hi guys.the amp when turned on doing on relays a sound like arc for one two seconds and after start normal. its like to try to start dificult.i replace all three relays the ptc the q560 trans few suspect diodes and the near ceramic cap..check everything and it looks fine.the strange is for a month is stopped to do this and start quiet and normal and before three days come back the same problem.i have resolder the most joints on the board.whats wrong? any idea somebody?
No answer from -speakerplans yet Full Speed ?
Not found a schematic but I am sure somebody here can find one .
It sounds like there is an ongoing fault in a component that is causing heavier loading on the relay contacts that causes arcing and blackening of the contacts due to heavier current being applied.
Obviously not bad enough to cause a complete failure but enough to cause your problem .
I suspect a leaky capacitor but without a circuit diagram its supposition.
Not found a schematic but I am sure somebody here can find one .
It sounds like there is an ongoing fault in a component that is causing heavier loading on the relay contacts that causes arcing and blackening of the contacts due to heavier current being applied.
Obviously not bad enough to cause a complete failure but enough to cause your problem .
I suspect a leaky capacitor but without a circuit diagram its supposition.
thank dunkan2.i have the service manual..the electrolytics is all replaced big and small.bc816 checked and shows ok..and the three resistors on it is all so ok.funny is a friend of me have q66 and doing the same problem..
As I don't have a circuit diagram you have me at a disadvantage but its possible your output devices are needing re-flowed ( resoldered ) in case of a high resistance joint and so you get a change in the overall current used due to heat .
Its also possible there is a bit of instability increasing the current but all this is conjecture as you said another model has the same fault then we are talking about a design issue then you would need to look at all the later changes made to later versions to see if it had been rectified.
Its also possible there is a bit of instability increasing the current but all this is conjecture as you said another model has the same fault then we are talking about a design issue then you would need to look at all the later changes made to later versions to see if it had been rectified.
yes possible.i measure direct after start about -20mv on bias on the problem chanel and the other measures +4-5mv till both in 3-4 minuts stabilize to about 7-7.5mv it happens when is cold and after this first minuts then run normal at 7.3 to 7.7mvolts for hours...other confusing thing for a month was away that problem and now start again.i check carefully again the outpout trans and resolder.this is the only part i left unsoldered unchecked because looks ok the joints.but thanks again for the tip.