Beware ! You're in Kamikazie here. Not many pro luthiers around, more often brave souls experimenting in their kitchen.Golden Tone and "Hershey bar" pickups re-born - by François
For those of you who never had a look inside a pickup, I remind that the gauge used for the wire is very, very thin, really like a hair... You can't have a drink before working there... But you can attempt this before rewinding if you have a dead pickup.
Golden Tone "Indox"
I recently had a very nice experience in giving a second life to a "golden tone" pickup (from a H66 Vibrajet). After some testing, I suspected that the ground side of the coil had a bad electrical contact with the metalic base plate. In the Golden pickup, the tiny wire is soldered directly on the plate, see the photo. I just had to gently touch the old solder with the soldering iron, and voila, the pickup had its nominal resistance (12k if I remember), and the guitar was rockin some minutes later...
I wonder how many of these pickups in our guitars are weak and just need the gentle iron touch... to go back to strong and gold tone !
"Hershey bar"
I had a "Hershey bar" bridge pickup from a Silvertone that was very weak in output and sound, compared to its neighbour from the neck.
After removing the pickguard and unsoldering, I measured the pu's : some 3.5k ohms for the neck, and some "variable" 40k or nothing for the bridge (I read here on this forum that 3.5k is the normal resistance for these kind of pu's).
After dismantling the Hershey from the Silvertone, it was a different story from the Golden tone above : no visible soldering of the inner side of the coil... The more I was opening the pickup, the less resistance I had, to a completely open coil at the end... I was scrutering the thing and touching everywhere to locate anything, and at a point I had a low resistance again ! I understood the problem was (again) the inner end of the coil, having a bad ground connection. But how to repare the connection *inside* without un-wounding the coil ?
I made a choice : to cut one of the very inner coil, and routing it directly to the ground connection of the outer wires, on the base plate... This way, I loose some of the inner turns, but very few of them I believe, by choosing a turn very close to the magnet. Check the photos below.
The coil is wounded counter-clockwise (like the red schematic), because of the outer end connection. So I choosed the place where to cut the wire, to have enough length to route it to the soldering point.
I had first to remove the enamel from the wire, to be able to solder it. Hence the sanding paper... It's a 600 grade water sanding paper.
First photo shows where I cut and sand the wire (red arrow shows where I sand and put some solder before cutting).
Second photo shows how I carefully routed the wire to ground (parallel to the red line).
And you guess what... 3.5k ohms and a strong sound like new :)
The brown stuff on top is some adhesive residue from the mylar foil carefully removed, (and later replaced with similar material, cut from a sleeve in a photo album.. old adhesive was enough to maintain it in place..)
august 2005
back to Kamikazie Lutherie Index |
