Alembic Guitars Club

Alembic products => Owning an Alembic => Troubleshooting => Topic started by: tdukes on September 02, 2009, 06:54:50 AM

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 06:54:50 AM

This morning I was getting a loud hum from the neck pickup of my '77 Series I guitar with the 5 pin cable and no sound at all with a regular 1/4 jack. (I had previously wired the 1/4 jack for mono and used it successfully) The bridge pickup seems to be working fine. I used the guitar this weekend with no issues.
 
What should be my first step in resolving this?
 
Todd.

Title: Series I neck pickup problem.
Post by: lbpesq on September 02, 2009, 07:07:27 AM

Todd:
 
You might want to unplug the pickups inside the electronics cavity and swap them.  Then see if the problem switches to the bridge pickup or stays with the neck pickup.  If it stays with the neck, then the problem is with the pickup, if it moves to the bridge, then the problem is somewhere down the line in the circuit.
 
Bill, tgo

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 07:10:50 AM

Thanks Bill. I'll try that.
 
Todd.

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 07:33:16 AM

I took the back panel off. There are three coaxial cables marked red, blue, and black. I swapped the red and blue and replaced the panel.
 
The hum still occurs when the selector is in the neck position. I infer this means the problem is not with the pickup itself.
 
Todd.

Title: Series I neck pickup problem.
Post by: LMiwa on September 02, 2009, 08:13:47 AM

I would look at the points where the neck pickup lead connects to the circuit board.
 
Can you post a closeup of the circuit boards? Someone may be able to spot something or mark places to check.

Title: Series I neck pickup problem.
Post by: David Houck on September 02, 2009, 08:42:02 AM

Todd; when you say that you had previously wired the 1/4 jack, are you saying that you yourself did the work?  If this part of the circuit has been modified by someone other than Alembic, I would be inclined to check the modification; perhaps a bad solder joint, or a short between the lead for the neck side and the ground where they attach to the quarter inch jack.  Also, if done by someone other than Alembic, were the recommended resisters used, and do the resisters look good?

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 09:43:11 AM

I did the work myself. There is a picture in this thread. (http://club.alembic.com/index.php?topic=4907)
 
When I say there is hum on the neck pickup, that is all there is, hum. No signal. The bright switch, volumn, and filter change the character of the hum (60 Hz maybe), but no (or very little, inaudible) signal from the strings.
 
Todd.

Title: Series I neck pickup problem.
Post by: David Houck on September 02, 2009, 09:58:50 AM

Oh yes, I remember that thread now!  Did you move the resister leads away from the shielding and back plate?
 
Another quick check; is the pickup selector switch loose?  Could it have moved and have developed a grounding problem with the shielding?

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 10:01:33 AM

I did now (before I posted my last message). It did not help. The pickup selector seems very secure. I do not believe it has moved.
 
Todd.

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 11:16:05 AM

I have talked with Tony at Alembic. I am removing the PF-6 card and sending it to them for testing.
 
Thanks for all the help.
 
Todd.

Title: Series I neck pickup problem.
Post by: tdukes on September 02, 2009, 11:30:18 AM

I found an old thread where Mica said a PF-6 card was $350. Does anyone think that is not a good amount to insure one for when shipping it back?
 
Thanks,
Todd.

Title: Series I neck pickup problem.
Post by: David Houck on September 02, 2009, 01:37:15 PM

Let us know how it turns out.  I can't recall how much shipping companies charge for that amount of insurance, but I'm thinking the charge for $350 can't be too much, and it's certainly a good idea.  I have no idea what the current cost of a PF-6 would be.

Title: Series I neck pickup problem.
Post by: mica on September 04, 2009, 06:12:50 PM

Darn, Todd. The card tests out OK. Maybe you can email a few clear photos of the output jack wiring, and the electronics cavity in general.

Title: Series I neck pickup problem.
Post by: tdukes on September 05, 2009, 12:07:37 PM

I feared as much. I have taken some pictures of the electronics, trying to show the connections. I took pictures of the control knob as well, but they were all too fuzzy to be of any use. Let me know if they would help. The connections there looked good to me. If there are points I can check with a multimeter, I have one.  Let me know if you need additional pictures.  Thanks, Todd.  
(http://club.alembic.com/Images/394/69954.jpg)
 
(http://club.alembic.com/Images/394/69955.jpg)
 
(http://club.alembic.com/Images/394/69956.jpg)
 
(http://club.alembic.com/Images/394/69957.jpg)
 
(http://club.alembic.com/Images/394/69958.jpg)
 
(http://club.alembic.com/Images/394/69959.jpg)
 
(http://club.alembic.com/Images/394/69960.jpg)
 
(http://club.alembic.com/Images/394/69961.jpg)
 
(http://club.alembic.com/Images/394/69962.jpg)
 
(http://club.alembic.com/Images/394/69963.jpg)

Title: Series I neck pickup problem.
Post by: mica on September 08, 2009, 03:13:44 PM

Thanks for posting these pics. My dad is going to take a look over them tonight. I'll let you know if he's got any theories after that.

Title: Series I neck pickup problem.
Post by: mica on September 09, 2009, 12:59:15 PM

So there's nothing obvious, but my dad went ahead and replaced the FET on the bass pickup channel on the preamp card since it's a possible cause of the problem if it's intermittent it oculd test fine here and work fine for you until it doesn't.  
 
We'll send the card back to you today and you can tell me the results once you reinstall.

Title: Series I neck pickup problem.
Post by: tdukes on September 09, 2009, 01:18:14 PM

Thanks Mica!  I'll let you know when I get the card and reinstall it.
 
Todd.

Title: Series I neck pickup problem.
Post by: terryc on September 15, 2009, 02:50:27 PM

Would Mr Sony repair your dvd/camera/tv etc.
Having the BOSS repair your gear is priceless!

Title: Series I neck pickup problem.
Post by: toma_hawk01 on September 15, 2009, 04:09:27 PM

This is why I love this organization in more ways than one.

Title: Series I neck pickup problem.
Post by: tdukes on September 15, 2009, 05:34:55 PM

Mica, your dad has great insight!!
 
I received the card today in the mail. The neck pickup appears to be working for me. At first I was horrified by the amount of distortion, but realized that the gain had been turned all the way up on the PF-6 card. This sounds great on my Fender Twin Reverb, but not so good on my practice amp. I guess it just doesn't have enough headroom.
 
After adjusting the knob down about halfway it sounds great through both the practice amp and the Twin Reverb. Man, this is a great guitar.
 
Thanks again Mica, and tell your dad thanks as well.
 
Also thanks again to Sam for selling this guitar to me (I hope you are not too sad)
 
Man, this is a great guitar.
Todd.

Title: Series I neck pickup problem.
Post by: tdukes on September 15, 2009, 05:44:08 PM

I had just about had my wife talked into the electronics upgrade and a refinish if I were to have had to send the guitar there to be fixed.
 
Todd.

Title: Series I neck pickup problem.
Post by: David Houck on September 15, 2009, 06:07:18 PM

Congrats Todd!!!