HELP!!! GK Backline 600 problem

[B-string]

I was asking about the Boost since it is pre effect send.

I have also seen single pedals in a chain have issues and drag the entire loop down.

Seems more like corrosion though since you have trouble with the tuner jack as well.

Hope it's an easy fix.

Actually the Boost is post effects return. It is that way on all G-K amps.

 

[jHawk Customs]

My bad- I said it backwards-
The loop is pre Boost is what I meant to say- thanks for catching that.

 

[B-string]

No trouble

 

[tdshea]

I just went from a SVT Pro 7 brought it back , to a Little Mark tube 800 , brought it back , now I just picked up rb 1001 GK , I love the headroom , and punch ! I think I'm done with the little fake digital watts . The heads powering an Avatar B212 4 ohm 1000 watt cab and my bass is 1982 G&L L 2000 E . Let's see how this works out !

 

[Donny_Pbass]

I just repaired on of these with similar problems. It was popping and cracking with normal channel volume up past 3. Theres a separate TL072 driver after Eff loop, check signal to eliminate from the equation. Traced my problem back to bad transistor on preamp and (1) bad OpAmp chip. This has a slew of TL072's, modifying the tone in a series chain. I replaced U-9A (also replaced u-1, u-5, ) and Q3 (J113) FET. Its intricate work, so have a tech isolate which one is bad and de-solder off the board. I found a high level of corrosion on PCB (capacitors off gassing) and a bunch of filthy pots. Not a robust design (never see this crap with Peaveys) but heres a schematic, (mine is Rev B) good luck > Invalid Link Removed