Author Topic: Big crackles in the neck pickup circuti - Series 1 '78 (Read 560 times)

garth4664 · « **on:** September 13, 2009, 01:39:23 AM »

Big problem please help.

My neck pickup circuit started making loud intermittant crackling sounds at a gig last night. Fortunately could switch to the bidge and complete the gig.(When I turned down the neck pickup volume or switched the neck pickup off there was no crackling at all and the bass sounded as usual.)

I have had a chance to investigate the issue today - it is really strange. Generally speaking if i sit still and turn the neck pickup volume adjustment trim pot (on the back of the insrument) the crackling goes away and the neck pickup sounds clear. But if I get too vigourus or tap the back brass cover the crackling can come back (it is not the same result everytime).

I opened the back of the bass and noticed that if I tap the components on the circuit (card) I get a crackle with each tap.

Swapping the pick ups does not change the issue, I.e. the neck pickup works very fine with the bridge pickup circuit and the bridge pickup crackles through the neck pickup circuit. so the issue seems to be in the circuit (card) rather than the pickups themselves.

Mica is this something that I need to send the circuit board back to Alembic's factory to fix?

Are there any further tests I could run?

Please help,

Garth

slawie · « **Reply #1 on:** September 14, 2009, 03:06:20 AM »

Hey Garth sorry about the problem nothing worse that your
Alembic sounding sh!tty.

Check connectors that they are seated properly.
And also a simple thing is to run an pen eraser
(one of the rough ones - not pencil kind) on
the pins of the
connectors to lightly rough up the metal thereby cleaning the surface.

You can get one of those jewellry eye pieces
and check for dry or cracked solder joints
and or connections. I am an old fart and need one of these.
Any of you young folks can probably see it with the naked eye.
Look at the points where components or sockets
are connected to the PCB (printed circuit board)
Look for discloloured or not shiny joints or
a blackline around the component solder interface.

If you find any of these, solder it/them up,
or if you don't trust your soldering skills, find someone who can.
Or send it back to Alembic.

It might not fix the problem but it's a good place to start.
Sorry if I am repeating something you aleady have tried.

slawie

garth4664 · « **Reply #2 on:** September 21, 2009, 04:10:54 AM »

Thanks Slawie,

Tried all of the above - nothing out of place on the soldering side, and bass plays perfectly if I remove the PF6 and just let it dangle from the leads in the breeze with the back plate removed.

I think it is a faulty component, simply because where there is no vibration there is no noise, but perhaps it is an unobvious solder connection.

I've written to Alembic help email asking whether I should send the PF6 through to them. Hopefully it won't take them too long to repair and send back to me

Life without a series 1 is going to be pretty tough. Will have to stay away from tall building windows and sharp objects.

Thanks for all the advice.

Cheers,

Garth

tdukes · « **Reply #3 on:** September 21, 2009, 05:36:32 AM »

It took about a week and a day or so for me to get mine there, fixed and back again. My total cost was a little over $50. I guess the cost will depend on what's is wrong with your card and how you ship it.

My problem was a FET, sounds like you may have a bad trim pot.

Good luck,
Todd.

garth4664 · « **Reply #4 on:** October 02, 2009, 06:56:18 PM »

2-3 weeks after writing the email to Alembic help still no reply. Not sure if I should just send the PF6 card back or not - will Alembic look after it if it arrives unannounced?

David Houck · « **Reply #5 on:** October 02, 2009, 07:02:51 PM »

Try giving Mica a call. Probably the best time would be between 10 and 4 pacific time.

mica · « **Reply #6 on:** October 02, 2009, 07:54:23 PM »

Garth, I did not see your email. You can send the card in no problem. Make sure you send it in a static-safe bag, then packed in a sturdy BOX (I will actually be mad if it arrives in a padded envelope, and you don't want to see me mad). Include a note with:

-your name and return address
-phone number/email to contact you about the repair
-serial number of your bass
-description of the problem you observed
-what troubleshooting you attempted first

There's a $75 cap on PF-6 card repairs. Shipping is additional. BTW, you should insure the card for $350, since that's the replacement value of a new one.

garth4664 · « **Reply #7 on:** October 03, 2009, 06:54:41 AM »

Hello Mica,

Thanks so much - will send via hong kong express post as instructed. I will also send all the details as requested - will be so good to have the series 1 fixed...can't wait.

garth4664 · « **Reply #8 on:** November 23, 2009, 08:59:13 PM »

Hello Mica, Any word on this - has the PF6 been repaired yet?

Kindest regards,

Garth

mica · « **Reply #9 on:** November 25, 2009, 10:26:15 AM »

I am not in the office today, sorry I missed this message on Monday, but I believe it's complete and ready for return shipment. I'll check on Monday and let you know.

(Message edited by mica on November 25, 2009)

garth4664 · « **Reply #10 on:** December 01, 2009, 09:43:36 AM »

Hello Mica,

Thanks - please feel free to charge my credit card (details as provided earlier) and send back to my office address. Thanks again for all your help , can't wait to play the old girl at my next gig.

Cheers, Garth

garth4664 · « **Reply #11 on:** December 01, 2009, 09:49:23 AM »

Hello Mica,

Thanks - please feel free to charge my credit card (details as provided earlier) and send back to my office address. Thanks again for all your help , can't wait to play the old girl at my next gig.

Cheers, Garth

garth4664 · « **Reply #12 on:** December 10, 2009, 07:00:57 AM »

Hello Mica, any word on this? Has it been sent yet? would love to get the 78 coco sounding again...

garth4664 · « **Reply #13 on:** December 19, 2009, 05:16:24 AM »

Mica, I heard from Mary that the Alembelectrictricians couldn't figure out what is wrong with the circuit board - any news??

garth4664 · « **Reply #14 on:** February 06, 2010, 06:01:47 PM »

Hello Mica,

Sent an email - is this ready to be sent back yet?

Any news?

Cheers,

Garth