Preamp or Input jack?

[GospelBassMan]

Thank you so much, all you guys have left me with a wealth of information. I have so many options that will lead me to my solution. I love this bass, I think it's the best bass Yamaha ever made in my opinion.

 

[GospelBassMan]

Thanks I will look into it, the price is really nice.

 

[GospelBassMan]

The jack has switching terminals that turn the power on and off when you plug in a cord. It's possible the terminals are dirty, carbonized, bend, broken, or otherwise worn out. Inspect and clean the jack.

A dead battery can also cause static sometimes in active preamps. Install a fresh battery.

The nuts holding the controls on my TRB6P tend to work loose over time. This can allow the pots to move around a bit. Over time this can cause metal parts to fatique and break. I haven't taken my bass apart so I don't know if the pots are wired directly to the preamp or if they have flying leads. It could be as simple as a broken lead or bad solder joint.

If the preamp is relatively simple, a decent electronic technician will probably be able to repair it. It would be very helpful if Yamaha can provide the technician with a schematic. Unfortunately Yamaha does not have the best reputation for product support. I found it challenging to buy a replacement knob for my bass, when the bass was still in production. If the preamp cannot be repaired, there are after market preamps available that can handle the piezos.

Here is what the TRB6JP1 preamp looks like. I wouldn't be surprised if the TRB6P preamp has similar construction.
View attachment 3613121

As you see, the control pots are soldered directly to the circuit card. The problem could be as simple as a broken solder joint on the volume pot, or a bad volume pot.

I looked inside the cavity of the jack and it looks brown or rusty. Any ideas on how to clean it without damaging it? Also do you know of any place I can get replacement parts for my Yamaha TRB 6P?

 

[Wasnex]

I looked inside the cavity of the jack and it looks brown or rusty. Any ideas on how to clean it without damaging it? Also do you know of any place I can get replacement parts for my Yamaha TRB 6P?

I wouldn't mess around too much with the inside of the cavity as you are likely to do more damage to the electronics. The area is sealed so whatever is in there is likely to have been there since the bass was new.

If Yamaha says circuit card are unavailable, then about all you can do is look for used parts. You could call Yamaha service centers, but I doubt you will find any spare preamp modules.

I believe there is a service manual for the bass that includes a schematic a layout for the preamp. If the problem is not something simple like a broken wire or solder joint, bad jack, or worn out potentiomenter, then call Yamaha to see if there is an authorized repair center in your area. As long as the solid state components on the board are available, the preamp should be repairable. Any decent electronics technician should be able to fix it.

 

[GospelBassMan]

Hey My Fellow Bass Players,
You' re probably not going to believe this. I opened up the back of the my TRB 6P, exposing the preamp. I noticed that the end of the input jack was touching one of the solder points on the board. So, I got my pliers moved it reattached it to the board again and plugged it up. Needless to say, my Yamaha TRB 6P is back and working just great, sound so beautiful. Thanks for the great advice I received from all my fellow bass players.

 

[mcnach]

Hey My Fellow Bass Players,
You' re probably not going to believe this. I opened up the back of the my TRB 6P, exposing the preamp. I noticed that the end of the input jack was touching one of the solder points on the board. So, I got my pliers moved it reattached it to the board again and plugged it up. Needless to say, my Yamaha TRB 6P is back and working just great, sound so beautiful. Thanks for the great advice I received from all my fellow bass players.

Great result!
Now get some insulation tape and ensure it can never happen again, and enjoy the bass