'76 4001 wiring problem

[pdusen]

I have a 1976 4001 that I need some help with. There's some kind of problem with the wiring that I'm having trouble tracking down; I know the pickups are connected because I can hear it through an amp when I tap on the pole pieces with a screwdriver, but the only other sound coming through the amp is a fairly constant buzzing; the strings vibrating hardly makes a sound at all.

I just got this bass a few years ago and it had already been heavily modded before it ever got to me, so I have no idea how much of the wiring that came with it was even original. I recently had it refretted to actually be playable and refinished (the original finish was long gone, and the finish it had when I got it was... not very good).

I know when I originally got it it at least made sound through an amp. I'm guessing whatever problem occurred was introduced either when it was being reassembled after being refinished, or when I opened it up to try and fix a problem I was having adjusting the neck pickup (I, of course, was a moron and didn't actually plug it in prior to doing this, so I have no idea if I caused the issue or not).

Photos are attached; I'd appreciate any insight anyone might have on what the problem might be, or what steps I can take to try and narrow down the problem. I've done some basic guitar wiring in the past but this is a lot more complicated than what I'm used to, and I can't make heads or tails of wiring diagrams. I do own a multimeter but I don't have a great understanding of how to use it to diagnose wiring issues.

[Dirk]

If I were to guess those grounds on the back of the pots don't look that great.
Looks like some excessive heat's been used. It might be worth re-melting those.
Also worth checking and reflowing the pins on the pots too.
Just check to make sure all connections are solid.
The 3 way selector switch can cause all kinds of problems, worth checking those too.

Also of note, there's a ton of wrong or flawed diagrams on the web, might as well go to the source.
http://www.rickenbacker.com/pdfs/19507.pdf

Good luck,
Dirk

[ram]

what Dirk said and look at the bridge ground wire and the ROS jack switch as well. I'm betting on the pickup selector switch or the ROS jack... good luck with it. Keep us posted.

[jdogric12]

Excessive heat can fry pots too, right? For the short time I was getting taught how to do my own soldering I remember being told that - not to hold heat near all that stuff and especially in contact with metal since it transfers heat very efficiently and fries stuff.

[espidog]

Looking at those pictures, yes, most of the ground connections from the pickups to the pot bodies have been badly done. Those are not good solder joints. The only decent ones I can see are the one for the bridge grounding wire (most likely done in the factory) and the one on the back of the bridge pup tone control. The rest are rubbish.

Not wishing to drag this thread off-piste, and purely for the benefit of those who may not already be aware, but this seems a good opportunity to offer a few words on the subject of overheating components when soldering:

Overwhelmingly, the main cause of this is using a soldering iron that isn't powerful enough. You want to create a small pool of solder on the back of a full-size, metal-bodied pot and you've only got a measly 15-25 Watt iron? Good luck! You'll be pressing that thing (with its no doubt too-small tip) onto the metal for a loooong time, hoping to get that one area up to solder-melt temperature, but the problem you've got is that the energy you're putting in is being soaked up into the rest of the component faster than the iron tip is able to supply it. Result: by the time you do get that solder area to melt (if you ever do), the whole damned pot is at a high temperature and its internal gubbins (technical term) has got nicely broiled.

Low wattage irons are meant for working on fiddly, delicate solid-state circuitry, not old-school chunky guitar pots. Do yourself a favour: buy a 50-75 Watt iron. To get the solder to pool, the correct method is to apply a LOT of energy very briefly to a single point. It's like spot-welding. Do this, and immediately the solder will melt and flood - literally in a second or so. Then remove the iron, and the solder will solidify instantly to a good, bright, shiny joint, because the heat you applied to that small area has already begun to dissipate. Job done.

ADED LATER: Obviously, it's horses for courses. If you're soldering the tags of a miniature toggle switch, use a low-wattage iron with a fine tip. For full-size pots and jack sockets though, fire up the big fella.

[jps]

Looking at those pictures, yes, most of the ground connections from the pickups to the pot bodies have been badly done. Those are not good solder joints. The only decent ones I can see are the one for the bridge grounding wire (most likely done in the factory) and the one on the back of the bridge pup tone control. The rest are rubbish.

Not wishing to drag this thread off-piste, and purely for the benefit of those who may not already be aware, but this seems a good opportunity to offer a few words on the subject of overheating components when soldering:

Overwhelmingly, the main cause of this is using a soldering iron that isn't powerful enough. You want to create a small pool of solder on the back of a full-size, metal-bodied pot and you've only got a measly 15-25 Watt iron? Good luck! You'll be pressing that thing (with its no doubt too-small tip) onto the metal for a loooong time, hoping to get that one area up to solder-melt temperature, but the problem you've got is that the energy you're putting in is being soaked up into the rest of the component faster than the iron tip is able to supply it. Result: by the time you do get that solder area to melt (if you ever do), the whole damned pot is at a high temperature and its internal gubbins (technical term) has got nicely broiled.

Low wattage irons are meant for working on fiddly, delicate solid-state circuitry, not old-school chunky guitar pots. Do yourself a favour: buy a 50-75 Watt iron. To get the solder to pool, the correct method is to apply a LOT of energy very briefly to a single point. It's like spot-welding. Do this, and immediately the solder will melt and flood - literally in a second or so. Then remove the iron, and the solder will solidify instantly to a good, bright, shiny joint, because the heat you applied to that small area has already begun to dissipate. Job done.

ADED LATER: Obviously, it's horses for courses. If you're soldering the tags of a miniature toggle switch, use a low-wattage iron with a fine tip. For full-size pots and jack sockets though, fire up the big fella.

Let's add in the "charm" of working with the devil's solder (lead-free).

This should take care of anyone's soldering requirements!

[pdusen]

Also of note, there's a ton of wrong or flawed diagrams on the web, might as well go to the source.
http://www.rickenbacker.com/pdfs/19507.pdf

Yeah, I've seen that diagram before. Unfortunately, it might as well be Greek, for all the sense it makes to me.

It may be moot anyway... quick update, today I took the bass to a guitar tech in my area that I've been assured has a lot of experience with RIC guitars and basses. Hopefully he can get the whole thing sorted out in a few days and then I don't have to worry about this anymore.

[espidog]

Let's add in the "charm" of working with the devil's solder (lead-free).

Quite. Not what I'd call an unalloyed pleasure.

See what I did there? See? "Unalloyed", geddit? Damn, I'm on form today...

[pdusen]

Good news; the tech I went to figured everything out. I picked the bass back up today and everything seems to be in working order.

He concurred with you guys about the wiring being really sloppy. The things he ended up doing included:

- Cleaned up sloppy wiring
- Added two inter-pot ground wires
- Replaced the mono jack in the rick-o-sound position with a proper stereo one (I wasn't even aware this was a problem!)

Overall I'm quite happy with the state it's in. I'll post more about the instrument later.

[Dirk]

Awesome, now get playing!

[ram]

SWEET!!! Sounds like you are set!

[espidog]

Excellent news - glad you got it sorted by someone who knows his stuff.