Learning to Recap / Restore Vintage Receivers

[Treker]

Over the past year or so that I have been into collecting vintage audio gear as a hobby, I have been thinking about what it would take to learn how to recap and restore some of the vintage receivers I have acquired.

Now, I don’t have any background or experience in electronics per se, but I am a fairly intelligent person and feel I could learn how to do it myself. I am also very mechanically inclined, so I am not afraid to dig into this stuff. I have been building and repairing things since I was a kid, with most of my most recent experience being in the area of building radio controlled model airplanes. I also have already completed a re-lamp and DeOxit treatment of my Marantz 2238B receiver that turned out well.

I am certain there are people here on AudioKarma that are self-taught, as well as people who learned about electronics repair either in a school of some sort or in a professional setting. What I am interested in doing is learning from your combined knowledge and experience and learning how to do this type of work for myself. I love to learn new things, as I find the challenge fun, and I find great pleasure in mastering a new skill or area of knowledge. Seeing the finished product and knowing that it is the result of your handiwork is also a great source of pleasure.

What I am really wondering is just what the best way to go about doing this is. I have looked around the AudioKarma web site for a tutorial on recapping, (maybe I haven’t looked hard enough) but so far I have not found one. Does anyone know of either on online tutorial, or possibly a good book on basic electronics repair? What I am looking for (I think) is something to help me learn the basic skills I will need to complete a recap / restoration of a vintage solid state receiver.

Here are some of my thoughts on how I plan to proceed:

First of all, I will need to gather the necessary tools and materials to do the job. So far my list includes the following, although I suspect I am leaving things out:

1) Soldering iron of the proper size and type (Which brand(s) or model(s) would be appropriate? Where is a good place to get one?)
2) Solder of the proper type (Which type(s), styles(s), and or brand(s) are appropriate for working on vintage electronics? Where would I get one?)
3) Wire-Wrap de-soldering iron (Where would I get one?)
4) De-Soldering tool (Solder Sucker? Where would I get one?)
5) Service Manual and schematic for the receiver I will be repairing / restoring.
6) Electronic test equipment to check my work and allow me to make adjustments. (What kinds / types are absolutely necessary, and which ones are nice to have? I currently have a small, portable, Radio Shack multi-meter.)
7) Replacement parts for the unit I will be working on (replacement caps, resistors, lamps, etc. Good sources for ordering?)

First of all, I think I will need some practice, so I plan to start off slow. I currently have a dead (no sound) Technics SA-104 (early ‘80’s vintage) receiver that I thought I would use to practice leaning my de-soldering / soldering skills on. Who knows, I may even be able to bring this unit back to life, but that is not specifically my goal. My goal is to learn (hopefully) some of the basic diagnostic and repair skills that will help me in later projects. If I ruin this unit long the way, it is not a big loss.

Depending on how things go with the SA-104, my plan would be to next move up to one of my other vintage units, say my dead Technics SA-222 (another early ‘80’s vintage unit), or possibly my Kenwood KR-720 (yet another early ‘80’s vintage unit, but not dead), or my Marantz 2220. I personally would like to do the Marantz, but I also don’t want to ruin it. It is not currently dead, and I would rather it not end up that way.

If all goes well with my second unit, and I feel my skills and knowledge are up to the task, I would then move on to the units I really want to restore, and those are my Marantz 2220 (if I haven’t done it already), 2238B and 2250B receivers.

Thoughts anyone? I patiently await the vast knowledge and experience of the great Audio Karma community.

 

[SoCal Sam]

...First of all, I will need to gather the necessary tools and materials to do the job. So far my list includes the following, although I suspect I am leaving things out:

1) Soldering iron of the proper size and type (Which brand(s) or model(s) would be appropriate? Where is a good place to get one?)
2) Solder of the proper type (Which type(s), styles(s), and or brand(s) are appropriate for working on vintage electronics? Where would I get one?)
3) Wire-Wrap de-soldering iron (Where would I get one?)
4) De-Soldering tool (Solder Sucker? Where would I get one?)
5) Service Manual and schematic for the receiver I will be repairing / restoring.
6) Electronic test equipment to check my work and allow me to make adjustments. (What kinds / types are absolutely necessary, and which ones are nice to have? I currently have a small, portable, Radio Shack multi-meter.)
7) Replacement parts for the unit I will be working on (replacement caps, resistors, lamps, etc. Good sources for ordering?)...

I've always wanted to repair/restore ss but I got into tubes instead. However, the tools are much the same. I'll get us started...

1. Hakko 936 soldering station. Accept no substitutes. This is the professional's choice and is worth it for the amateur (you and me).
2. For tubes, I like .05 inch solder. A little thick for PCB's but great for point to point.
3. and 4. Check out the Hakko 808. I think there was a group buy here not too ago. I don't have one but some swear by them. I use wick and I should use a shovel attachment and a second 936 but I don't.
5. Many, many on-line resources. Most can be found for free.
6. DVM with capacitor tester for starters.
7. Digikey, Mouser, AES, your local e-surplus warehouse.

 

[Fun2Learn]

Read this thread

I am in much the same position you are in. I came here
to learn and so far have learned a lot.

I don't think anyone on these boards commands any higher
respect than EchoWars, both for his posts and for the work
he has done for members on these boards.

Here is a post of his that is a sticky in the DIY forum.

"So You Want To Repair Audio gear, Eh? Here's the tools you need..."


Good Luck!

 

[djwhy60]

In the same boat....but looking to do restores on my older tube stuff. I also have a 2220 that could use a good once over...like yours she plays well and don't want to trash it by jumping right in. Thanks for the post!

 

[RedFuneral]

Same here. I'd like to restore my S-6000 but I really have 0 experience soldering. I'm probably going to practice on my easily replaceable S-7210 that needs work and the SX-780 I got from a neighbor that needs quite a bit of work. I'll be watching this thread though I don't have anything I can contribute unfortunately.

Are things like an oscilloscope really necessary for recapping and other basic services? The price of that alone would put me over the cost of going to a technician and I only really need to restore this one amp.

 

[fernarias]

First read this for gear:

http://www.audiokarma.org/forums/showthread.php?t=333423

then buy a hakko 888 and 808.

Open up your 2220 and realized that it's going to be easy to work on and then open up any of the 80s gear and realize that it's not.
Practice soldering.
Download and print a service manual (just downloading will not help) and then read it (the 2220 has a very well put together service manual that not all units have).
Do a search on this forum for the 2220 and see what comes up (recap list may be available but you still need to check your unit carefully).
Decide on what caps to use (Panasonic FC/FM for everything would be the easiest but you might want to use KL/PW or use some fancy gold colored audio caps, etc.)
Learn about transistor orientation EBC vs CBE, etc., how to test them and then create matching pairs.
Start a "recapping a 2220" thread in the Marantz forum and take lots of pictures of each board before you start in case you mess up (mark the negative marks on the old capacitor with a black pen so that they show up in the pictures).
I usually start working on the power supply first (since it's the most important) and set it to spec, then the amp section and then the preamp.
You will need to replace some 2sc458 transistors because they get noisy and some diodes on the phone board(search is your friend).
Do one board at a time and start it up with a dim bulb tester (use search for dim bulb tester) since if it stops working you know which board the problem is on.
Clean the boards and the insides of your unit as you go.
Post pictures of your finished project.
Have fun and enjoy the improvement.

Then start the process again on your 2250B (2238B will be harder to do).

 

[CohibaJoe]

I am in much the same position you are in. I came here
to learn and so far have learned a lot.

I don't think anyone on these boards commands any higher
respect than EchoWars, both for his posts and for the work
he has done for members on these boards.

Here is a post of his that is a sticky in the DIY forum.

"So You Want To Repair Audio gear, Eh? Here's the tools you need..."


Good Luck!

I would also include Terry DeWick. Terry did a complete Restore on my MAC 1900. I also have asked question on another MAC 1900 I am working on and Terry answered my questions.

 

[Alienz]

There are some good soldering tutorials on youtube, helped me a lot.

 

[Sam Cogley]

1. Hakko 936 soldering station. Accept no substitutes. This is the professional's choice and is worth it for the amateur (you and me).

Several years ago I bought a rehabbed Hakko 926esd. It's a very nice machine, and Hakko is excellent about supporting their older equipment. They even came out with an improved line of tips for the stations using the same iron as the 926, even though it's been obsolete for years.

 

[Snerp]

As far as soldering irons go, I just use a radio shack 15w. I need to pick up one that will let me select the wattage, but if you know what you're doing any wattage will work.

I started my soldering career with micro soldering. I was replacing fuses in Nintendo DS lites with two solder points within the area of a pin head. After learning on the hard stuff, stereo soldering is a walk in the park. I would suggest you find an old motherboard and practice desoldering and soldering components.

 

[r_deming]

Same here! I started simply by recapping a tube amp from a motorola console. There were only 8 capacitors, so it really was pretty simple. That has given me a little confidence to try a solid state receiver my sister is giving me(early fisher SS). I have found a great local electronics place with reasonable prices:Orvac electronics in Fullerton. I also found a terrible parts place, but at least they are expensive and rude!

 

[Treker]

I am in much the same position you are in. I came here
to learn and so far have learned a lot.

I don't think anyone on these boards commands any higher
respect than EchoWars, both for his posts and for the work
he has done for members on these boards.

Here is a post of his that is a sticky in the DIY forum.

"So You Want To Repair Audio gear, Eh? Here's the tools you need..."


Good Luck!

Thanks for sharing the link to EchoWars' thread over in the FYI forum. I hadn't thought of looking over there. It contains a LOT of very helpful information, and was exactly the type of thread I was looking for. I knew the AK community would come through!

 

[ChrisMarantz]

I would suggest that one of the best ways to learn about electronics is to become exposed to as many different aspects of electronics as you have time for.

Not everyone needs to learn "from the beginning", you certainly can jump into the middle of something and work in both directions to learn about it. Remember that we all learn more from our failures than we do from our successes.

You could subscribe to the EEV Blog and watch Dave's videos from the beginning. While some of what he talks about is unrelated to anything you may ever do with vintage audio, many of the topics will apply and it will help you think about electronics in different ways. It will also help peak your interest in different topics, which will lead you in new directions and new things to learn about.

The most important aspect is to keep at it. It usually takes at least 2 years for anyone to started getting good at anything new. To many people quit before the 2 years is up and they never really excel in their venture.

Best of luck with your journey

 

[HVHiFI]

My $0.2. There is a TON on info on this site and many service manuals are available for download free. Learning to solder and desoldering is of course very important, and as suggested a Hakko 808, and 888 is an excellent setup but does run a few $$$. If you can't swing the 808 desoldering bulbs and suckers are an ok alternative. I prefer kestex "44" solder. Good hand tools are nice especially pliers, wire strippers, screwdrivers. A good DMM is clutch with auto-ranging, capacitance, diode functions are nice. You can get a descent one for $50-75. Build a dim bulb tester and a dummy load. A good o-scope to me in invaluable. You may get away without one for awhile but to really "see" what is going on you will eventually want one.

Getting into repairing vintage gear is not a cheap task. I found early on you get what you pay for with tools and test equipment. Some cheaper tools will do the job but not efficiently which being a hobbyist is not a big deal.

Ask lots of questions and make threads of your projects. Good luck!

 

[Bob]

couple of items

Find a kit of assorted caps. Panasonic used to have a set from
small to large values .01 to 2.2ufd in various voltages. Check with
Mouser or digikey both have sets from the cap mfg they sell.

Same for resistors. Start with metal film assortments in 1/4
and 1/2 watts. This will last a long time.

Suggest you get alligator clips to build your own test cables
and to use as a heat sink when desoldering transistors and such.

also, if you have old portable radios, amps, and speakers around
these make very good test equipment. add clips to the amp/radio
inputs, attach speakers and now you can clip to a test point to
trace audio signals.

Have a portable cd player with a headphone cable plugged in -
the other end strip the mini-plug and attach clips now you
can inject audio into the dead units to trace where the
problem areas are.

and if you are testing receivers and power amps, have a cheap
set of speakers with cables to attach when you test them.

Lastly, as someone mentiond do try to find schematics -
you can waste a lot of time tracing circuits.

A note about fixing things, you can sometimes use the
good channel to troubleshoot the bad channel. or use two
receivers to cross feed signals (pre-amp out of one to
power amp in of the other - although you could use the
portable CD player to do this).

good luck

Bob

 

[slowpat]

Treker - I just came across this thread. I know it's a 3 year old thread, but how is your effort in repairing/restoring vintage gear coming along? One tool you will need is a Dim Bulb Tester, and Markthefixer had a good write up on it in the Pioneer forum. As you progress, an Oscilloscope comes in handy.

 

[whopintp]

Treker - I just came across this thread. I know it's a 3 year old thread, but how is your effort in repairing/restoring vintage gear coming along? One tool you will need is a Dim Bulb Tester, and Markthefixer had a good write up on it in the Pioneer forum. As you progress, an Oscilloscope comes in handy.

So did I 2day. I worked at Telex Comm.for 6 yrs as a wireless tech. Worked my way up
to Customer Service. That's where my soldering skills REALLY came into play. When you
worked on newer transmitters W/surface mount. What a test.
Forward 11yrs later & B 4 I tackled my STA-2100, I started with Speaker Crossovers. I did
about 17-20 pair, & they were hard. Using caps bigger than the whole crossover( Like
the Infinity RS 3000). Then about a week ago, I looked at the amp & thought Damn I
have 10 times more room than the crossovers. W/schematics in hand, It WAS a lot
easier.

 

[Tom B]

A suggestion I would have is to read up on basic electronics theory. I have been repairing/troubleshooting for many years, and still rely upon the Basic Electronics skills I learned in tech school in the Air Force (1969).
Now I don't suggest you join the AF to learn this, but is very important to understand the underlying principals of Ohms law, voltage, current, power, resistance, capacitance, and Inductance, if you are going to work on electronics gear. Understanding the basics helps you to troubleshoot the problem better, and helps prevent compounding an existing problem.
There are many Internet based learning sites that have a lot of great info on "Basic Electronics" I feel it best to understand how things work, before just going in to replace things to try and get it working, if you know what I mean.
I always troubleshoot with an analog ohm meter (power off), and a digital voltmeter (Power on), before replacing anything. And the results of the testing usually point to why certain components failed, and other components that could be damaged. With solid state repair, it is imperitive to find "all" of the bad components, before attempting power up, to keep from blowing the replacement parts you may have put in. And of course the dim bulb tester, or variac should always be used for initial power up after working on any problem in a solid state unit especially any "Amplifier problem" or a Power Supply problem.

 

[slowpat]

A suggestion I would have is to read up on basic electronics theory. I have been repairing/troubleshooting for many years, and still rely upon the Basic Electronics skills I learned in tech school in the Air Force (1969).
Now I don't suggest you join the AF to learn this, but is very important to understand the underlying principals of Ohms law, voltage, current, power, resistance, capacitance, and Inductance, if you are going to work on electronics gear. Understanding the basics helps you to troubleshoot the problem better, and helps prevent compounding an existing problem.
There are many Internet based learning sites that have a lot of great info on "Basic Electronics" I feel it best to understand how things work, before just going in to replace things to try and get it working, if you know what I mean.
I always troubleshoot with an analog ohm meter (power off), and a digital voltmeter (Power on), before replacing anything. And the results of the testing usually point to why certain components failed, and other components that could be damaged. With solid state repair, it is imperitive to find "all" of the bad components, before attempting power up, to keep from blowing the replacement parts you may have put in. And of course the dim bulb tester, or variac should always be used for initial power up after working on any problem in a solid state unit especially any "Amplifier problem" or a Power Supply problem.

Wise words. That is the common theme I am seeing in advice from the techs, that you cannot skip understanding the fundamentals of electronics before understanding what you're doing to your gear. Shotgun replacement and asking for advice on forums with each step only goes so far.

 

[mars_volta]

If it ain't broke, don't fix it. Recapping and replacing working components is over rated IMO and introduces a lot of risk even to experienced techs. Spray the pots, clean it up, replace the lamps. Enjoy!

That said,

Working on something that has problems or is doa, I always try to start with a schematic and check the power supplies right away.