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Require Equipment for repair Tube Equipment

Thanks for all the advice so far.
I have a Hakko FM-203, and the 2 pencils I use is rated at 70W and 140W so I think I am good on that part, but definitely I need a bigger tip for dealing with these thing.
I also picked up a TV-7 tube tester a while ago that someone refurbished for me (he changed a cap, tested the tube inside, and matched the reading with his Triplett 344 or something like that) so that sure will come in handy.
My DMM is a Fluke 87V, I am not sure if it can read or serve as a a capacitor tester or not. If not I can find one or buy the Mega 328 someone suggested.
Now the oscilloscope and the signal generator, I am not quite sure what brand to buy, or vintage or modern equipment etc... so may need to look around and see. I assume that the oscilloscope is used to match the signal with the original source to make sure that the specific part of the circuit is working properly?????
I will definitely build the dimb bulb tester. I have seen them on the web before and they seem simple enough. The dummy load can I just use a resistor with that value and rated to 100W?????
for_p1 said:
Real time spectrum and distortion analyzer.
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This is the one that I am a bit confused about, what does it do and what can I use it for?
Once again, thanks everyone for the great information. I am quite busy at the time so probably won't get into repairing them yet, but I would like to prepared so definitely those Youtube channels and books will come in handy!!!!!!!
 
for_p1 said:
Dummy loads from 2 to 16 ohms rated for 100W
Oscilloscope with high voltage (CAT IV) probes
RLC meter
Low distortion signal generator (should also provide test signals for IMD measurements)
Real time spectrum and distortion analyzer.
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I am sorry, what is the RLC meter?????
 
DraKnight13 said:
This is the one that I am a bit confused about, what does it do and what can I use it for?
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Its a cool tool if you want to do full distortion spectrum analysis, but certainly not necessary to restore things to normal working order. Thats more one of the advanced cool things you can play with if you're doing from-scratch design or extensive re-design work.

DraKnight13 said:
I am sorry, what is the RLC meter?????
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Resistor inductor Capacitor meter. For reasons I do not know, the usual schematic symbol for a choke is L, so RLC. It just tells you the value of those parts.

For an audio generator, you want something that will do at least 20 hz to 20khz, but if it will do at least 100khz, so much the better. The lower the distortion the better. If you're using a distortion meter that does not have an internal generator, having a low distortion source is critical so you can measure how much the amplifier is adding. If not, you want something that at least puts out a signal that looks like a sine wave so you can visually see if its getting mangled somewhere along the way. THere are some recent threads on scopes, I'd refer you there for some discussion on the merits of new vs old.

I would just like to point out that you don't need a full engineering lab to make a tube amp work again. Yes, having some advanced test gear can tell you things that basic stuff will not, but basic stuff will get you most of the way there. A soldering iron, a multimeter, and understanding of both will get you very far.
 
gadget73 said:
I would just like to point out that you don't need a full engineering lab to make a tube amp work again. Yes, having some advanced test gear can tell you things that basic stuff will not, but basic stuff will get you most of the way there. A soldering iron, a multimeter, and understanding of both will get you very far.
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That's a good quote
 
There's all kinds of cool equipment- instead of fixing stuff, you could become an equipment collector like me! Seriously, your learning curve should be ahead of your equipment acquisition curve. You should understand why you need a given thing before getting it. You'll make smarter decisions that way. Oddly, as I've traveled this path, a pattern showed up. First, I'd be convinced that if only I had some wonderful piece of test equipment, it would be way easier to fix something. Then, eventually, I got it. It might help but often not as much as I had hoped. Usually it led to wanting yet something else. But I learned a lot. More knowledge led to needing less test equipment. Troubleshooting is a mind game, not a contact sport. You should start out with the basics, good iron and bench tools, scope and sig gen, dummy loads and of course a couple DVMs. After that, you'll know when you need something else because it will be obvious.
 
gadget73 said:
Its a cool tool if you want to do full distortion spectrum analysis, but certainly not necessary to restore things to normal working order. Thats more one of the advanced cool things you can play with if you're doing from-scratch design or extensive re-design work.
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There is a difference between make amplifier "sorta work" and "work as designed". Distortion/spectrum analyzer is a must for second option.
 
ConradH said:
More knowledge led to needing less test equipment. Troubleshooting is a mind game, not a contact sport. You should start out with the basics, good iron and bench tools, scope and sig gen, dummy loads and of course a couple DVMs. After that, you'll know when you need something else because it will be obvious.
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:thumbsup:
 
I am a bit occupied at of the moment but will get to reading before getting my hand dirty with the actual work. Right now I think I have narrow the list down to the these that I have to get:
  • Dim Bulb
  • Oscilloscope
  • The signal generator and spectrum analyzer
  • the RLC meter (it would be great if someone can link me to an example so I know what to look for?)

Omegaman said:
Chopsticks to tap on tubes to check for harmonics
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I have heard these multiple time, but something about tapping a tube on a running amplifier scare me so I have not tried that yet. And I am not quite sure what I should look for?
 
I have heard these multiple time, but something about tapping a tube on a running amplifier scare me so I have not tried that yet. And I am not quite sure what I should look for?
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Some tubes are "microphonic"...if you tap on the glass or on the nearby chassis, you'll hear the tapping through the speakers.
6dj8 is a tube prone to being microphonic. I prefer to use the military variants (6dj8=6922=7308) whenever possible to minimize microphonic's. Usually the military versions have extra support rods or extra mica's to make them sturdier. JAN (Joint Army Navy) tubes are designed for the military.

Personally, if you're just starting out I think you can get by without an oscilloscope or spectrum analyzer.
Sencore LC75 is the capacitor tester I have, I bought it used and calibrated for a few hundred bucks years ago and I always use it.
O-scope is great if you NEED it. The only time I needed one was when I calibrated my tube tester's internal rectifier tube for DC balance. Otherwise, for general amp/preamp repair I've gotten along fine with a few DMM's. A dual trace O-scope can show you if there is AC riding on the DC or vice versa. An O-scope does a better job of measuring voltages than a DMM, but I don't think it's worth the expense for general repair.
 
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