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DIY in training..where do I start?

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Anonymous
May 30, 2005 2:54:05 PM

Archived from groups: rec.audio.tech (More info?)

I would like to get into audio repair/DIY as a hobby.
Where do I start? I have good logic when it comes to small fixes; I
intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
kit (mindless).
I have many pieces of equipment that most likely are an easy fix if I
had more knowlege. Any recommendations?

Thanks,
dmc

More about : diy training start

Anonymous
May 30, 2005 3:12:17 PM

Archived from groups: rec.audio.tech (More info?)

xtrapikles@ wrote ...
>I would like to get into audio repair/DIY as a hobby.
> Where do I start? I have good logic when it comes to small fixes; I
> intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
> kit (mindless).
> I have many pieces of equipment that most likely are an easy fix if I
> had more knowlege. Any recommendations?

Share you list of possible projects and get some suggestions
about which are good starting points, etc.
Anonymous
May 31, 2005 1:02:48 AM

Archived from groups: rec.audio.tech (More info?)

In <1117475645.206393.186340@f14g2000cwb.googlegroups.com>, on 05/30/05

at 10:54 AM, xtrapikles@yahoo.com said:

>I would like to get into audio repair/DIY as a hobby.
>Where do I start? I have good logic when it comes to small fixes; I
>intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
>kit (mindless).
>I have many pieces of equipment that most likely are an easy fix if I
>had more knowlege. Any recommendations?

At the consumer level it is becoming harder and harder to gain the
knowledge that you need. For most non consumer items, board swapping is
the first level of repair. With a few exceptions, audio manufacturers
will not supply PC boards, service must be done at the component level.
Board level and component level repair are very different mindsets.
I've had computer repair people come to me touting their success at
repairing computers. It's one thing to deduce that if nothing is
displayed on the monitor that you've got a bad monitor or video card,
it's quite another to figure out which little part on the video card
needs to be replaced. The computer repair types I've seen cannot
operate the most basic test equipment.

Very little was ever written specifically about repairing audio
equipment. One must learn "first principles" (fundamental electronics
and physics) and generalize them for audio on your own.

Publications I've found useful: "The Radio Amateur's Handbook" (really,
just about anything the ARRL publishes will be useful). Some colleges
offer a course "The Physics of HiFi" to non-science majors. That
textbook is generally useful at a basic level, but you may disagree
with some of their theory or conclusions. (When you do, that's a sign
that you are ready for graduation and moving out on your own)

Some older magazines are useful: "Radio Electronics", "Radio & TV
News", "Popular Electronics" and "AUDIO Magazine". At this point they
are mostly found in someone's attic and the information they contain
can be very dated, but the fundamental principles have not changed in a
few billion years. The discussions about basics found in these
magazines were very good. Over the years there were changes in
ownership, editorial content, and mergers with and between these
magazines. While it is mostly Ham Radio oriented, "QST" will sometimes
run an interesting article.

Another great publication is the "Journal of the Audio Engineering
Society". While this may have a bit too much math for some, you will
get to stay at the leading edge. It may be some years before
information aired in the JAES becomes incorporated in a product. From
time to time the same authors will wrote for "AUDIO Magazine" (JAES is
for engineers, AUDIO was for consumers)

There are some technical schools that claim to offer consumer
electronics training. Perhaps the good graduates are not comming my
way, but I've never been impressed with their diagnostic or theoretical
skills. In one case a fellow brought in a unit with very specific
instructions "Replace IC101". He claimed that his friend was a consumer
electronics instructor at a local technical school and had diagnosed
the problem. I sounded *VERY* bad, but I had the unit working in less
than 10 minutes (including disassembly time for a model I had never
seen before) -- no parts were replaced. I then ran the unit for several
hours without any hint of a problem with IC101.

http://www.roger-russell.com is a good online site if you are
interested in audio product history. Roger was a designer at McIntosh
Laboratories for many years.

-----------------------------------------------------------
spam: uce@ftc.gov
wordgame:123(abc):<14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13> (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------
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Anonymous
May 31, 2005 1:02:49 AM

Archived from groups: rec.audio.tech (More info?)

"Barry Mann" wrote ...
> It's one thing to deduce that if nothing is
> displayed on the monitor that you've got a bad monitor or video card,
> it's quite another to figure out which little part on the video card
> needs to be replaced. The computer repair types I've seen cannot
> operate the most basic test equipment.

To be fair, its hardly worth it anymore. Service information (schematic
diagrams, parts lists, etc.) are difficult-to-impossible to obtain for
many
things. And microscopic surface-mount devices are getting harder and
harder to probe, to replace, or even to read without a microscope.
Anonymous
May 31, 2005 5:37:26 AM

Archived from groups: rec.audio.tech (More info?)

In <119nml512r6tk9b@corp.supernews.com>, on 05/30/05
at 08:31 PM, "Richard Crowley" <rcrowley7@xprt.net> said:

>"Barry Mann" wrote ...
>> It's one thing to deduce that if nothing is
>> displayed on the monitor that you've got a bad monitor or video card,
>> it's quite another to figure out which little part on the video card
>> needs to be replaced. The computer repair types I've seen cannot
>> operate the most basic test equipment.

>To be fair, its hardly worth it anymore. Service information
>(schematic diagrams, parts lists, etc.) are difficult-to-impossible to
>obtain for many
>things. And microscopic surface-mount devices are getting harder and
>harder to probe, to replace, or even to read without a microscope.

I know, but HiFi manufacturers don't stock many boards. Most will
authorize replacing a board (in or out of warranty) only if the
original is burned beyond recognition. Even if they will ship a new
board, the cost is very high relative to the original product cost.

In addition, it is not so easy to pull the board for replacement or
repair. As a final insult, some of the boards I'm seeing are too large
for many of the surface mount replacement jigs. Sometimes, if the part
is accessible, hand tools can be used to replace a part without needing
to pull the board. But, it takes a bit of skill and practice to remove
and replace a 100+ pin device without pulling up or shorting a trace.

Service information is often incomplete. Yes, there is a schematic, but
with hundreds of pins, each with a cute little 3 or 4 character tag to
describe its function (forget about definitions for the "tags"), it's
hard to be sure if you have a problem with a large chip, the board
traces, or one of the "glue" parts. Essentially one is dealing with a
sparsely documented, nonstandard, multi-tasking multiprocessor computer
network. Sometimes manufacturers will document the test routines,
sometimes not. -- And the unit must be mostly working before the test
routines will run.

---

In the future things will get much worse because the copyright holders
are insisting that all data be encrypted before it leaves the chip.
This means that, without very specialized tools, one will not be able
to do much in the way of signal flow analysis other than verifying that
pulses are within reasonable voltage and timing limits. And, if one
could have such a tool, then the whole encryption system is open to
being easily hacked -- and you would need a different tool, or at least
a different decryption key for each chip.

If one invests enough time in the project, it is possible to become
familiar with a chipset family, but in a few months the product will
become obsolete, a new chipset will replace it, and obsolete your
knowledge. At the (team) design level this can be great, never boring
fun. One can spend some time to become familiar enough with a new chip
to design, debug, and prepare your product for production, (automated
tools and the chip's manufacturer can help) then you move on to the
next project. At the service level, we are stuck with the product for a
decade or two and, other than a few early failures, the service
community won't start seeing significant numbers of the product for
several years. By this time the original design team is dispersed and
won't be much help.

Service makes sense if one will see tons of a specific product and can
justify the investment to train and equip yourself for that product.
This suggests that a small team should suit-up for a particular chipset
and all products using that chipset should be routed to that team.

-----------------------------------------------------------
spam: uce@ftc.gov
wordgame:123(abc):<14 9 20 5 2 9 18 4 at 22 15 9 3 5 14 5 20 dot 3 15
13> (Barry Mann)
[sorry about the puzzle, spammers are ruining my mailbox]
-----------------------------------------------------------
Anonymous
June 2, 2005 12:27:55 AM

Archived from groups: rec.audio.tech (More info?)

<xtrapikles@yahoo.com> wrote in message
news:1117475645.206393.186340@f14g2000cwb.googlegroups.com...
> I would like to get into audio repair/DIY as a hobby.
> Where do I start? I have good logic when it comes to small fixes; I
> intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
> kit (mindless).
> I have many pieces of equipment that most likely are an easy fix if I
> had more knowlege. Any recommendations?
>
> Thanks,
> dmc


Hi dmc,

a good place to start is to get some boxed kits - I think the name was
Vellman or something like that - maybe Radio Shack have them. They can be
quite basic and then move on to the more difficult ones. They also have
good instructions about how the circuits work which is a good way to learn.

Good luck
Mike
Anonymous
June 4, 2005 5:07:23 AM

Archived from groups: rec.audio.tech (More info?)

xtrapik...@yahoo.com said:

I would like to get into audio repair/DIY as a hobby.
Where do I start? I have good logic when it comes to small fixes; I
intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
kit (mindless).
I have many pieces of equipment that most likely are an easy fix if I
had more knowlege. Any recommendations?


Try Googleing DIY audio.

Another place that might be helpful.

www.diyaudio.com There are several groups there covering the whole
range of audio projects and some pretty smart guys.
Anonymous
June 6, 2005 7:07:05 PM

Archived from groups: rec.audio.tech (More info?)

"NYOB123@peoplepc.com" <NYOB123@peoplepc.com> writes:

> xtrapik...@yahoo.com said:
>
> I would like to get into audio repair/DIY as a hobby.
> Where do I start? I have good logic when it comes to small fixes; I
> intalled a new PCB in my Beogram 2000 (simple); I intalled my own DSL
> kit (mindless).
> I have many pieces of equipment that most likely are an easy fix if I
> had more knowlege. Any recommendations?
>
>
> Try Googleing DIY audio.
>
> Another place that might be helpful.
>
> www.diyaudio.com There are several groups there covering the whole
> range of audio projects and some pretty smart guys.


Check also the links at
http://www.epanorama.net/links/repair.html



--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
!