fini Posted January 31, 2005 Author Share Posted January 31, 2005 Rich, Fluke has a top-notch website (www.fluke.com), where you could get a definitive answer. I was able to easily find the manual for mine. Or, you could call them: 1-888-99-FLUKE. So, another rule is to not measure current? I guess if you are not positive it's within a safe range, eh? It'd be fun to be able to come over to you guy's houses (promise to keep both hands in my pockets) and observe experienced electronics hobbyists at work... Or electronic Hobbits. Either one. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 31, 2005 Share Posted January 31, 2005 Rich, The larger cylinder under the battery is the fuse, labeled "F15A/600V" for the current function. The meter will operate in all the other functions if the 15A fuse blows as long as the battery is good. Also there is a resistor labeled " F63A just above it that may be a sort of fuse. http://forums.klipsch.com/idealbb/files/Fluke73.jpg Rick Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 31, 2005 Share Posted January 31, 2005 fini, If you use the meter to measure current, you have to place the meter IN the circuit. Not what many want to do. This means the current flows through the large fuse in the meter. Most use the method of measuring the voltage across a resistor of known value and calculating the current (using one of the variants of Ohm's Law. For example, my current (no pun intended) EL34 tubes now have a ten ohm resistor from cathode to ground. When I measure the voltage across the resistor, I should get .50 volts. Using Ohm's Law (you DID save that chart that Mark posted, right?), we want to know I (current). I=E/R, or current = voltage divided by resistance. So my .5 volts divided by 10 ohms give me .05 amps or 50 milliamps. It's a lot easier and a lot safer that opeing the cricuit and placing the meter in line. Both ways would work. Marvel Quote Link to comment Share on other sites More sharing options...
fini Posted January 31, 2005 Author Share Posted January 31, 2005 Marvel, Thank you for that example. It's quite clear. Yes, saved the chart as well as Clipped's resistor value chart. Actually, I printed out that whole thread! I'm getting pretty good at checking resistor values (gettin' my multimeter chops down before powering the amp). Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 31, 2005 Share Posted January 31, 2005 Cool! The more you make use of it, the less you will forget, and the more second nature it will become. Do you have a line on some caps for that power supply yet? Marvel Quote Link to comment Share on other sites More sharing options...
fini Posted January 31, 2005 Author Share Posted January 31, 2005 No, I haven't figured out what I need yet. I suppose changing out those "milk duds" are in order, but I haven't pulled that big cap under the chassis to see it's value (not sure how flexible the hookup wires are. I.E. they might break loose if I remove it from the bracket). Or are you refering to the can caps on top of the power amp? I could use some advice when it comes to quality vs. price for the parts. I don't want to go overboard, or hot-rod it, but I don't want to put junk in there, either. Quote Link to comment Share on other sites More sharing options...
Marvel Posted January 31, 2005 Share Posted January 31, 2005 I was thinking of this one: You can read the voltage rating for it and the cap value is probably easy to spot without moving it much. Just make sure it's discharged! Marvel Quote Link to comment Share on other sites More sharing options...
fini Posted January 31, 2005 Author Share Posted January 31, 2005 It hasn't been powered-up in a week. These things discharge pretty quickly, right? Someone had suggested the resistors on top were "bleeders." Otherwise, grounding the terminals to which the resistors are soldered would do the trick? Insulated wire, I know... Quote Link to comment Share on other sites More sharing options...
richinlr Posted February 1, 2005 Share Posted February 1, 2005 ---------------- On 1/31/2005 11:28:22 AM 3dzapper wrote: Rich, The larger cylinder under the battery is the fuse, labeled "F15A/600V" for the current function. The meter will operate in all the other functions if the 15A fuse blows as long as the battery is good. Also there is a resistor labeled " F63A just above it that may be a sort of fuse. Rick ---------------- fini, Thanks for the info - they don't have a manual for the 73 - fortunately I still have mine. Rick, Boy, is this interesting! Both the box and my meter are clearly labeled "Fluke 73 Multimeter". However, just as clearly as yours says "FUSED" on the current input, mine says "UNFUSED" in the same place and there is no fuse inside. There is, however a heavy guage stright jumper between the current input and common input (looks like a direct short to me)and it is intact. The book says that F1 (a 1K resistor adjacent to the back end of the battery) is fusible. However, it is not open and measures 1K. The meter has done nothing since the accident - won't even turn on. Quote Link to comment Share on other sites More sharing options...
fini Posted February 2, 2005 Author Share Posted February 2, 2005 In testing resistors, I'm finding quite a few that are well outside of tolerance (and some WAY out). I mean, I've got, maybe 15 or 20 of these little buggers that probably need changing (I guess). A question regarding resistor-swapping technique: Do I really need to desolder resistors (and by extension, everything else connected to each end), or could I snip the bad resistor leads long, bend them into an "eye", through which I'd slip the new resistor leads, then solder? Is this an accepted method, or is it too funky? Before I actually start changing parts, I'm going to do all the prescribed testing, but when the time comes to dig in, I'd sure like some guidance in terms of what to change first, when in the process to power it up, etc. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 2, 2005 Share Posted February 2, 2005 "A question regarding resistor-swapping technique: Do I really need to desolder resistors (and by extension, everything else connected to each end), or could I snip the bad resistor leads long, bend them into an "eye", through which I'd slip the new resistor leads, then solder? Is this an accepted method, or is it too funky?" I guess a guy can do that, but it's cheating. I've done it with resistors I wanted to use that had little or no leads left. Make little eyes with the leads, loop them through and solder. Keep in mind carbon composition resistors are temperature dependant, meaning that the values can drift with heat. They don't like moisture either. But if they are way off tolerance cold, I would assume you pretty much need to change them out. Quote Link to comment Share on other sites More sharing options...
fini Posted February 2, 2005 Author Share Posted February 2, 2005 This console definitely had no moisture issues. Not a speck of rust, nice. The bad resistors seem to be in clusters. In one case, 4 resistors had about the same measured values, although two were much higher and two much lower (according to the pretty stripes). I am fantasizing that there is a problem with the "big black" double cap (whose values are 40 uF @ 400VDC, and 20 uF @ 300 VDC), and somehow it ruined these resistors, and a few tubes. Is this possible, or likely? I'm not sure if I should fire it up and check those voltages Mark asked for at this point. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 2, 2005 Share Posted February 2, 2005 "I'm not sure if I should fire it up and check those voltages Mark asked for at this point." Just be carefull and go for it. Just follow Mark's post step by step. He explained it in a nice easy manner, I always admire that. I usually learn something from his posts, I did from that one. © This rich text is kinda cool....§♥¥♣ؼ½¾ξ ¿ Quote Link to comment Share on other sites More sharing options...
fini Posted February 3, 2005 Author Share Posted February 3, 2005 You know, cussing is still disallowed, even if done in some weird rich text language... So, I think i may be finding out these things I thought were resistors (the bad ones) might be axial lead capacitors. They have stripes, too. Why do they make this so confusing? I mean, aren't numbers a pretty much universal language? I agree about mark's clear language. Excellent. Oh, I got that replacement MK IV power transformer today, from forum member binkt (who's up your way, Mike). Super nice fellow (like you), also willing to help me with this. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 3, 2005 Share Posted February 3, 2005 "So, I think i may be finding out these things I thought were resistors (the bad ones) might be axial lead capacitors. They have stripes, too. Why do they make this so confusing? I mean, aren't numbers a pretty much universal language?" You would think so.... Type in a search for color code values for capacitors, you should find something. I thinks it's kinda the same as resistors, not too sure of that... "Oh, I got that replacement MK IV power transformer today, from forum member binkt (who's up your way, Mike). Super nice fellow (like you), also willing to help me with this." Cool! You get this stuff down, and you can go homebrew, and then you can put your woodworking talent to work. I still need to make little wood sides and fronts for the Maggotboxes, same for the 300B. Quote Link to comment Share on other sites More sharing options...
fini Posted February 3, 2005 Author Share Posted February 3, 2005 ---------------- On 2/3/2005 1:44:08 AM mike stehr wrote: I still need to make little wood sides and fronts for the Maggotboxes, same for the 300B. ---------------- Maybe I could do this for you? Shoot me some pictures and dimensions, and tell me what you're thinking. In keeping with the theme, I could make it out of recycled wood. Re: capacitor color codes. Yep, the same color code applies, but it seems more complex. As binkt advised last night, I need to make sure I know what's what before I start snippin'. I wish I had used the same cautionary proceedure when I attempted my own vasectomy. Aw, live and learn. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 3, 2005 Share Posted February 3, 2005 fini, for the most part older carbon resistors with the color code are brown, caps are black and have plastic looking enclosures. Don't bother to click on photo link. The forum ate my picture!! Rick Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 3, 2005 Share Posted February 3, 2005 Here it is!!! The cap is on the left. The cap is .047uF Resistor, 100K ohms Rick Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 3, 2005 Share Posted February 3, 2005 Oh yeah, If you want to desolder those old parts, get one of THESE. I don't use Dean's method of finger searing, solder braid. Rick Quote Link to comment Share on other sites More sharing options...
fini Posted February 3, 2005 Author Share Posted February 3, 2005 Rick, You'll be proud to know I bought Radio Shack's version of a solder sucker last week! I haven't tried it yet, but do these things really leave wires de-soldered to the point where you can just un-twist or un-wind them? Amazing! I'll post a few photos of the questionable innards once I get kiddies of to school... Quote Link to comment Share on other sites More sharing options...
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