Why stuff dies...and I find schematics

[petemoore]

  2/3 of the time, taking only the last 6 months of 'stuff' into consideration, it's because the phenomenons are only partly understood by those using them.
  Bassman has it's tubes falling out, the retainer claws being well away from the tube bases, run anyway. Still works...fine design job Fender, if he was designing trucks you could probably run them with no oil !
  And I think 2/3rds is very modest when user induced failure is looked at in a broader sense. It would be interesting to do a poll and test all our willing musician/hi fi hooker upper friends to a few 'simple' questions, in the form of an ohmage test.
  1 Explain what "Do Not Exceed", and, "8 ohms minimum" means.
  2 Above requirement would allow 2x 8ohm speakers to be wired safely, in _____.
  3 What does "8 ohms Min" mean when it is above a stereo's speaker jacks.
  4 When two adjacent output jacks are on the back of a Mono amplifier, they are in a ______ configuration. [parallel or series].
  Fanon Pro Power 120, fancy and tight mixer/amp, looks like someone 'exceeded the minimum ohmage by 2x and ran it until the thick brick resistor lead tapered off above the board, blackened, looks like it was a 5 watter, a fine severe schorch job, both large PT's are toast...got all of it, the output board is mostly black, another board has signs of temperature problems also.
  Only the Realistic was treated within it's design expectations, sweetly powering advent speakers [mild volumes] bthen, just...fading...still 'works' but fades . The output section 'blips' the speaker when probed, what I guess is the input board transistors have voltages that are 'down' [all less than .6vdc].