My Onkyo P304 treble potentiometer is becoming unresponsive and I am considering my options.
Undertake a diy replacement, (if a suitable alternative component is available)
Remove, strip and attempt a diy repair of the potentiometer if at all possible.
source an original -which could take forever … and a day, and is my least preferred path.
Replace the P304 preamplifier.
I am not seeking a debate on which is a better pre-amp, or the availability of modern, better, etc.
My system consists of an Onkyo P304 pre-amp and Onkyo M-504 power amp. Denon POA-2800, Luxman PD284, Linn LP12, Revox A77, SSll valve preamp with a pair of ACA Monoblock amps through Energy Veritas 2.1 bookshelf speakers.
Needless to say, I am very happy and comfortable with what I have, and would prefer to retain what I have, rather than go down the rabbit hole for bigger and better.
Having said that, is there anyone who has had similar issues and managed to repair, or replace using a suitable alternative?
Undertake a diy replacement, (if a suitable alternative component is available)
Remove, strip and attempt a diy repair of the potentiometer if at all possible.
source an original -which could take forever … and a day, and is my least preferred path.
Replace the P304 preamplifier.
I am not seeking a debate on which is a better pre-amp, or the availability of modern, better, etc.
My system consists of an Onkyo P304 pre-amp and Onkyo M-504 power amp. Denon POA-2800, Luxman PD284, Linn LP12, Revox A77, SSll valve preamp with a pair of ACA Monoblock amps through Energy Veritas 2.1 bookshelf speakers.
Needless to say, I am very happy and comfortable with what I have, and would prefer to retain what I have, rather than go down the rabbit hole for bigger and better.
Having said that, is there anyone who has had similar issues and managed to repair, or replace using a suitable alternative?
Last edited:
Last edited:
Thank you for the quick response.
Thank you Hugo for the link.
I have attempted removing the front panel but after removing the knobs,something is preventing the front panel from being removed. I am not able to identify the obstacle so might need to have another go at it.
Thank you Hugo for the link.
I have attempted removing the front panel but after removing the knobs,something is preventing the front panel from being removed. I am not able to identify the obstacle so might need to have another go at it.
Take you time.
Tiny plastic 'grips' that act as a kind of hook sometimes make fronts difficult to remove.
Hugo
Just a quick update...
I sprayed both pots with contact cleaner and rotated them back and forth repeatedly, then followed up with more of the same. After a short drying period I powered the system up and did notice and improvement in both potentiometers performance, with audible differences in treble and bass.
I also decided to give other switches some attention including the MC/MM (moving magnet/moving coil) switches.
Thanks for the feedback and to Hugo for the link to the potentiometer supplier.
I sprayed both pots with contact cleaner and rotated them back and forth repeatedly, then followed up with more of the same. After a short drying period I powered the system up and did notice and improvement in both potentiometers performance, with audible differences in treble and bass.
I also decided to give other switches some attention including the MC/MM (moving magnet/moving coil) switches.
Thanks for the feedback and to Hugo for the link to the potentiometer supplier.
From personal experience I find it quite difficult to buy. Cleaning usually removes crackle, hardly the dirt on the resistance tracks was so thick that a standing wiper did not protrude.
But as you say - if it was so then it has to have been so 😉
I agree with your comment re: personal experience.
However, although an improvement was noted after the cleaning exercise, I would not necessarily attribute the outcome to cleaning. You would have noted that: "I also decided to give other switches some attention including the MC/MM (moving magnet/moving coil) switches." The movement and spraying contacts in the MC/MM coils could have contributed! I am thinking the switch could have been stuck between selectors. But for the moment, I am leaving well enough alone.
However, although an improvement was noted after the cleaning exercise, I would not necessarily attribute the outcome to cleaning. You would have noted that: "I also decided to give other switches some attention including the MC/MM (moving magnet/moving coil) switches." The movement and spraying contacts in the MC/MM coils could have contributed! I am thinking the switch could have been stuck between selectors. But for the moment, I am leaving well enough alone.
Yes, if you were listening to a vinyl player. Otherwise they are not in the signal path.
That would be most improbable. Movement of the switch would have been physically blocked.
If you are listening to vinyl then I would test removing C211 and R215 - you may hear some difference:
I have seen intermittent pots and switches for several reasons:
1) dirty contacts, as you have already addressed
2) cracked solder connections to the main pcb - easy to fix but access may require removal of the entire main board. Some units have a removable bottom plate.
3) loose terminals within the pot, where the terminals are riveted to the little board with the resistive tracks (as shown in the photo). This can be checked by measuring the resistance between terminals with a multimeter. Open circuit means no connection.
For # 3 you can replace the pot, or remove the pot and try to "re-crimp" the rivet connection with pliers, but be careful as too much force may break the brown phenolic board. The re-crimp has worked for me.
Good luck
1) dirty contacts, as you have already addressed
2) cracked solder connections to the main pcb - easy to fix but access may require removal of the entire main board. Some units have a removable bottom plate.
3) loose terminals within the pot, where the terminals are riveted to the little board with the resistive tracks (as shown in the photo). This can be checked by measuring the resistance between terminals with a multimeter. Open circuit means no connection.
For # 3 you can replace the pot, or remove the pot and try to "re-crimp" the rivet connection with pliers, but be careful as too much force may break the brown phenolic board. The re-crimp has worked for me.
Good luck
