#1
Hello,

Last year, I purchased a 1977 Kramer 450g. Ever since I've had it, there's been a problem with the knobs. I don't go out and play gigs with it, so it's never been too big a deal, but I've finally decided to do something about it. However, I am new to modding/repairing guitars and was hoping for some assistance.

The problem is that both the volume and tone knobs make scratchy noises through the guitar signal when I turn them (the volume ones especially). On top of this, when I turn the volume knobs down to zero, the guitar signal still comes through, and sound more like you turned it down to around 4.

I'm thinking I'll just replace all the potentiometers and start fresh. However, I do not know what parts I will need in order to do this. I know I should use 500k pots, but that's the only detail I know.

I have attached a couple photos of the inside of the back plate for reference. I also was able to find this diagram that claims it's to a 1978 Kramer 450g, but it seems a little different from what I see in the guitar:
http://s61.photobucket.com/user/nopicknick/media/kramer-wiring/1978_450G.gif.html?sort=3&o=22

Any help with this issue would be most appreciated.

Thank you very much
Attachments:
zzz1.jpg
zzz2.jpg
Last edited by PerpetualOyster at Feb 21, 2015,
#2
over time potentiometers accumulate dirt, there is some sprays and cleaners out there you can get at electronics stores. I'm not sure what the industry standard is on here but that will answer question 1. You spray the can into each potentiometer and you're good to go. Just twist the knob back and forth a few times to ensure that all the dirt goes out of the pot.

ok so question 2.
check the wiring, not properly going 10-0 I would think that it would be the ground wire isn't properly soldered or it's a cold solder no sense in putting a new potentiometer in just yet. Try and repair the connections yourself first not much goes in to a volume pot.

so staring at it from the cavity still attached with the washer and nut
left - hot lead - signal in - this is to the switch on this wiring
middle - wiper - this controls the % of sound going out of the guitar
right - ground - signal out - this goes to the top of the volume and wires from pot to pot ground it out

everything on the top of the volume is ground, you could have two blobs of solder. One for the main wires you never want to de-solder and another for the pickup ground. Wiring diagrams if needed I suggest the seymour duncan wiring website.

so if you do really want to switch the pot B500k I suggest. However play a few guitars and see what you like best. I find A500k you can't practice at low volumes as good and you lose a lot of highs at like 8 or 7 so the sound isn't consistent. The good news is regardless of what you go with 10 is 10 and 0 is 0. Just how they react. Average sized pots you'd want by the way.

I'd have fun with this and put a push pull or something in the guitar though. But it's your guitar see what you want to go with. Anyways any questions send me a message.
#3
Deoxit is the brand usually considered best, IF you have a Radio Shack still open locally they sell a house brand that works fine. You can also get it at auto parts stores.

If you want to replace the pots, an Audio taper is usually used for volume, it has a more gradual sweep as you turn it. Linear taper works fine for tone. Take pictures before removing anything, I usually also draw a wiring diagram telling me what color goes where. Replacement probably won't be necessary, some contact cleaner and work it from 0 to 10 a dozen times should do the trick.

If it's still not turning down all the way, then replace the volume pots.
Hmmm...I wonder what this button does...
#4
Thanks for the replies so far.

One thing I forgot to mention was that I actually did have someone clean the pots a few months ago. That did get rid of most of the scratching, but it's still going on. Not sure if trying again would be of use or not, but I'll probably try that.

As for the possible connection issues raised by Tallwood13, I will definitely looks into this, as I hadn't really considered it before. Once I am able to get some soldering done, I will get in there and try making sure everything is properly connected.

And thank you both for the pot replacement advice. I think I know now what I'll need if it does come down to that. My only question left with that is if anyone has any suggestions as to where I should buy new pots if I need to?


Thanks
#5
Any guitar parts website should be fine. Avoid allparts they are very over priced.

stewmac comes up a lot - their selection for other stuff is a plus
guitarelectronics.com for more advanced stuff. push pulls, mini toggles..etc.

kind of like buying groceries from various super markets most carry the big brands just shop around and see who has the best prices. I'd look for CTS or bournes potentiometers I recommend. CTS is what Fender uses a lot and bournes is just as good from all the years of googling. I have a blog about finding the right pots but the jist of it for values are..

humbuckers with less than 500k - darker
humbuckers with more than 500k - brighter (you can turn a pot down for darkness)
tone pots with a higher resistance (500k vs 250k) = less sensitivity , of course smaller capacitors can compensate for this.
Last edited by Tallwood13 at Feb 22, 2015,