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Introduction

oldguy

New Member
Hi all, Hope I am in the right place. I am an older retired guy looking to repair vintage stereo equipment as a hobby. I am looking for advise on such things as testing equipment and such. I do not have deep pockets and live on a fixed income.
See you there..

old guy
 

JimB

Super Moderator
Most Helpful Member
Hello there.
Lots of old guys here on ETO, including me. Don't be fooled by the avatar picture.

I am looking for advise on such things as testing equipment and such.
As a bare minimum:

Hand tools, ie screwdrivers, pliers, cutters.
A few spanners, or an adjustable spanner for removing the nuts from panel mounted controls.

A decent soldering iron and some solder. The solder should be 60/40 tin/lead (or 63/37 tin lead). Lead free solder can be a real pain, try to avoid it.

A multimeter. Digital multimeters come in a wide range of capabilities and prices.
Some of the simpler/cheaper ones are very good value.

JimB
 

RadioRon

Well-Known Member
A cheap LCR meter ($25 on ebay) is very useful for checking old capacitors.
I agree with Jim that a good soldering iron is your second priority after some key hand tools. I like products from Hakko myself.

An oscilloscope is a very useful item, but probably a bit too expensive for you right now. You can do quite a bit of repair without one as many problems in old stereos are bad controls and pots, bad capacitors and bad connections. A scope isn't needed for these most of the time. Depending on your budget, you can get a brand new scope for $299 (ie. Rigol DS1102E), and used ones for less than $200.

I would prefer a simple scope over spending any money on a logic probe or other simpler devices, with one exception. In my early days I got a lot of use out of an RF/AF Signal Tracer. Mine was an old HeathKit unit which is museum stuff now, but since this type of thing is nothing more than a high gain audio amp with a high impedance input, a switchable detector diode, a speaker and meter on the output and a battery for power, you can build your own or buy a kit for very little. Google RF Signal Tracer for DIY plans. This is much better value than a scope if the funds are really tight.

At first, I think it unlikely that you need a signal generator since you can probably pick up signals off the air for checking receivers. However, in case you might consider it later on, there are many very good used ones out there that cost more than $300, but these are overkill for what you might need. Perhaps you can find on older Leader or B&K, or Instek, or something like that in the $50 range.

As Jim was suggesting, good hand tools are pretty important at the start and while you didn't ask specifically about this category, its worth your attention. You need a few basic but very good quality items including small wire cutters, tweezers and needle nose pliers. Fixing old stereos involves taking great care not to scratch panels or lose screws while you are working on them, so set up a good workspace with a soft surface on the bench, with nearby cleaning supplies like paper towels, a bottle of isopropyl alcohol (buy cheap at Costco), perhaps an alcohol dispenser, For small parts, perhaps consider a muffin pan or the like so things don't get lost. Sometimes a little magnetic pan like mechanics use can be good to hold screws. Its also worth mentioning that you need some sort of very good lamp on your bench, perhaps a simple gooseneck lamp with LED bulb or something like that, because you will need some good light to see inside the box you are working on and a flashlight just doesn't cut it. Of course you need screwdrivers and you'll probably have to invest in a set of micro-sized ones, like so-called jewelers screwdrivers or repair sets for laptops. Lots of these on ebay and elsewhere for only a couple of dollars.

Are you going to focus on cosmetic restoration at all? Perhaps you will need to learn about how to refinish a wood panel, or how to polish scratches out of a clear plastic part. At the very least, basic cleaning is required and while I like Isopropyl Alcohol (99%) for this, there are lots of detergents and household cleaners that may be useful. Removing dust is always necessary and a small vacuum cleaner is useful for this. Also, some compressed air for blowing dirt out of a chassis is really handy too. A small compressor is another big ticket item, but very handy for blowing things clean.
 

oldguy

New Member
Hi guys thanks for your replies. I suppose at this point a very brief personal background would be very useful. I have spent nearly 50 years repairing every kind of equipment you can imagine. I was educated as an aircraft mechanic, completed mechanical engineering degree,
went half way through engineering electronics degree before switching to mechanical. My career was as a manufacturing engineer and product design engineer. I have repaired almost any kind of manufacturing equipment there is such as industrial lasers and cnc machining centers.
My short comings at least in the beginning is going to be circuit analysis (audio circuits), selecting components for replacement ie different types of capacitors and basic troubleshooting of audio circuits.
I have a fluk meter and more than one roll away full of hand tools. Not sure what types of scopes, testers would be necessary.

Again thanks so much for your replies.
 

unclejed613

Well-Known Member
Most Helpful Member
for audio work a 30Mhz bandwidth scope is sufficient, but it's nice to have a 100 or 200Mhz scope, and even those aren't very expensive these days. you also might want to get a distortion analyzer and a noise meter. a spectrum analyzer with 100khz bandwidth is also useful. you will want to have non-inductive load resistors (8 ohm @ a minimum of 100 watts). i used to use a Variac to slowly bring up the voltage after a repair, but have found putting an incandescent bulb (i use 50W bulbs for low power amplifiers, and 100 and 200W for big amplifiers) in series as a current limiter more useful. a function generator is ok for most testing, but you need a very low distortion oscillator for doing distortion measurements (a good distortion analyzer will have one built in). if you plan on repairing receivers, an RF generator with AM and FM modulation can be useful for alignment. you will want to have a signal generator capable of FM stereo if you plan on aligning FM tuners (or a multiplex audio generator that can be fed into the FM input of an RF generator). if you plan on repairing vacuum tube equipment, a tube tester (specifically one that tests Gm and not just cathode emission) is an important piece of equipment. for solid state equipment, having a transistor that measures beta is helpful, because many amplifiers used beta matched output transistors.
 

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