Dear knowledgable members,
I am at home during this crazy time with nothing but time and decided to expand my knowledge of trouble shooting and testing vintage amplifiers. This is something
I have repaired and spent a great deal of time building some amplifier kits, replacing caps in speakers, amps etc. This has all been done with much help from you guys in the past. Thank you.
My next step is to get a better understanding of electronics so I am not muddling my way through the process before I invest in test equipment, Oscilloscope, signal generator etc. I would like to be confident in my repair approach and I would love to be able to see how my amps are performing, watts rms for instance.
I am obviously a beginner and feel what I need is to have a greater understanding of the following.
1. How to read amplifier schematics
2. Oscilloscope grounding - floating ground - This really has me spooked even after watching many different videos on the subject, none of which has given me the confidence. I understand that most of my vintage gear is floating as they only have 2 pin plugs, but do I still need to hook my gear under test to an Isolation Transformer?
I am not necessarily looking for answers here, although that would be nice, but rather if anyone can direct me to decent resources that can help me.
One resource that I have found on Youtube is "xraytonyb". He does many videos on vintage repair/restoration and have found him to me very informative. The one thing which I find in all of these types of videos is the presenter does not show the exact locations of where they are hooking up test probes and leads.
Thanks you so much for any assistance any of you can give me.
Clive
I am at home during this crazy time with nothing but time and decided to expand my knowledge of trouble shooting and testing vintage amplifiers. This is something
I have repaired and spent a great deal of time building some amplifier kits, replacing caps in speakers, amps etc. This has all been done with much help from you guys in the past. Thank you.
My next step is to get a better understanding of electronics so I am not muddling my way through the process before I invest in test equipment, Oscilloscope, signal generator etc. I would like to be confident in my repair approach and I would love to be able to see how my amps are performing, watts rms for instance.
I am obviously a beginner and feel what I need is to have a greater understanding of the following.
1. How to read amplifier schematics
2. Oscilloscope grounding - floating ground - This really has me spooked even after watching many different videos on the subject, none of which has given me the confidence. I understand that most of my vintage gear is floating as they only have 2 pin plugs, but do I still need to hook my gear under test to an Isolation Transformer?
I am not necessarily looking for answers here, although that would be nice, but rather if anyone can direct me to decent resources that can help me.
One resource that I have found on Youtube is "xraytonyb". He does many videos on vintage repair/restoration and have found him to me very informative. The one thing which I find in all of these types of videos is the presenter does not show the exact locations of where they are hooking up test probes and leads.
Thanks you so much for any assistance any of you can give me.
Clive
In order to repair succesfully, you have defined yourself two conditions which you should master before engaging in your ambition.
Reading schematics is a result of proper education. There is no shorter route available yet.
Grounding is understanding that there is no 'grounding', as everything is relative actually.
Also this is a part of ElectroMagnetic Compatibility (say loud without error ten times).
One has to fold and wrap above in and around one's head.
Reading schematics is a result of proper education. There is no shorter route available yet.
Grounding is understanding that there is no 'grounding', as everything is relative actually.
Also this is a part of ElectroMagnetic Compatibility (say loud without error ten times).
One has to fold and wrap above in and around one's head.
Any equipment lacking a power transformer is inherently dangerous, and you should not work on it.
Floating a scope is also a bad idea in most cases, and dangerous, and only experts should attempt that.
However, having the proper probes eliminates any need for anyone to ever float a scope.
Any circuit with over 50V present is also dangerous to work on.
https://www.pearl-hifi.com/06_Lit_A...Vol_16/Sec_51/4420_The_Art_of_Electronics.pdf
Reading Schematics
How to Read a Schematic - learn.sparkfun.com
Floating a scope is also a bad idea in most cases, and dangerous, and only experts should attempt that.
However, having the proper probes eliminates any need for anyone to ever float a scope.
Any circuit with over 50V present is also dangerous to work on.
https://www.pearl-hifi.com/06_Lit_A...Vol_16/Sec_51/4420_The_Art_of_Electronics.pdf
Reading Schematics
How to Read a Schematic - learn.sparkfun.com
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IMHO, an isolation transformer is a must have for any electronic workbench. Also a Variac. You can add these devices to obtaining an oscilloscope and function generator.
They make oscilloscopes that look, feel and behave like hand-held DMMs. I have a Fluke 123 model, which I can connect anywhere in a circuit without fear of "grounding" some high voltage accidentally. One drawback is it's battery operated. The LCD waveform display isnt as nice as a "real" oscilloscope, but it can make measurements out of the box that you'd need fancy differential probes to do with "real", earth grounded BNC shell input scopes.
One approach to learning how to read schematics is by writing them. Take a point-to-point wired tube amplifier and "reverse engineer" it by creating a schematic diagram from looking at the parts and how they're connected. If you have (or can borrow) a unit that has a schematic, try to create one without looking at the OEM published one first - then check your work. Practice this through several units and you'll soon be able to see the diagrams in your head when looking at components connected to a tube socket. Then you can extend to transistor amplifiers and receivers - or maybe by then, you'll be fine, reading them fluently.
Best of luck in your endeavors!
They make oscilloscopes that look, feel and behave like hand-held DMMs. I have a Fluke 123 model, which I can connect anywhere in a circuit without fear of "grounding" some high voltage accidentally. One drawback is it's battery operated. The LCD waveform display isnt as nice as a "real" oscilloscope, but it can make measurements out of the box that you'd need fancy differential probes to do with "real", earth grounded BNC shell input scopes.
One approach to learning how to read schematics is by writing them. Take a point-to-point wired tube amplifier and "reverse engineer" it by creating a schematic diagram from looking at the parts and how they're connected. If you have (or can borrow) a unit that has a schematic, try to create one without looking at the OEM published one first - then check your work. Practice this through several units and you'll soon be able to see the diagrams in your head when looking at components connected to a tube socket. Then you can extend to transistor amplifiers and receivers - or maybe by then, you'll be fine, reading them fluently.
Best of luck in your endeavors!
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Thank you all!! You have confirmed a few things about my intended approach and then some, and for that I am grateful.
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