Can Audio Probe or Mini Bench Amplifier help to rectify a problem amplifier?

[FisTheGoon]

My amp got some problem.The guitar jack is not working.The funny thing is when inserted in cd/tape input,it will able to produce sound but not in the guitar input.I have changed the input jack but to no vain.I'm  wondering if Audio Probe or Mini Bench Amplifier can help to rectify the problem? ???Is there any danger I will face using them as the voltage is AC?
Thanks for your time.

[Paul Perry (Frostwave)]

I fone input works and the other doesn't, then I think either one socket is bad (not making contact or the track on the PCB near it broken, if the socket is soldered to the PCB) or (less likely) the selector switch is broken.

You should be able to sort this with just a continuity test with a multimeter (with the amp turned off!)

[petemoore]

  You know how to test for potentially lethal voltages at say B+?
  I would know where these are and how to drain related capacitors before proceeding.
  You should be able to trace where a cable plugged to input goes.
  Start with the cable tip, connect DMM [beepmode setting] to cable tip, look for a beep a input jack tip, follow the wire coming off the input jack tip lug to the circuit board, it should connect to something there, probably a resistor or a cap, if not, this is where a patch could re-connect it, if you can't follow the wires to determine what the connections should be, some other way of figureing it out [schematic etc.] will need to be tasked out.
  Do the ground/sleeve connections the same way.
  For 'fixes that aren't yet fixed' always consider 'it' could be 'and or something else'...input wiring and jack, in this case, is a choice place to begin.

[FisTheGoon]

Thanks for your guidance and i will try it out.I will post the result as soon i fixed it.