So, I finally decided to try refurbishing the electronics in my 1977 3001. I ordered new pots, caps, and 1 resistor, all according to the official Ric schematic. The sound after installing everything was BAD. No effect on the bass tone at all. Something made me check the caps I had removed and they are not what is shown on the schematic! It shows both caps (marked C1 and C2) as .047. I assumed that means .047mFd for both, so that's what I ordered - great big orange ones - they barely fit in the cavity! These new ones check exactly .047mFd on my meter. The ones that came out, however, check .001mFd for C1, and .1mFd for C2. What the #$%!!! I put those caps back in along with the new pots and voila! Everything went back to normal. So, I'm wondering, should I buy some new caps with the same readings as the originals? Or should I assume that C1 is supposed to be .0047 and C2 is supposed to be .047? Or just leave well enough alone. I've also been reading alot about "magnet fade" in these old instruments so my next project might be to try refurbishing my spare pickup. I'm just really confused about these caps and why the schematic seems to be wrong. Any thoughts?

What are the markings on the caps you took out? They usually say what their value is. It is possible for old caps to change value over time. It's also possible that someone changed them to non-stock values (assuming you didn't buy this bass new).

@cjj: I did buy the guitar new and no one has worked on it but me. The C2 cap is white on the pin end, then red, white, yellow, black, and brown on top. I found one chart that (if I was reading it correctly) said the white stripe would mean it was 0.1mFd - exactly what it measures. The C1 cap is a little tiny thing that is dark green all over with some numbers on it I didn't try to look up - I'll write them down next time I mess with it. Those readings seem so odd compared to about everything else most guitars use...and Ric's own schematic. I've got a .047 and a .0047 Orange Drop, so I'm going to try them in there and see what happens. I'll probably order a 0.1 and a 0.001 just to play around with and see if I can tell the difference. I don't mind experimenting with it but I get antsy when I can't play it, even though I've got three other basses!

The markings on the (little green) C1 cap are: EDI on one side, and .001k 100TSC on the other.
The "k" kind of throws me but I don't think I've ever seen caps called out in KiloFarads. If it means .001uFd then my measurement is correct. I'm leaning more towards that, so I'll probably get new .1uFd and .001uFd caps just so I know everything in there is fresh. On to rewinding and re-magneting the pickup!

Yes, that is a .001uF capacitor, the k means 10% tolerance, not kilofarads.

Caps are usually marked with either microfarads (uF) or a code denoting picofarads (pF) the the pF codes it is 2 digits of values the a digit for an exponent. So, 103 would be 10e3 or 10000pF (10nF or .01uF).

Interesting! Do you think I analyzed the stripes on the C2 cap correctly? I came up with it should be .1uF. On another note, on pickups: In a previous post someone commented that this pickup is epoxied and it is not. I was looking at replacing the magnets, but apparently they can be "recharged" using neo mags. If so, does anyone know what the gauss reading should be? It looks like it's pretty simple (and cheap) to build a gauss meter with Arduino.

Cap colour bands are sometimes confusing since it makes a difference which way you read them. I would guess that yours starts with the brown end so you would have:
Brown = 1
Black = 0
Yellow = 4, or 4 zeros

So, 100000pF which is 100nF or 0.1uF.

The white means 10% tolerance, red is a voltage rating which depends on the actual type of cap. That doesn't really matter for guitar circuits, but is probably either 250V or 300V.

I have found no tonal change noticeable on my Ric bass with changes in just tone pot and cap values.

I have learned that the most dramatic way to change the sound of a bass is with changing the VOLUME pot value and/or the PICKUP.

I did a 1MEG VOLUME pot with toaster pickup. So bright and clear now, but still has all the low end and mids.

So, after looking into rewinding my pickup I found a lot of stuff about recharging the pickup magnet. I bought two powerful neodymium magnets on Amazon (3" x 1/2" x 1/2" - about $17 each) and downloaded a decent gauss meter to my phone (yes, for FREE!). I wasn't so much interested in the actual reading on the gauss meter as the change from before charging and after. It looked like about a 30% increase in magnetic flux after charging. This produced a VERY noticeable increase in the output of the pickup and it seems like I've got my great sounding and powerful bass back! I don't have to run the volume twice as high as with my P-bass or 5 string Yamaha anymore; they all have very similar outputs now. I guess I should have tried that first, lol. Oh well, the whole project has been a great learning experience and I don't mind what I've done. I still want to do some shielded wiring and cavity shielding, but it seems that even the hum is greatly lessened, probably because I don't have to turn it up so loud now. I may play around with a different volume pot and I still need to replace the caps with the new ones I bought. I wish Rickenbacker would correct / update the schematic for this bass to show the correct caps!! They are NOT 0.047 like it says!! They are 0.001uF for C1, and 0.1uF for C2. It kind of makes you wonder how they produced these basses in the first place if the schematic is incorrect??? I notice the date on the schematic is 1991, so since these basses were discontinued in 1979(? or thereabouts) it's likely that the schematic was redrawn or digitized at some point and there was simply a mistake made.