C4S board Problems

[Mordicai]

Paul, I tried three times to get that reading. Seems when I turn the sex upside down it want to play on both channels. And when I turn it right side it wants to play on the right channel only. I just barely got that 0 volt reading in on the OB before it strted playing both channel again. I played it for  about fifteen minutes and couldn't get it to drop a channel, and started getting concerned about the heat from the tubes. Do you think playing it upside down for a long time hurt anything from the heat. I will try again tomorrow.

[kgoss]

Hmmmmm.  If it works upside down but not right side up then gravity is completing a broken connection with the amp upside down. And since your amp has worked for over a year I would suspect a wire that was not soldered or more likely a wire that is broken under the insulation which usually happen when you nick a wire while stripping the insulation.  If I were you I'd do the chopstick test with the amp playing using cheap speakers or headphones. Concentrate on moving wires looking for one that makes the channel drop.

[Paul Birkeland]

Ken is spot on!

[Mordicai]

When this upside down magic started a few days ago, I of course felt the same way and started poking everything. My feeling was its a broken wire as Ive been over the amp many times without finding a bad connection. I was hoping to narrow down the search area a bit. What broken wires would cause the C4S resistors to burn like that? Back at it!! Thank god for the Stereomour. At least I can poke about to the Stones.

[Paul Birkeland]

When this upside down magic started a few days ago, I of course felt the same way and started poking everything. My feeling was its a broken wire as Ive been over the amp many times without finding a bad connection. I was hoping to narrow down the search area a bit. What broken wires would cause the C4S resistors to burn like that?

You're going to have to post a photo of what you're seeing.

[Mordicai]

http://www.pbase.com/mordicai/image/165195657

[Mordicai]

As you can see Paul both 150 are blackened. Only the 499 on the B side is blackened. The A side is shiny.

[Paul Birkeland]

Just for a point of reference, for how long do you generally leave your SEX amp on, and what's the approximate ambient temperature in the room? (Celsius is OK)

[proud indian]

Well, since we have the same problem, my room is air conditioned @ around 26°.

[Mordicai]

Paul, My amp goes on about 5 AM,and off about 9 PM. Temperature in the winter about 50-68 F. I live in the high desert so summer temps can be about 65- 90. If it gets hotter then that I turn on the air.  Could the poor connection to the MJE5731A, cause the heat?? That has now been fixed and seems like everything is ok

[Paul Birkeland]

summer temps can be about 65- 90.

If your room is 90F then there is a potential for problems.  Your cell phone and computer will also not last nearly as long as they should while operating at these temperatures.