unclej Posted May 13, 2005 Report Share Posted May 13, 2005 i took a peavy TNT130 bass amp in on trade and sold it to one of my students..he brought it back in yesterday (after 3-4 months) and it's honkin'. not screeching or screaming or wailing...honkin'. as soon as you turn the power switch on there is a steady, loud lower-mid range squawk/ honk. it's not controllable with any of the controls..in fact it has two pc boards inside right next to each other. one apears to control all of the switches and knobs and inputs and the other the output. there's a jumper between the two boards and i disconnected that and still get the honk. i tried another speaker with the same results. all of the caps test ok and in fact, the only component that i know how to test that doesn't test ok is a tiny little diode. could that one bad diode cause all that racket? any other suggestions about what else might? thanks Quote Link to comment Share on other sites More sharing options...
TenderSurrender Posted May 14, 2005 Report Share Posted May 14, 2005 i took a peavy TNT130 bass amp in on trade and sold it to one of my students..he brought it back in yesterday (after 3-4 months) and it's honkin'. not screeching or screaming or wailing...honkin'. as soon as you turn the power switch on there is a steady, loud lower-mid range squawk/ honk. it's not controllable with any of the controls..in fact it has two pc boards inside right next to each other. one apears to control all of the switches and knobs and inputs and the other the output. there's a jumper between the two boards and i disconnected that and still get the honk. i tried another speaker with the same results. all of the caps test ok and in fact, the only component that i know how to test that doesn't test ok is a tiny little diode. could that one bad diode cause all that racket? any other suggestions about what else might? thanks ← Ahh this is where i get to make a post.. and then get slaughtered by everyone else because i cant say i have much idea wha so ever.. but im doing an electronics course at the moment so ill give it a go If i remember correctly Diodes stop the flow of electricity flowing the wrong way around a circuit especially when using motors etc... Any failing/failed component on a board cant be good and i suppose yes it is possible for that to make all the noise But this is just an educated guess ~~ Slain Angel ~~ Quote Link to comment Share on other sites More sharing options...
unclej Posted May 14, 2005 Author Report Share Posted May 14, 2005 hey..thanks for the educated guess..and i doubt that anyone here is gonna flame you for trying to help..well, there is that one guy but he's not very big. Quote Link to comment Share on other sites More sharing options...
essexdave Posted May 14, 2005 Report Share Posted May 14, 2005 Not terribly helpful but my brother has had 2 TNTs and both developed exactly what you described, so far no one has been able to fix either of them and he got rid of them for a Trace Eliiott stack. I'd love to know what the cause is if you ever track it down. Quote Link to comment Share on other sites More sharing options...
TenderSurrender Posted May 14, 2005 Report Share Posted May 14, 2005 hey..thanks for the educated guess..and i doubt that anyone here is gonna flame you for trying to help..well, there is that one guy but he's not very big. ← lol well im here to help whenever i can I agree with essex dave that itll be intresting to see the outcome of this... if your feeling rebelious and handy with a soldering iron try replacing the diode i mean heh cant get any worse rite? Good luck ~~ Slain Angel ~~ Quote Link to comment Share on other sites More sharing options...
unclej Posted May 14, 2005 Author Report Share Posted May 14, 2005 so far i've found one diode and one small cap that test bad...i'll let you know if that fixes it. Quote Link to comment Share on other sites More sharing options...
thedoctor Posted May 14, 2005 Report Share Posted May 14, 2005 As long as noone is getting any flack over their input, I shall add mine. You have one or two leaking output transistors. They can, in fact, still test good with a common transistor tester. I have a gain/current tester that catches these little turds when they get cranky but it is usually more efficient to just replace both (for like $14.00) and move on. Duck season! Wabbit season! Wabbit season! Duck season! FIRE! (Quote from Loony Toons) Quote Link to comment Share on other sites More sharing options...
lovekraft Posted May 14, 2005 Report Share Posted May 14, 2005 I tend to agree with thedoctor - it's obviously a power section problem, and those would be the most likely suspects. Of course, I'm no solid state power expert, so take anything I say on that subject with a whole block of salt. Quote Link to comment Share on other sites More sharing options...
unclej Posted May 15, 2005 Author Report Share Posted May 15, 2005 well, we all know i'm no solid state guru but this is a simple board so i'll replace the little rascals and let you know what happens. Quote Link to comment Share on other sites More sharing options...
TenderSurrender Posted May 15, 2005 Report Share Posted May 15, 2005 As long as noone is getting any flack over their input, I shall add mine. You have one or two leaking output transistors. They can, in fact, still test good with a common transistor tester. I have a gain/current tester that catches these little turds when they get cranky but it is usually more efficient to just replace both (for like $14.00) and move on. Duck season! Wabbit season! Wabbit season! Duck season! FIRE! (Quote from Loony Toons) ← Perhaps i should of thought of that Good call doctor A failing diode surley wont be helping matters though? Not quite sure but ahh there we go ~~ Slain Angel ~~ Quote Link to comment Share on other sites More sharing options...
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