On Thu, 15 May 2008 10:44:17 GMT, Tim Schwartz <timhhk@[EMAIL PROTECTED]
>
wrote:
>Bob Simon 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.
>>
>> Do they still have those free clinics?
>
>
>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 ****pping 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
Thanks to all for the good advice.
Bob
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