Learning about Solid State Amp repair. Where to start?

A

Audioduck

New Member
As always, apologies if this has already been discussed but do any of you know of a gentle way into troubleshooting and repairing Solid State Amps?

I have a lovely old Sansui, a NAD and a Rogers that I'd like to get off the shelf and back into use, each displaying different problems, but most of all, my trusty (and knackered) old Mission Cyrus 1 has just started making funny noises.

I know that I could replace all of these for not much money but I've been using them all of my listening life and I can't bear to part with them. They're MY amps.

Getting them repaired by a pro gives me two problems: 1.) I don't want anybody treating them like "knackered old amps" and fitting the cheapest components, and 2.) getting them repaired at £75.00 per hour just isn't economically viable.

And I want to learn how to do it.

Any ideas? Any classic texts on the subject?

M.
 
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Audioduck said:
As always, apologies if this has already been discussed but do any of you know of a gentle way into troubleshooting and repairing Solid State Amps?

I have a lovely old Sansui, a NAD and a Rogers that I'd like to get off the shelf and back into use, each displaying different problems, but most of all, my trusty (and knackered) old Mission Cyrus 1 has just started making funny noises.

I know that I could replace all of these for not much money but I've been using them all of my listening life and I can't bear to part with them. They're MY amps.

Getting them repaired by a pro gives me two problems: 1.) I don't want anybody treating them like "knackered old amps" and fitting the cheapest components, and 2.) getting them repaired at £75.00 per hour just isn't economically viable.

And I want to learn how to do it.

Any ideas? Any classic texts on the subject?

M.
Click to expand...

You need to have a reasonable amount of knowledge about electrical circuit and basic electronics. I will not proceed until I can locate a copy of the service manual (not just the user or instruction). I will try the manufacturer's service support webpage first, but not too many maker post their service manual. There are a number 3rd part site that you can search. My favorite site is:

http://www.hifiengine.com/manual-library.shtml

The HiFi Engine site has comprehensive collection and is easy to nevigate. But you may not find what you need there. There are many other sites and you can Google your amplifier model to find the manual.

I have not been able to find a good tutorial on repair audio amplifier yet. This book by Bob Cordell offers some very valuable information on power amplifier:

https://www.overdrive.com/media/483565/designing-audio-power-amplifiers

If you find a good tutorial on the net or in book form, please, share with us.
 
Greetings; DIY forum has some sticky's on various topics. Getting informed on testing specific components and identifying them. searches online per individual component testing is easy enough. The cost investment part will be equipment.

If your soldering skills are nill you should find a junker to work on and a fair to good soldering station is highly recommended.

As noted for schematics and service manuals, you should become very familiar with what you are going to work on before you begin. You'll probably find many thread on ak per the equipment you have, too.
 
Nice!

Good advice Chaps, thanks very much.

I'll start with getting the schematic and getting my tools sorted out. I have a bit of experience of kit building and soldering and getting a junker to fiddle with is sound advice.

Yes, I'll be on the look out for tutorial books on troubleshooting. If I find any I'll report back.

Matt.
 
You probably do not want to take this equipment to a shop. The typical shop cannot afford to spend the time to do a good restoration. They will limit themselves to repair and get it working only. In some cases, there have been recommendations for those on AK that do this more as a hobby than as a living. That would be a much better choice if you send the work out.
 
You'll need a "working" knowledge of common components. Resistors, capacitors, diodes, transistors.

Locate a few good books on basic electronics. Read the first few chapters about the parts listed above until you think you understand what they do.

Knowing how things works is good. Knowing how they act when things break is a whole other topic that no one covers anywhere that I know of EXCEPT in AK threads.
There is a world of knowledge buried in here. Following threads and advise here is about the best and quickest way of learning I know of.

I've been digging up knowledge here and fixing stuff for years and still learning and asking and listening.

It takes a while.
 
FWIW -- I find solid state circuitry really difficult to understand. It tends to be frightfully complex, it operates to really tight tolerances and it tends to be quite intolerant of mistakes (e.g., a slip of a meter probe). I basically eschew troubleshooting ss stuff. Basic restoration (e.g., replacing known bad components) is straightforward, but great care must be taken when desoldering components from old/cheap printed circuit boards -- it's easy to overheat the board and mess up (lift) the printed traces. Don't ask me how I know this ;-)

I don't really intend to discourage the OP but I've just never gotten in sync with even ss amplifiers (and audio frequency amplifiers are about as simple as electronics get). I know of no good reference. The best thing to do, I'd opine, is to find a local, knowledgeable practitioner (e.g. a serious hobbyist) and apprentice oneself to him or her.

--------

gratuitous footnote:
Again FWIW, for a goof like me , vacuum tube circuitry is much easier to understand and thus to troubleshoot. Now, that said, there is the challenge of lethal voltage/current in most vacuum tube equipment (although some preamp and headphone amp circuits operate at relatively safe, low voltages).... but learning how to respect lethal HV is pretty straightforward -- and past that, the circuitry's usually very straightforward. Plus, there is a wealth of literature available to help one bootstrap one's repair/troubleshooting skill. www.tubebooks.org is a great place to start (e.g.).
 
mhardy6647 said:
FWIW -- I find solid state circuitry really difficult to understand. It tends to be frightfully complex, it operates to really tight tolerances and it tends to be quite intolerant of mistakes (e.g., a slip of a meter probe). I basically eschew troubleshooting ss stuff. Basic restoration (e.g., replacing known bad components) is straightforward, but great care must be taken when desoldering components from old/cheap printed circuit boards -- it's easy to overheat the board and mess up (lift) the printed traces. Don't ask me how I know this ;-)

I don't really intend to discourage the OP but I've just never gotten in sync with even ss amplifiers (and audio frequency amplifiers are about as simple as electronics get). I know of no good reference. The best thing to do, I'd opine, is to find a local, knowledgeable practitioner (e.g. a serious hobbyist) and apprentice oneself to him or her.

--------

gratuitous footnote:
Again FWIW, for a goof like me , vacuum tube circuitry is much easier to understand and thus to troubleshoot. Now, that said, there is the challenge of lethal voltage/current in most vacuum tube equipment (although some preamp and headphone amp circuits operate at relatively safe, low voltages).... but learning how to respect lethal HV is pretty straightforward -- and past that, the circuitry's usually very straightforward. Plus, there is a wealth of literature available to help one bootstrap one's repair/troubleshooting skill. www.tubebooks.org is a great place to start (e.g.).
Click to expand...

I will second this.
You really need to gather a few hundred dollars in tools to do things decently.
The gurus probably have thousands invested in tools.
 
I'm a newb as well and I've found these sites to be quite helpful in teaching me some theory as well as practical techniques. The westhost site previously mentioned is chock full of good stuff as well.

http://www.allaboutcircuits.com/

http://williamson-labs.com/

http://www.electronics-tutorials.ws/

This one is focused on car audio, but some very good info regarding electronics and amplification nonetheless:

http://www.bcae1.com/

I have no affiliation with any of these sites, only find them to contain useful information.
 
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