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Thanks, guys!

6/6/2000 11:02 PM
Ed K
Thanks, guys!
Thanks to all of you who sent speedy replies to my request for the MP-1 schem. It's a little hard to read, but hey, two days ago I had nothing!! Unfortunately, I don't think it's gonna help me after all. The problem, briefly, is this: When I turn it on, it seems to work OK for a short time. After I play through it for about 20 minutes, I start to notice a real lack of sustain and the distortion gets real weak. Also, there's a hum going on there, and it's defenitely not 60-cycle hum. I replace the tubes regularly, and this particular time, I even took the tubes back and exchanged them for another set. Same thing. I really love this preamp and I've had it for 11 years. This has really got me puzzled. There are no visible signs of overheating anywhere. I apologize for the length here, but has anyone else experienced this? Could it be my transformer? Or maybe caps? I just wish I knew where the test points were, and what readings I should be getting. Thanks in advance for any assistance, and again, forgive me for the length.  
Ed K
And now, a word from our sponsors:

6/7/2000 2:32 PM

11 years old It could be the solder (not a joke) When I work on older boards(not music) interemittent problems with heat like that can be caused by bad solder joints that show up after time. They were bad from the start but the connection was good enought for awile.
6/7/2000 7:14 PM
Reid Kneeland

"11 years old It could be the solder"
Hmmm... maybe that's why my 11-year-old daughter is acting so weird. I figured it was hormones, but maybe I should open her up and reflow all her joints. (Believe me, I've been tempted...)  
P.S. I, of course, was a perfect angel at 11.

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