SEX C4S Question

[proud indian]

Like I said earlier, my dedicated music room is air conditioned and is set at 26°C. So that would be my room temperature. 

[proud indian]

There are more than a 1000 views and still I havent got a solution to this problem,  unless I am to assume that the temperature is the sole cause. Need some reassurance.

Shreekant

[Doc B.]

I have nudged the guys again to come up with a suggestion for this. I do wonder about the overall condition of the tinning on the pads on the PC board. It seems oxidized. Did you wipe the board with some sort of solvent, perhaps? The condition of the pads makes me wonder if there is a conductivity issue between the resistor leads and the pads they are soldered to. The resistor bodies don't look cooked as much as the solder joints do. You might just try reflowing those resistor connections.

[Alonzo]

I think temperature is only part of the cause for failure, seems that everything works after you have re-soldered in a part.  What kind of solder do you use?  Are you adding flux?  Something seems common to all your solder joints oxidizing and if the boards are all common the unknown is the solder material you use.  I'll share your board pics with some of the guys at work, they do a lot of inspect and review of this type stuff.

[proud indian]

I have soldered it more than 4 to 5 times as that is the number of led's that I have changed. Every time the led is changed, I check the joints and reheat them.
As of now, it is playing fine, and will continue to do so for a few months.. I have changed tubes.
To answer your question solder..... yes it has flux. I cant remember the type of solder, as I bought it off ebay. I thimk it was wbt.. it has a mix of silver if I recall right.
The amp is placed on isoblocks, on a maple wood slab, so it has more ventilation then with just the feet.


Shreekant