I just picked up a used Spider 3 amp and it worked for about 15 seconds after I got it home.  Now, when I turn on the power switch all I get is a low amplitude thud. LED's don't light up, and the same thud, when it's turned off again. Since it's not under any kind of warrantee any longer and I'm pretty proficient at repairing electronics, I opened it up to look and see. What I found was surprising. The spades that connect the on/off switch were barely making contact. So I removed them and soldered the leads to the switch. I figured problem solved. Wrong, the amp still has no lights or sound, and the suggested reset of turning the amp on while depressing the clean channel button doesn't fix it no matter how long I hold it.

Is there another reset operation that can be performed? I did check the voltages on the test jack (H3) on the top of the board, but there seems that there are only two present. 3.28v on the +3_3v_P, and 3.26v on the RST_IN. RXD and TXD are at ground potential. Would the problem possibly be with the LM317, or the TDA 2050 voltage regulators? Again, I'm not sure what their outputs should be so I'm shooting in the dark.

On the bright side, the Transformer seems to be good (although I don't know what the proper output voltages are since I don't know what the windings are), and none of the capacitors are bulging, so I'm thinking they are all okay. And if the board is truly fried I at least have a speaker cabinet for my old laney head.

Mike