bridge pickup no sound. lots of crackling sounds

[dslapster64]

Hi everyone, it's me with the old 1979 series one. All of a sudden the bridge pick up is not working. Coupled with lots of crackling as well. So I took the back cover off and found that one of the plugs was disconnected, so I did connect, but for some reason it is still not working. On looking at it and the circuit, etc. obviously it's very old and I'm not sure if it's just simply worn out. Let me know what you all think, and I'm open to any suggestions. My guess is that the whole circuit is probably the original one from 1979.

[JimmyJ]

These circuits typically don't "wear out".  Although components can fail it's pretty rare.  More typical is that the pots and switches all need to be exercised about 50 times.  If they haven't been moved for years they can stop performing correctly. But sweeping the pots and switching the switches can often "wake them up" and return them to proper service.  Give that a try before anything else.

Jimmy J

[dslapster64]

I've definitely tried that a few times. However, it was working fine earlier on in the day. I am wondering if some soldering may have slipped off. I'm gonna take a look again inside to see what's going on.

[edwardofhuncote]

David, since your pickup selector switch has been moved, you might verify that nothing is loose on the switch itself that's preventing continuity. I want to include the clear disclaimer that my Wire Dunce Credentials are clearly established here.   


Just seems like something I'd do...

[dslapster64]

lol . I am looking into all that as we speak. Love you guys.
David

[dslapster64]

@Jimmyj
So I swapped around the bridge and neck pick up plugs and definitely. And the neck pick up work just fine. So it appears to be the plug itself or the wires that attached to the plug. Does Alembic sell those plug connectors? Or are they automatically connected to the pick ups? Any other ideas would be appreciated. What say you.?

[rv_bass]

I don’t recall seeing those two big gray resisters on any of my Series basses, but I could be wrong.  I’m wondering what it says on the tape on the cavity lid?

Make sure that the 14 pin connector is secure.  Maybe also check where the wire inserts into the molex connector to make sure that is still a solid connection. 

Are you using the 5-pin or 1/4 jack? Does the problem happen with both?
 

[dslapster64]

@rv_bass
I don't see anything loose except the plugs and connectors themselves. The result is the same either using a quarter inch or the five pin. I'm going to have a tech guy look at it tomorrow, and hopefully it's not a big deal. Just hoping to get something very simple that I'm not able to see myself.
 

[JimmyJ]

The larger gray caps are an unusual sight but I believe that to be factory work possibly due to an interruption in standard component supplies...  Just a guess.

So by swapping the pickup plugs you've determined that the bridge pickup is the problem, right?  The neck pickup sounds fine in either input?  That calls for a close inspection of the bridge pickup connector to be sure there isn't a loose shield wire somehow shorting the two conductors.  Then follow the wire to be sure it hasn't been pinched somewhere on the way to the pickup.  Last place to look is the underside of the pickup to be sure it hasn't been yanked away.

But really, as e-of-h mentioned above, if all worked fine before you moved your pickup selector then you need to be sure nothing is touching those exposed switch terminals. 

And a special request: if you're on a Mac and an iPhone, please import those HEIC pics into the Photos app and then export them as medium sized jpegs.  Then your attachments should appear in the thread as opposed to "downloadable" only.

Keep us posted.

Jimmy J

[dslapster64]

Hey JimmyJ
Thank you so much for that advice much appreciated. I will definitely keep you posted
David

[mica]

I showed those big capacitors to my dad and he told me they weren't one we used so they are replacements.

If you have a problem with the crimped end of one of the pickups, we can get you a short length of wire pre-crimped that you can splice on and seal up the splice with shrink tubing.

Looking forward to the pickup selector report - include pics if possible.

[dslapster64]

Thank you Mica
I would that if possible. My tech is working on the bass now. Once o get the pickup selector done I will be sending pics.

[dslapster64]

Mica, do you think the capacitor changed makes any significant difference with the sound or quality of the bass?

[dslapster64]

OK so my tech is working on my series one, and he asked this question:

"I notice this brown wire that is cut or broke on the ribbon cable. I don’t see the broke off piece anywhere. Can you reach out to Alembic and see if this is supposed to be cut? "

[dslapster64]

Sorry, let me try and send that picture again.. stay tuned