Orion 98 hissing

[jure_the_second]

I have been playing my Orion 5 for 15+ years now (it was made in 1998). On the latest gigs I got commented from soundmen, that the signal has a lot of noise. I've tested the bass at home on loud settings and noticed a great ammount of hiss compared to my other basses. The ratio between noise and string level is at a degree, that the bass is for me no longer usable until this is repaired.
 
The hiss is constant, non directional, it changes according to volume and preamp settings (opened filter gives more audiable hiss than closed, it gets louder with higher volume setting). Different amps and cables provide the same result. The ferrite bead is installed.
 
I've searched through the forum and found some suggestions, but none changed anything. I am not yet ready to send this machine to another side of the planet before exploring all other options. There are local electronics repairmen that could take a look at this, but before I call them I'd like to get your suggestions.
 
Questions:
 
1. Is there a life span on electronic components (pickups, pots...)? Could this hiss be simply a consequence of aging of an instrument?  
2. Does the shielding paint have a life span? Is it a part of maintenance to reapply it?
3. What test could I perform to localize the problem?
 
Best regards.
 
Jure

[mica]

Does the hiss change with the setting of the treble boost? Meaning, does the hiss increase as you boost the highs?
 
Do you have an orange capacitor on the output jack?

[jure_the_second]

I have changed the standard bass/treble module with filter/q module years ago and it worked fine until now.
 
Turning volume makes hissing louder, pan does not affect the noise, filter makes it lower when closed and higher when opened, q switch makes it louder when boosted.
 
The orange capacitor is installed. Here's the photo:
 

[mica]

Usually the cap on the jack is for the bass and treble module, if you remove it you will have more highs. 
 
But now that I know you've got a filter in there, I would suggest changing the IC. It's a TLE2022. If you can't find one locally, send me and email to arrange.

[jure_the_second]

Thank you for your suggestion.

I took the bass to the local repairman who changed the IC and yes, now the hiss is almost gone.

I usually had the volume control on bass completely open and had the gain knob on the amplifier set low. I was told that it is better to set the volume on the guitar lower and compensate with a higher setting on the amp in order to have less noise.

These days it is 16 years since I bought this Orion and it still induces smiles in me every time I grab it.

Best regards.

Jure

[mica]

I was pointed to this thread today, and found that my advice was not quite accurate. The correct IC for the Activator type filter module is a TLE2022. I've edited the original reference to correct that.