[Vintage-Audio] preamp troubleshooting

Wed Aug 21 12:05:59 2002

Have you already done the obvious like cleaning the controls with a good quality
contact solution? The answer may be this simple.	

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From: Rick Larson <[email protected]>
To: [email protected]
Subject: [Vintage-Audio] preamp troubleshooting
Date: Wednesday, August 21, 2002 11:11 AM

My McIntosh C26 preamp started cracking, poping, hissing, ...
in the left channel.  Praying, turning it off and on again, and
crying didn't seem to help.  Finally, no sound in the one channel.

Earlier in the year, I replaced two power supply caps to remove
a hum from both channels.

I want to get this working again.  Tools I have include: DVM,
soldering iron, c26 service and owners manuals.  I can read a
schematic.

I can get access to a scope and function generator if needed.

The service manual has voltage test points that I can test.

Should I short the inputs first?
Would simple voltage checks be enough?
Other ideas?

I could scan in the schematic if someone would like to help
"if the voltage is not V at this point, part Y might be bad..."

If anyone hasn't seen the inside of a Mac, it is beautiful.
After working on old tube gear and other 'kits', I'm in awe in the
detail and neatness of the workmanship (craftmanship?).

Anyone in the Twin Cities want to stop by? :-)

BTW, I swapped in my trusty Hafler 101 to the joy of my 8 year old
"I love that one Dad" he said.

rick
-- 
mac, marantz, dynaco, bozak, magnapan, fisher, hafler, leach, swtp,
teac, jbl, plus some new stuff
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