Gallien Krueger 800rb help?!

kyle_saville · #1 07-08-2010, 07:47 PM

I have an older model 800rb, and recently the low channel started giving me a lot of trouble. When it was plugged into the low output it would go to low volumes, crack, distort, and cut out. When tapping to low master switch it would cut back in and out, so i think the problem is the low master pot. I bought some deoxit and cleaned all the pots and it didn't help the problem. and the amp works fine on the high channel. So here's my questions, would replacing the pot be worth doing, how do you replace the pot, and what kind of pot do i need???

thanks

lbwdog · #2 07-08-2010, 08:12 PM

Try tightening all the nuts around the amp's output and input jacks. I had a similar situation with my 800RB, and lo and behold, one speaker jack had gotten loose.

Also, read through this thread.
http://www.talkbass.com/forum/showth...t=#post9332659

**B-string** · #3 07-08-2010, 08:15 PM

Yep the effects return jack caused this trouble once with mine.

Montanamike · #4 07-08-2010, 08:15 PM

I really don't know the answer to your question specifically even though I do own an 800rb I have never had any issues with it. Never even had the cover off.

From just a practical point of view. It the pots are board mounted it could be a variety of issues but if they are individual changing the pot is pretty simple. Just unsolder the old and replace with the new. The pot parimeters or stamped on the pot.

Better yet call Brian in tech support at GK and get his opinion, he's great.

kyle_saville · #5 07-15-2010, 05:03 PM

so i tightened all the inputs and outputs and it's still doing the same thing, any other advice???

jelwood · #6 07-15-2010, 05:05 PM

Did you take B-string's advice and clean the effects return? I've heard this story more than once with the 800rbs and the effects return is notorious for causing the problems you describe.

kyle_saville · #7 07-15-2010, 05:10 PM

yea i used deoxit on it

kyle_saville · #8 07-15-2010, 07:56 PM

found this strange, i took the know and the nut off the switch and it started working again???!!?!? can anyone explain this

Foz · #9 07-15-2010, 08:40 PM

post a pic

Gubna · #10 07-15-2010, 10:24 PM

I had two of these early models. My first one I purchased in 1991 - in 1993 I had some issues with it, and took it in to a local amp repair guy (hal at Guitronics in SF). He said all the factory sodering was shite. He re-did all of them and i never had any probems with it again up until I sold it in the early 2000s.

m-troniks · #11 07-15-2010, 11:42 PM

Sounds like cracked solder joints on master volume or a bad pot.
should be a simple fix for your local repair shop, or if you have a soldering iron resolder the three legs of the master volume pot and see if it works

kyle_saville · #12 07-17-2010, 05:25 PM

thanks guys but i resoldered the pots and still didnt fix the problem so i figure it has to be a bad pot. i removed the solder and took out the master low pot, does anyone know a good site to order a replacement for it???

**B-string** · #13 07-17-2010, 05:31 PM

Quote:

Originally Posted by kyle_saville

thanks guys but i resoldered the pots and still didnt fix the problem so i figure it has to be a bad pot. i removed the solder and took out the master low pot, does anyone know a good site to order a replacement for it???

Digikey

kyle_saville · #14 07-17-2010, 07:47 PM

thanks dude, can you tell me exactly what kind to get, i know that is 50k ohms and i need it split shaft and pcb. but i can't really find it on digikey

**B-string** · #15 07-17-2010, 10:06 PM

Original was a Noble pot 50K as you already know, "B" taper 1 watt, newest are 7mm shaft early were 9mm shaft.

kyle_saville · #16 07-17-2010, 11:36 PM

I feel really dumb, but i'm still having trouble finding a replacement pot online. If someone could give me a link to a replacement one it would help me ALOT. thanks

kyle_saville · #17 07-18-2010, 02:42 PM

would this pot work? i believe everything is right except it doesn't say the wattage
http://www.mojotone.com/amp-parts/16...-Potentiometer

kyle_saville · #18 07-21-2010, 03:21 PM

anyone?

Pandafist · #19 07-21-2010, 03:27 PM

My main amp is the 800RB
Sorry to inform you, but you MIGHT need a cap replacement job done.
I can't explain why taking the nut off the jack helped, but it bad caps would DEFINITELY explain the rest of the symptoms.
I had mine recapped and it was a whole new world of awesomeness when I got it back.

kyle_saville · #20 07-29-2010, 08:49 PM

ok guys, i pretty much am positive its a bad pot, but i am still having trouble finding one, the only 2 websites i found with exact replacements are oaktreevintage which are $25 and ampcrazy which has a $25 limit and the pots are $10. Can anyone point me to a website that has exactly what i need?