McIntosh Clinic
Bob Simon
clinic. Now it needs service - one of the channels intermittently
drops.
Do they still have those free clinics?
James...@gmail.com
Been a while since I heard of one but you can find people to service
them. The free clinic wouldn't have fixed it anyway.
Bob Simon
There's a guy in town who has a good reputation. A few months ago he
replaced some components in my NAD preamp/tuner and it cost around
$125. This was more than I expected but I haven't paid for electronic
service for 10 years so I really don't know what this work should cost
now.
Do you think there may be an advantage to sending it to McIntosh for
factory service? As I understand it, the transistors have to be
matched.
Dave
"Bob Simon" <nob...@nowhere.com> wrote in message
news:v5gm24h3iippgfebj...@4ax.com...
$125 for anything over and above a quick cleaning is cheap. Shops generally
are charging $50-$75 for a diagnosis/estimate these days.
If you've got the cash, sending it to the factory for servicing GENERALLY
guarantees a certain quality of service and availability of parts which your
around-town guy might (or might not) be lacking. We've all heard horror
stories though, so it's not a lock on perfect results. Sending it back to
the manufacturer almost always involves a lengthy period of time too. If
you have a knowledgeable, competent technician I don't think you're going to
do any better at the factory.
You can buy output and driver transistors in matched sets, a PNP mated with
an NPN with similar gain characteristics. You'd only ever need to replace a
transistor if it was bad, it's not a preventative maintenance item to
replace any.
If your channel cuts out randomly, it COULD be a transistor, but it's more
likely a cold solder joint or dirty switch in a piece of vintage gear.
Dave
Mark D. Zacharias
Unless the input level control is dirty, there really isn't much inside the
2100 that would cause a channel to be intermittent. No switches, no relays.
Your problem could well be elsewhere in the system.
Mark Z.
Chris Hornbeck
wrote:
>I have a McIntosh 2100 that was performance certified in 1976 at a
>clinic. Now it needs service - one of the channels intermittently
>drops.
Clean the switches and controls. Pay special attention to
the speaker on/off switch. If cleaning with Caig MCL doesn't
make it operate reliably, replacements are available from Mc.
It's also a very good idea to remove the driver cards
and to clean their contacts. Just a very, very, very
light coating of Caig on the board contacts and re-insert.
>Do they still have those free clinics?
Sadly, Davey O'Brien has been gone these several years. Nobody
else was willing to do the gig.
All good fortune,
Chris Hornbeck
"I have a gift for enraging people, but if I ever bore you,
it'll be with a knife." -Louise Brooks
Tim Schwartz
In response to Mark Z's reply. Sometimes the card edge connectors of
the driver boards can also cause noise. They can be cleaned, but
getting to them is not a task for someone who does not feel comfortable
doing serious repairs, as a lot of the amp has to come apart. (DON'T use
any abrasives on the contacts, just lacquer thinner on a swab will do,
clean ONLY the card edge, not the socket on the chassis. Work the card
in and out of the socket a few times to wipe the contacts.)
I've also seen the input differential transistors get noisy, and these
should be well matched if replaced. They are much more likely to cause
a noise problem than the output transistors. a few other parts on the
driver boards can also cause problems. Ask the repair shop if they can
gain match (beta match) transistors. If they seem to have no idea of
what you are talking about, take the amp elsewhere. If there is ANY
significant DC at the terminals (I'd say more than 10 mV) then the amp
needs service. Also, one channel running considerably hotter than the
other is reason for concern. The amp should be a bit warm after an hour
or 2 with no signal, but not hot.
Sending it to McIntosh is certainly a safe choice, but shipping could
be expensive depending where you are. You might want to look at the
McIntosh web site for an authorized servicer in your area.
Regards,
Tim Schwartz
Bristol Electronics
Bob Simon
wrote:
Thanks to all for the good advice.
Bob
BretLudwig
that Dave O'Brien retired several years ago and sadly passed away last
year or so.
I'd give all the switches a good cleaning, reseat all connectors and
cards and just for good measure go over any suspicious solder joint
carefully with RMA flux snd reflow it. Then clean carefully.
--
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Mark D. Zacharias
"BretLudwig" <bratz...@gmx.us> wrote in message
news:412e50be93843f71...@localhost.talkaboutaudio.com...
There is also a resistor on each driver board which needs to be resoldered.
It's fairly large and is pretty obvious when you see it.
Mark Z.
James...@gmail.com
wrote:
> "BretLudwig" <bratziru...@gmx.us> wrote in message
>
> news:412e50be93843f71...@localhost.talkaboutaudio.com...
>
> > McIntosh no longer runs free clinics for a variety of reasons, one being
> > that Dave O'Brien retired several years ago and sadly passed away last
> > year or so.
>
> > I'd give all the switches a good cleaning, reseat all connectors and
> > cards and just for good measure go over any suspicious solder joint
> > carefully with RMA flux snd reflow it. Then clean carefully.
>
> > --
> > Message posted usinghttp://www.talkaboutaudio.com/group/rec.audio.tech/
>
> There is also a resistor on each driver board which needs to be resoldered.
> It's fairly large and is pretty obvious when you see it.
>
> Mark Z.
It is probably not a good idea for most people to be reflowing solder
joints unless they have been identified as a problem and that person
has some experience soldering. The rest of your advice may well solve
his problems and are within the capabilities of just about everyone.