Hi All,
[I just tried to post this and it didnt work, so apologies if there is a double somewhere].
Ive had a Mudbunny 2011 PCB sitting around semi populated for a while now and just decided to finish it off for a friends Bday.
Problem is i cant get any sound. The pots scratch and and the volume pot will scratch until you turn it down when it will kill all noise - so i can assume that is working..??
It is all to Green Russian Specs except:
C10= 3n3
C2= 330pf
2n5088 Voltages [ive double checked all the transistors, replaced them all and tried again, etc]
Q1
e-0.137
b-0.73
c-4.5
Q2
e-1.07
b-1.528
c-8.76
Q3
e-0.94
b-1.35
c-8.12
Q4
e-0.88
b-1.48
c-4.9
Ive just reflowed all the solder joint, so i can be relatively sure it isnt that.
I've also traced the PCB using a probe and found signal until the far side of C7. I have also replaced C7 to make sure it isnt that.
Im really running out of ideas here - if anyone had any ideas that would be amazing.
Thanks in advance!!
steve
check the pads of C7, one of them it might sorting with the ground or R18 from solder blobs or bad etching. take a closer look with a magnifying glass if possible or with DMM continuity check.
Is it the etched one? The etch 2011 mudbunny layout is for a different transistor pinout, if it is (or if its the same but fabbed) the 5088 need to be flipped 180degrees. I did this myself on the first one I built!
George
Quote from: hammerheadmusicman on August 02, 2013, 01:14:00 PMthe 5088 need to be flipped 180degrees
Being flipped would give pretty much exactly those voltage readings. I think this is it.
The scratchy pots, though -- especially the volume pot -- have me worried that there is DC across them. There could be other issues.
Hey, I must be learning!