternate plate and two straps, the twelve diodes will be reversed.Hope this clears it up a bit.Papa
Reply:Thanks papaharley03. The image coloration, an hour starring at the schematic and a review of diodes at Wikipedia has me a lot closer to figuring out how to mount the newer style diodes like stroker550's did. I now have the "cathode" and "anode" thing figured out.The generic part numbers for the 150a 600v diodes are:150KR60A: anode (+) on the post, aka "reversed"150K60A: anode (+) on the pigtail, aka "forward"I found the new style diodes on ebay for $62 total and they will save me a lot time by not having to solder 24 replacements.I'll post final results when I get the machine running again.Last edited by retro_shop; 09-15-2011 at 01:55 AM.____________________Retro_shopLincoln V300 ProLincoln LN-25 w/ Tweco #4 gunCobramatic 150-003 w/ push-pull gunMiller Dynasty 200
Reply:Originally Posted by retro_shopthey will save me a lot time by not having to solder 24 replacements.
Reply:Originally Posted by papaharley03Hehe... it all depends on your background, I guess. I'd rather unsolder/re-solder 24 diodes than drill large holes in the metal plates. Meaning, I feel more comfortable with a soldering iron in my hand.Good luck!Papa
Reply:Keep a damp sponge handy to wipe the soldering iron tip between passes. Some soldering stations even come with a cup for a sponge.
Reply:Originally Posted by soutthpawI'm with retro on that, I can't solder to save my life...    tips seem to start to ball up the solder after a few uses
Reply:To unsolder  the old diodes just use a propane torch to heat up the plates.You may even need to preheat the plates or you will never get the solder to melt with out over heating and damaging your new diodes. You want fast high heat to solder. then cool them down. On this board is a nice picture of a retro fitted diodes assembly the just required a few holes. easily done with a hole saw and a drill press.
Reply:My Idealarc 250 ac/dc is an '89 model, and when I bought it the leads were in terrible shape with bare wire showing in several places. I cleaned the bad places and taped them up, and have been welding with it, but it just doesn't seem to be welding as smooth as it should.I recently redone two splices on the leads that didn't look very good, and also cleaned up the lead terminals on the machine. I haven't tried the welder out since then, so I don't know if it welds better now or not. If it still doesn't seem right, I think I'll test the amp output at the terminals on the machine as Papaharley suggested to someone on another thread, and see what it's putting out.This thread has me wondering if it could be a diode problem, which I know nothing about.I'm wondering what the symptom's are when diodes go bad? I appreciate your help.
Reply:Originally Posted by eastexanIf it still doesn't seem right, I think I'll test the amp output at the terminals on the machine as Papaharley suggested to someone on another thread, and see what it's putting out.This thread has me wondering if it could be a diode problem, which I know nothing about.I'm wondering what the symptom's are when diodes go bad? I appreciate your help.