wrote:
HI all,

I've no experience in repairing or in electronics but I opened my amp
to change an input jack and noticed this:

http://img360.imageshack.us/img360/8...mage0012tf.png

http://img451.imageshack.us/img451/6...mage0047pi.png

http://img84.imageshack.us/img84/744...mage0024my.png

It looks like zener diodes have burned the board under them.

The amp works great, the sound is ok, should I change them?

here is some schematics I found:
http://img84.imageshack.us/img84/4839/schemaparz6bm.png

here's the zeners' pdf:
http://www.ortodoxism.ro/datasheets/eic/1N5368A.pdf

thanks for your help

PS: sorry for my english...

Hello,

First, don't panic. I'd measure the voltage(s) and see if it(they)
is(are) correct. They are certainly running warm, as they have baked
the board a bit, and they are near some high wattage resistors. If the
voltage is correct, you could leave them alone.

If you want to replace them as a precaution, I'd solder the new one is
spaced up off the board a bit so that they get more cooling air around
them, maybe .25 in or so. Be very careful, as when they bake the board
like this the solder foils can get fragile.

Regards,
Tim Schwartz
Bristol Electronics