PDA

View Full Version : Ampeg volume cutting out!


Terje79
01-03-2009, 11:19 PM
hello everyone,
I've had an ampeg vh-140c for a while just as a practice amp and lately the volume has been cutting out after a few minutes of playing. It is a solid state amp. If I crank the volume and play it it comes back for a while then will cut out again. Should I have it looked at or do you have any ideas of what I could check. I only paid maybe 150 bucks for it a while ago so would really rather not sink a lot of dollars into it. Any suggestions are greatly appreciated thanks!

SatelliteAmps
01-04-2009, 12:08 AM
Sounds like either a cold solder joint, or a broken part that is heating up and seperating. Cold solder joints are a bit of pain if you don't know what you are looking for.

Ronsonic
01-04-2009, 12:22 AM
First thing, try running a straight cable from the FX loop send to the return. Dirty FX loop normaling jacks are probably the most common problem.

Does it respond to percussive maintenance, does hitting, thumping, lightly dropping make a difference?

Adam's right, solders are always suspect and most especially on an SLM product.

Terje79
01-04-2009, 01:42 AM
I didn't really try any "percussive maintenance" yet. I will give it a shot tomorrow and see if anything happens, And will definitely try the fx-loop thing. Its really weird when i crank the volume up it'll be silent up until maybe half volume then it'll turn on and blow my ears out then I'll turn it back down and itll work for a few more minutes.

Ronsonic
01-04-2009, 08:46 AM
"Break-through" that's called, like you have to hit it with signal until it breaks through. Pretty direct symptom of either a failing connection or a faulty op-amp. Op-amp fails, loses bias to it's front end, jack enough signal into it, it rectifies, biases up from that and then works until it bleeds down again.

triodeamps
01-05-2009, 05:33 PM
Unfortunatley you will have to pull the entire board out. Look at the bottom of the board. You will more than likely see where some of the solder joints have this volcano looking aspect to them where the solder has rised up and vitually pushed away from the heat sink and other solder joint components loosing complete or intermitent contact. This includes the input and output jacks. If it dont have a nice shiny solder ball on the connection or component and looks thin and too flat resolder it.......