thebes Posted March 13, 2011 Share Posted March 13, 2011 Hey, what could possibly go wrong? I'm with you, Marty, but some guys are just sissies. Smart sissies. I didn't think you could test a transformer with just a multimeter. Can you? [/quote Not completly but you can sure do some basics. Think about it for a minute. Transformers are basically circular in nature. They have loops. Take an OPT with 4, 8, 16 ohm taps.Put a meter on each end of that particular tap, you will get a resistance reading. Move to another tap, the reading will be different. If they are all the same, uh oh. Then think about heater leads from a power transformer. Zero or little resistance across the leads means that particular circuit is intact. No reading, you got a broken or melted wire. I'm sure my tube Sensei, MikeBSE2A3, could explain it better but I'm sure he's busy recovering from the shock of realizing that I really was kinda paying attention to his lessons. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted March 14, 2011 Share Posted March 14, 2011 Many years ago I was troubleshooting the power diodes on the DC bridge of a 400 amp welder. The shop owner, an old timer to say the least, was watching over my shoulder. He loudly announced "It's got to make a circuit to do work". That's a good one to remember and he made sure it stayed with me. [] Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 14, 2011 Share Posted March 14, 2011 Many years ago I was troubleshooting the power diodes on the DC bridge of a 400 amp welder. The shop owner, an old timer to say the least, was watching over my shoulder. He loudly announced "It's got to make a circuit to do work". That's a good one to remember and he made sure it stayed with me. I worked at a boat trailer company in the manufacturing area. (presses, welders, punches, etc..) This one guy would usually work in the "Notcher" area. The Notcher was a couple Plasma cutters, set-up for cutting half circles on the ends of boxed steel tubing. After notching, the tubes are drilled and then formed on a brake. They are used for crossmembers or axles. Each Plasma cutter had it's own DC supply. (more or less a welder...) One night there is a little more smoke than the usual burnt ozone and metal from the cutter. The guy appears, and he's kinda frazzled looking. Being a good little chap, he wanted to blow out the DC supplies and keep his area clean. Nothing wrong with that. Except he stuck the the tube of the air nozzle inside the DC supply while in operation, and shorted the tube across a bank of larger resistors inside the supply...POOF!! Smoked the supply. Being a steel shop more or less, one always wears gloves and he was wearing some heavier leather ones, but he still got zinged a bit. You can always tell by how they act...like they just took big hit of crack or sumthin'... Quote Link to comment Share on other sites More sharing options...
HudsonValleyNoah Posted March 16, 2011 Share Posted March 16, 2011 Updates? Any more pictures? Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 16, 2011 Share Posted March 16, 2011 Testing output transformers with a multimeter is pretty difficult since most high quality output transformers have low DCR. You need an inductance meter, which will let you compare to predicable results. 16ohm has 4X the inductance of the 4ohm - ground tap, 8ohm has 2X inductance of the 4ohm - ground tap. Quote Link to comment Share on other sites More sharing options...
Ironsave Posted March 16, 2011 Share Posted March 16, 2011 Updates? Any more pictures? I missed this thread till now. Nice find; and I hope you get it restored to all its original beauty...... Can't wait to see the progress...... Thanks for the post! Quote Link to comment Share on other sites More sharing options...
Gilbert Posted March 18, 2011 Share Posted March 18, 2011 What happens when you plug her in? Yea, that's not going to happen for bit. Some measurements, couple parts replacement/upgrades and then on a variac. A real man would have plugged her right-in, straight away w/o any hesitation. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted March 18, 2011 Share Posted March 18, 2011 A real man would have plugged her right-in, straight away w/o any hesitation. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted March 18, 2011 Author Share Posted March 18, 2011 I guess you could say I'm old school. Yes the whole one hand in the pocket to keep the heart going and "don't let the magic smoke out." Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 25, 2011 Author Share Posted April 25, 2011 Time for an update. I finally got back to the amp this past weekend. I decided to do what I can with what I have and get the amp up and going. I may, at a later date, do a full blown rebuild and replace the chassis, but for now...bead blasting. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 25, 2011 Author Share Posted April 25, 2011 Next mask everthing off before paint Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 25, 2011 Author Share Posted April 25, 2011 Krylon primer done Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 25, 2011 Author Share Posted April 25, 2011 The painting is done. It is called dark red toriador. It is an automotive metalic acylic enamel. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 25, 2011 Author Share Posted April 25, 2011 Now to the inside where I need to repace some diodes and caps for safe operation. Quote Link to comment Share on other sites More sharing options...
Timmikid Posted April 27, 2011 Share Posted April 27, 2011 Fantastic project! Looking good man! Greetings, Tim. Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 27, 2011 Author Share Posted April 27, 2011 Fantastic project! Looking good man! Greetings, Tim. Hi Tim, nice to hear from you. How is life on the other side of the planet? Quote Link to comment Share on other sites More sharing options...
gnatnoop Posted April 27, 2011 Share Posted April 27, 2011 outstanding, love the color combo! Quote Link to comment Share on other sites More sharing options...
Wardsweb Posted April 29, 2011 Author Share Posted April 29, 2011 Not having a power switch to me is a PITA. So, I moved the fuse inside the chassis and installed a vintage push button power switch in its place. I figured if the fuse blows you should open it up anyway. That and the switch looks like it came that way. Quote Link to comment Share on other sites More sharing options...
Donkeyshins Posted April 29, 2011 Share Posted April 29, 2011 Not having a power switch to me is a PITA. So, I moved the fuse inside the chassis and installed a vintage push button power switch in its place. I figured if the fuse blows you should open it up anyway. That and the switch looks like it came that way. Purity be damned. I think that's the nicest looking MC240 I've ever seen. I love the red! Now all you need is some nice Russian K40Y PIO caps. -D Quote Link to comment Share on other sites More sharing options...
Boxx Posted April 29, 2011 Share Posted April 29, 2011 I am very impressed... Outstanding, my friend.... Quote Link to comment Share on other sites More sharing options...
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