Tech help! 4001 neck p/u, dead.

brycycle · Post by **brycycle** » Sat Dec 23, 2006 1:34 pm

i just picked up a '75 4001, when the switch is in the neck p/u position, there is no sound, no noise when tapping the poles.

when in the central position (both p/us) the bridge p/u works, if tapping the poles of the neck p/u, it can be heard.

i opened it up and referenced it to my other 4001. all looks good, i re-solderd most of the connections and noticed that the 0047 cap has been replaced with a straight wire.

the jack was scratchy - just seemed dusty.

any ideas?

thanks.

brycycle · Post by **brycycle** » Sat Dec 23, 2006 2:36 pm

sorry, switch that around, the issue is with the bridge p/u.

stts64 · Post by **stts64** » Sat Dec 23, 2006 2:49 pm

So you know that the pick up works when in central position (both pick ups on). Could it be the selector switch problem then?

soundmasterg · Post by **soundmasterg** » Sat Dec 23, 2006 2:56 pm

Unsolder the wires for the bridge pickup from the switch and measure them with a DMM set on resistance. You should get a reading of somewhere around 8k to 9k. If it is really low then the coil is shorted and needs to be rewound. I had this problem with my old '73 4001, and I sent the pickup to TVJones to rewind. It is rather common on 70's RIC's. He did a very nice job, and matched up the pickup perfectly to the neck pickup. Lots of other winders could do this including our very own Sergio if that is what needs to be done.

If you get a good DCR reading, but it still doesn't work when hooked up, then there is something wrong with the switch most likely.

brycycle · Post by **brycycle** » Sat Dec 23, 2006 4:18 pm

i was a little hasty in my diagnosis; it seems the bridge p/u is flat out dead. i'll see if i have a DMM.

if not, i'll be pleading to Sergio. he helped me in the past and totally saved the day.

update to come...

rickenbrother · Post by **rickenbrother** » Sat Dec 23, 2006 5:07 pm

Bryce, are you certain that it is not the switch, output jack, or a disconnected wire?

brycycle · Post by **brycycle** » Sat Dec 23, 2006 5:30 pm

joey, what would i look for in the switch? the contacts are contacting.

i re-soldered the ric-o-sound jack connections, all the other connections.

rickenbrother · Post by **rickenbrother** » Sat Dec 23, 2006 5:40 pm

Bryce, you would check the switch for proper contact, dirt or corrosion, but seems you have done that already. Have you just for the heck out it, plugged into the Rick-O-Sound jack? You would hear the the bridge pickup only with a regular guitar cable when you do that, if the pickup is okay. If you hear nothing and can't find a meter, just hold the unsoldered pickup wires to a guitar cable, plugged into an amp. Put the hot pickup lead to the tip, ground to the sleeve. If you hear nothing when you tap on it, the pickup is dead. You'll also want to make sure there isn't a wire disconnected going into the pickup assembly.

johnallg · Post by **johnallg** » Sat Dec 23, 2006 5:45 pm

Good suggestion, Joey.

rickenbrother · Post by **rickenbrother** » Sat Dec 23, 2006 5:48 pm

John, you are the best at spotting disconnected wires, especially on pickups!

brycycle · Post by **brycycle** » Sat Dec 23, 2006 6:24 pm

Joey - thanks for the tip on testing w/o a meter. i found one; but the battery was dead and i didn't have a 9V around.

i tested it w/ the guitar cable and nothing. to ensure i was testing properly, i did the same test on one of my fully functioning 4001's and i could hear the tapping through the amp.

looks like i put out an emergency call to Sergio!

thanks for your help in the diagnosis.

rickenbrother · Post by **rickenbrother** » Sat Dec 23, 2006 6:45 pm

You're welcome, Bryce.

Sergio recently revived the neck pickup of my 4001S. Man, does that bass rock now!!

s4001 · Post by **s4001** » Sat Dec 23, 2006 6:52 pm

Hey! That's good news. A very deserving bass, indeed.

rickenbrother · Post by **rickenbrother** » Sat Dec 23, 2006 7:05 pm

Scott, yeah that bass deserved to have the pickup fixed. Now I have to make up my mind if I want to refinish it or not.

brycycle · Post by **brycycle** » Sat Dec 23, 2006 7:30 pm

yeah, Sergio is fantastic at what he does, and extremely helpful and accommodating to forum members; a stand-up guy.

this will be my favorite ric when fully functioning, white '75 with black plexi TRC, i noticed the 0047 had been bypassed, think i'll return it to it's original vibe.