Whats up ya'll new guy here needs some help with his crate amp... pretty please

[rockaholic]

Hey guys so I got a crate xt120r amp from a buddy saying it does not work.  Here is the deal the first time I plugged my guitar into it just to see what would happen it worked. However it did not last long before it quit.  Now a couple clues for you guys I hope will help you to help me solve this mystery lol.  First off the power switch itself lights up when I turn it on indicating power. Now during that initial power on I did when it worked the led indicating which channel, clean/distortion I was using also lit up but as soon as the sound cut out so did the led light and has not re illuminated since and sound has not returned once since then either.  The fuse in the back is fine and I have it torn down to the board as we speak and can see no visibly bad solders or fried components. Any ideas would be awesome guys  :tu: I have a multimeter and know how to use it, but cant find a schematic showing me test points and values anywhere. It has a SLM electronics board if that helps. Thanks in advance for any and all help. I did search on here for awhile so if this issue has been discussed already I am sorry if I missed it.

[rockaholic]

Ok so this is the back of the power switch, the upper left has a white wire connected (which is slightly burnt on the insde of the slide connector I just found out) the upper right has a black wire and the lower left has a blue wire which comes directly from the fuse and the black wire directly from the power plug goes into the other end of the fuse. When the switch is turned in the off position there is no continuity between any of those pins. When I turn it on the upper right and lower right pins are connected but still nothing with the upper left. Could this be the problem?  I want to bypass the switch and connect that blue power wire to both of those other wires but I am afriad of electricuting myself or at least frying something else in the amp. Anyone know if those two upper pins should be connected?

[rockaholic]

Note to self never do that again  :duh, So in my infinite wisdom and finite patience I went ahead and swapped the black and white wires on the top pins and plugged it in to see if maybe there was a short in the switch.  As soon as I flipped it on I blew not only the fuse in the amp but the whole circuit breaker in my living room.  So... maybe ill wait for someone here to chime in b4 I really hurt myself lol.

[JPHeisz]

Hi,
It's most likely not a problem with the power switch. It may be a problem with either the switches or control circuit that selects the channel.
It would probably be a reasonable idea to locate qualified service and have them look at it. It may be something very simple.

[rockaholic]

Hi MJL, thanks for the reply man. As soon as I can find another fuse I am going to check out those two switches. It has one switch saying (clean)(solo/rhythm), then another switch for the (solo)(rhythm). Maybe a loose connection there. Only reason I dont want to take it in is I want this to be a learning experience for me on this free amp, that way if one of my actual amps I use have a problem maybe I will be able to better understand how to diagnose that  :tu:

[JPHeisz]

The switches themselves are easy, if they are the problem. I'm not sure what circuit they are using to switch between channels but it is probably very involved and not easily diagnosed.
Anyway, good luck