Shotgun

[Bob]

my 2 cents.

learn (at your own speed) to read a schematic. helps with checking signal, voltages, etc

learn to "map" or match schematic to board layout so you can continue troubleshooting

diagnosis - this is hard. all too often newbies come and give bad/missing information.
1) recapped and no sound, after about 50+ posts it was the tape monitor
2) did it work before you recapped? yes, no, maybe and several other diversions
and at over 40+ posts, back to square one.
3) newbie wanted phase 2 de-Oxit, problem was not something a spray would fix
but wouldn't accept a non-spray fix (like open up device, trace voltages, etc)

for the newbies, please do your research and find schematics and service manuals
and post them ( you learn more if you find it - rather than us feeding you for a day)
then post pictures ( no pictures taken at midnight or with flash or with old smartphones)
(do with hires setting, crop down (that's a right click on Windows), and put arrows
and text for that one cap - out of hundreds that most of us can't distinguish.)

and my personal request (refused by some) to document the fix/upgrade at the end.
to guide that next guy with similar problems, and to pay back the help from AK.

I personally love the descriptive process someone goes through to filter out
the meaningless diversionary "facts" that have nothing to do with the eventual
discovery of the problem. gets in the way and many dropout of helping when
faced with stubborn blockages (replaced the volume knob and now no sound
but forgot to say he pulled the PS caps out - bad example but representative)

there's an incredible amount of information out there, in all forms, in many styles:
1 maker fairs teaching preteens how to solder.
2. high schools teaching C++ programming classes.
3. kits with step by step assembling: solder one green 4inch wire from point 37 to point 43...

but til then, enjoy the music

 

[Bob]

sorry for the "Speech" above.

shotgun is not necessarily bad. I know there's the fix-the-problem-before-recapping
and the all too often newbie-introducing-yet-more-problems-with-bad-advice,

but from another viewpoint, if you're going to recap and replace worn/out-of-spec parts,
you can eliminate multiple problems (that can cause similar problems) and reduce
the troubleshooting to parts/circuits untouched by the recap/rebuild.

(I am always plagued by the weakest link theory - every time I fix something
I often have another problem pop up. and sometimes that hafler needs 3-4
things fixed)

but even before deciding one way or another, how about re-soldering all joints.
either (before you start - tape down the component side) remove all solder
and resolder, or with flux added, retouch all joints. this is especially true with
kits where the original solderer treated solder like gold (I see this often on
PAS units) and on a few NAD units.

the other side of all this, is no matter what you do the time spent is learning
to solve problems - at the very top of Maslov's hierarchy - self-actualization.

enjoy the music.

 

[OMGCat!]

I think the desire to shotgun comes with enthusiasm of someone starting out in the hobby. From a bit of cursory reading here and some YouTube videos it looks like a few changed parts here and there and she'll be ready to go in no time! Hmm, that didn't fix it, lets just change all of these caps and transistors and maybe some diodes too and that ought get it sorted. Then reality hits, the unit doesn't come out of protection, traces start lifting and great sadness is had by all.
The other day I had an amp that would go into and out of protection, the bias would jump all around and all sorts of wonky problems.
I can easily see why someone would start changing caps and transistors but in this case it was several bad solder joints (really the amp was ALL bad solder joints just some worse than others). Rather than changing anything some pokey diagnosis was done with a chopstick until I found a few transistors and resistors wiggling around in the board.
It DID need new caps but not bad enough to cause issues.

I'm not the most experienced out there but I do a lot of diag in my job as an automotive technician and know how easy it is to be lead astray.
Methodical troubleshooting with a good dose of experience is really the only way to be successful and the only ways to get experience is to either fake it until you make it or have a mentor looking over your shoulder while you work and pointing out where you should and shouldn't go.
I also mentor new people in said automotive field, usually guys straight out of UTI and then Porsche PTAP school, so I get to watch a scattered person get focused as they get more comfortable and start to build a troubleshooting flow chart in their heads as soon as a problem pops up.

These days the guys here are as close to most people will have as far as mentor-ship and there's only so far that can take a newbie. So yes I do cringe when I see people shotgun or destroy something that worked before they got in there but it's also great to watch them learn and hopefully rebuild it back to better than it was when they started. Some of them will take up the hobby, spend the time and money to learn and build their skill set and be the next masters at the job.

 

[maxhifi]

I know I'm pretty new here, but I really cringe when reading the posts about changing parts haphazardly and hoping it works. Not a purist: Some rational thought when troubleshooting would go a long way..
When you think it out, and actually troubleshoot the problem, it adds to the satisfaction of a job well done.
Visual inspection
Check voltages
Observe waveforms
Research

... Just sayin'
Let the flames begin

I think that shotgunning parts is very wasteful and expensive, and that people usually do this as a last resort, when they don't really know how to find the problem. I think we've all been there, at some point.

 

[xwarp]

I think we've all been there, at some point.

Yeah, I don't recall ever shotgunning anything.

 

[avionic]

If I shot gun some thing. Its with a 12 gauge. And it is dead.

 

[spinroch]

 

[elnaldo]

I've seen succesful and effective "shotgun" repairs, a tech bought like 20 or 40 small ICs to fix a board in an offset printing machine, a board that costs several thousand $$$ , in a couple of hours it was working. He said that tracing the fail with specialized equipment would be much more expensive and time consuming than replacing the ICs at once.

I did it sometimes with small boards, last time a protection circuit in a chinese amp without schematic. Replaced like 8 transistors and 6 caps all at once in a few minutes and the unit was fixed. I've tested before that there was no DC at the output and the relay was not engaged.

 

[leesonic]

So, are you saying it's worth spending 12 hours chasing your tail to make a repair, or 2 hours to "shotgun" the thing? It's horses for courses, not every repair job is the same. And people are so cheap, they don't want to pay any real money for you to repair their units. Look at the recent post about "how much money would you spend to get an amplifier repaired". That's why people like myself are getting out of the hobby, or scaling back.

Lee.

 

[spinroch]

I've seen succesful and effective "shotgun" repairs, a tech bought like 20 or 40 small ICs to fix a board in an offset printing machine, a board that costs several thousand $$$ , in a couple of hours it was working. He said that tracing the fail with specialized equipment would be much more expensive and time consuming than replacing the ICs at once.

I did it sometimes with small boards, last time a protection circuit in a chinese amp without schematic. Replaced like 8 transistors and 6 caps all at once in a few minutes and the unit was fixed. I've tested before that there was no DC at the output and the relay was not engaged.

The technique has it's place.
Of course, I was talking about Audio repair for the love of the craft.

 

[ghazzer]

I learned the hard way.

Other suggestions: Take good note and lots of pics. Need to know where you have been and where you are going.

If possible, make several printouts of the circuits you are working on and mark them up with voltage readings and other findings.

 

[Bob]

one of the basic problems is everyone wants a cheap, easy, <plus flipper margin...> fix
for everything. here in AK I see many folks with non-functional units that are looking
for a DeOxit solution. or to fix things.by simple think/ask and fix.

as we march into smaller and smaller SMD fabrication of audio boards we have only
the golden age stuff that is fixable, at least reasonably.

sometimes I can tell whether the OP is not knowledgeable about electrical circuits
or more often pushing a "diagnosis" and a "fix" that is not reasonable. then there's
the recapping with a reversed polarity. Or after about 40 posts there's new information
like prior butchering, newbies with cheap soldering irons, I forgot about that other fix.
all have examples now current and going nowhere.

I tend to answer as if I had the problem. then I puzzle it out over hours and sometimes
weeks (like the Hafler muting circuits using that @#%%^ J112 FET) then I get it.
so I always respond with "information" and sometimes I am wrong in detail, process
and diagnosis. But its also a test to see how far the problem owner wants to take it.

so, we come to a point where I now see folks telling the OP that he needs to take the
thing to a professional. there would be no way for the OP to learn enough technology
to be able to understand, diagnose, and fix his unit.

from another viewpoint I encourage the TOTL madness because the motivation is
now invest then profit - not about paying a lot of money up front for some/maybe
enjoyment. it would be a crime to not spend the money to save a unit TOTL or not.

I would prefer to keep AK's best professionals happy and continuing to refresh/rebuild
this equipment.

 

[MannyE]

I don't get why the profit motive is entered into it. This is an amateur enthusiast board. Right? Discussing the down-sides of shotgunning in the context of destroying a wonderful piece of equipment should be the focus. Discussions about if it pays to do so or not for professional reasons seems to be irrelevant in this context.

As an enthusiast I will often do things that are not cost-effective from a business point of view because I am doing this as a hobby.

I really don't care if I spend $30 more to replace every single capacitor on a board because I want to be sure I restored whatever I am restoring as best as I can and assure it has the longest life possible. Telling me that it's "wasting money" is of no consequence to me, especially from the point of view of a tech who does repairs for a living.

Now, if that same tech tell me that it's dangerous to "shotgun" because excessive de-soldering and re-soldering can start to ruin traces etc. that is valuable information that should be heeded because these guys know what they re talking about. Similarly, if I send something away to be restored, I will usually listen to the tech who again, knows WAY more than I do about these things.

@leesonic I would hate to think you would get out of servicing hobbyists because of some skinflints who don't value your time and skills. Suffice to say that the hobby of vintage audio isn't about "cheap" (to paraphrase a popular thread) and I think anyone not willing to pay the price of admission needs to find a new hobby or learn to do the repairs themselves. I've done some very basic repairs and I respect and admire anyone that can find their way around a receiver/amp.

 

[Bob]

mixing metaphors. people don't want to spend $400+ to fix something. I tell them it will
be worth $2-5K more if you keep it and fix it. that's the money motivation. like buying
amazon when it was $23. therefore - QED: spend 400 to make $2K - easy for anyone
to understand. alternative is to dump and landfill. enjoy for decades, sell for profit.

most folks who come here with a problem unit, generally do not fix them
either because no money, no knowledge, or no motivation. lets motivate them
either learn (hard and time consuming) or appeal to their inner flipper.

therefore to keep the giants of AK happy like @leesonic (who has posted here about this
exact money thing) I think of the hundreds of units these giants have returned to service
and the thousands of the future. professional yes. money? that's the issue.

and as for starting to learn to diagnose and fix. how many? one or two for dozens of newbies
OPs with broken units. and how is that knowledge returned to AK? I've asked several
folks who I think I have helped to summarize their findings (over 50+ posts) and they refused.

and yes it's supposed to be an enthusiast's board but how many times have you seen
did I overspend for xxx? how much is that A25/L100/D9 worth? I have ABC - what's it worth?
and there's always someone looking to make money under the guise of fixing something.

and my final gripe is that there are certain things in life that are not money related - like music
but the rest of the world is cutting cable, buying cheap stuff from China. flipping TOTL Pioneer
and marantzs, switching cell services to save a few bucks a year. flying airlines that charge for
everything because it's cheaper (money), etc

I miss the detailed explanations from @leesonic and others for their concise descriptions,
their analysis of the issues, their re-engineering, and general professionalism. compare
this to the flippers who want the BOMs and substitutes. what's the end result - they flip it.
they never come back and describe their journey into restoring saveable gear with detailed
guides and descriptions. and then there's the units that show up on AK - total hack jobs.

so, I would never buy something undocumented, from an obvious flipper whose motivation
is not restoring audio units BUT for profit. Everything I buy is assumed to be bought at
flea markets, estate sales, and dumped for a profit. and if I were to buy from an AK giant
I would not challenge it - I would assume it was professionally "certified".

any how. to those who come here to learn - great, and do it. and KUDOs to the giants
that give of their advice freely through their detailed descriptions. one would hope the
padawans become the Jedi knights.

no matter how you feel about the money motivations and pervasive auras - enjoy the music

 

[MannyE]

mixing metaphors. people don't want to spend $400+ to fix something. I tell them it will
be worth $2-5K more if you keep it and fix it. that's the money motivation. like buying
amazon when it was $23. therefore - QED: spend 400 to make $2K - easy for anyone
to understand. alternative is to dump and landfill. enjoy for decades, sell for profit.

most folks who come here with a problem unit, generally do not fix them
either because no money, no knowledge, or no motivation. lets motivate them
either learn (hard and time consuming) or appeal to their inner flipper.

therefore to keep the giants of AK happy like @leesonic (who has posted here about this
exact money thing) I think of the hundreds of units these giants have returned to service
and the thousands of the future. professional yes. money? that's the issue.

and as for starting to learn to diagnose and fix. how many? one or two for dozens of newbies
OPs with broken units. and how is that knowledge returned to AK? I've asked several
folks who I think I have helped to summarize their findings (over 50+ posts) and they refused.

and yes it's supposed to be an enthusiast's board but how many times have you seen
did I overspend for xxx? how much is that A25/L100/D9 worth? I have ABC - what's it worth?
and there's always someone looking to make money under the guise of fixing something.

and my final gripe is that there are certain things in life that are not money related - like music
but the rest of the world is cutting cable, buying cheap stuff from China. flipping TOTL Pioneer
and marantzs, switching cell services to save a few bucks a year. flying airlines that charge for
everything because it's cheaper (money), etc

I miss the detailed explanations from @leesonic and others for their concise descriptions,
their analysis of the issues, their re-engineering, and general professionalism. compare
this to the flippers who want the BOMs and substitutes. what's the end result - they flip it.
they never come back and describe their journey into restoring saveable gear with detailed
guides and descriptions. and then there's the units that show up on AK - total hack jobs.

so, I would never buy something undocumented, from an obvious flipper whose motivation
is not restoring audio units BUT for profit. Everything I buy is assumed to be bought at
flea markets, estate sales, and dumped for a profit. and if I were to buy from an AK giant
I would not challenge it - I would assume it was professionally "certified".

any how. to those who come here to learn - great, and do it. and KUDOs to the giants
that give of their advice freely through their detailed descriptions. one would hope the
padawans become the Jedi knights.

no matter how you feel about the money motivations and pervasive auras - enjoy the music

I'll you one thing, the more I see those detailed threads, the more I am convinced that beyond the basics, and I mean the very simple stuff like cleaning pots, etc., equipment should be sent out to a tech. But I do really enjoy watching them!

 

[spinroch]

I'll you one thing, the more I see those detailed threads, the more I am convinced that beyond the basics, and I mean the very simple stuff like cleaning pots, etc., equipment should be sent out to a tech. But I do really enjoy watching them!

MannyE: Are you one of the The Knights Who Say "Ni!" ???

 

[MannyE]

MannyE: Are you one of the The Knights Who Say "Ni!" ???

We are no longer the knights who say Ni! We are now the knights who say ekki-ekki-ekki-pitang-zoom-boing!

 

[spinroch]

Nice! I will have to update my files.

 

[BillWojo]

Bob mentioned the members that never come back after a long session of troubleshooting help. That is a pet peeve of mine.
I have worked on machine tools that I'm not familiar with and have contacted the factory service department for some guidance. Sometimes it takes several calls. After fixing the machine I always make one last call to let them know what I found to be the problem. It helps them and I like to thank them. I often filled in on the service tech line when I worked at Bridgeport Machine Tools. Nothing like being appreciated for all the tech advise. Most customers never called back.

BillWojo

 

[Overundr1]

Not discounting those pieces that require so much time spent in dis-assembly to get to the problematic board that not replacing all known culprits before re-assembly (and testing) seems a bit silly.
-Lee