Post Number: 29
|Posted on Friday, March 02, 2007 - 3:13 am: |
Hello, this is in regards to a project Aria Pro II bass, model SB-LTD, I found with stock Alembic AXY pickups (I moved this thread to troubleshooting from the Alembic Basses forum now that I actually *have* the bass and know about its troubles that need to be shot!).
As the subject title says, when I plug the bass in, there is just a weak distorted signal coming from the pickups. I changed the battery so that doesn't appear to be the culprit.
I read a little bit in the archives about people tweaking with the trim pot in the case of distortion, but I did that and nothing seemed to happen. I don't know much about the electronics so I won't be able to do much more than that myself.
Does anyone have a clue as to what the problem might be? Are the pickups just plain dead (or dying)? I will probably try and take the bass into an Alembic dealer here in Korea (thanks to ajdover for the directions!) to see if they can diagnose and hopefully fix it, but would like to see if there are any ideas here first.
Also, the other major problem for this bass, at least for me, is that it has been defretted. I am not a fretless guy, so for me it's kind of useless like this. I suppose I could learn, but would really like to have it fretted again, if I can get a good deal here on a refret job. The fingerboard has some wear and the lines have been filled in with some red material (no idea what it is). Unfortunatley the fingerboard will never look great again, but I hope to at least make it playable with frets. I think it's rosewood but it could be ebony that's been sanded down a bit.
My question is this: Since the bass will have been defretted, then refretted again, could it cause too much "trauma", for lack of a better term, to the neck or fingerboard? It is a neckthrough bass, by the way. Is there a case where a refret job can not or should not be attempted? I suppose I could keep the bass fretless to try and learn on, but the point will be moot if I can't get the Alembic pickups working.
I wish I could post some pictures of the fingerboard and control cavity but my camera doesn't want to interface with the computer. Maybe I will be able to in a few days.
Thanks in advance for your help on this project.
Post Number: 4207
|Posted on Friday, March 02, 2007 - 5:59 pm: |
The good news is it's probably not the pickups. They are so simple, in almost every case they either work or they don't. So we're going to look at an electronics problem.
The first thing to try is the IC. You should see a small 8-pin chip on the same board with the trim pot. This is socketed, so you can change it to a new one without soldering, and do it yourself. The part number is TLE2022 or RC4558. You will probably have to take the filter out of the bass to get access.
To change it, just pull the IC out from the socket. When you plug the new one in, take note of pin 1. It will be marked with a notch, a circle, or a small molded numeral 1 near it. The socket will also be marked in a similar way. If you plug the chip in backwards, it will damage the chip, but nothing else. You'll have to try another one in that case.
Another note when looking at the chips is to not rely on the printed markings for alignment - these are not standardized. Only go by the position of pin 1.
Here's an example of the TLE2022 chip on a treble board:
When you reinstall the filter control, make sure none of the solder side of the board is contacting the side of the electronics cavity. You can hold the part in place with one hand as you use the nut driver with the other.
Ok, defretting and refretting. It all depends on the condition of the current fingerboard. A repair person will probably handcut new slots and relevel the board if there's enough room. We would just put a whole new board in place, which is also what a repair person would have to do if the board was too thin to take another levelling.
You'll have to defer to the expertise of the person doing the work to determine the health of the existing board.
Post Number: 30
|Posted on Friday, March 02, 2007 - 9:43 pm: |
Thanks for the speedy reply Mica. I took the bass, and your forum post, to the Alembic dealer in Korea (G-Cat) and they are going to work on the bass for me. It's not a serious problem at all.
When they plugged in the bass, it sounded fine - it apparently *was* the trim pot which was turned all the way up, which I must not have re-adjusted properly. My little practice couldn't handle the output. So that and some other adjustments and shielding will be done.
As for the re-fretting, G-Cat will also do that. He said it shouldn't be a problem to have done with the existing board.
Thanks again for your input!