Hello everyone! Noob here. Glad to have found this forum. I hope I can get some advice on repairing an older stereo amplifier I have.
It's an Electron Kinetics Eagle 2C amp from the early 90's. It was assembled and inspected around mid December, 1992. One channel has gone out. I tried contacting the company through email, and also called, but have yet to get an answer! This has been a couple of weeks now. I have also tried searching for a schematic for this amp, but no luck!
So, here is what I have done so far. I have checked the main power fuse, and the 2 fuses on the pcb, and they are all good. I then measured the voltage for all of the transistors. These are measurements I got from the top row starting from left to right. I have also included some photos. The first photo shows what appears to be some brown stuff on one of the caps. Not sure if it is from leakage or some kind of glue? The second photo show the channel A side of the amp, and the last photo shows channel B.
(CHANNEL A) Starting from Top left (second photo)
#1 Sanken 2SC2774 transistor B=.631 DCV/ C=48.0 DCV/ E=.018 DCV
#2 Sanken C2168 transistor B=1.22 DCV/ C=47.7 DCV/ E=.627 DCV
#3 Sanken 2SC2774 transistor B=.626 DCV/ C=48.0 DCV/ E=.017 DCV
#4 Sanken A958 transistor B=46.4 DCV/ C=1.22 DCV/ E=47.3 DCV
(CHANNEL B) Starting from Top left (third photo)
#5 Sanken A958 transistor B=47.8 DCV/ C= -40.0 DCV and appeared to be dropping?/ E=46.1 DCV
#6 Sanken 2SC2774 transistor B= -21.0 DCV and dropping in voltage/ C= 46.8 DCV/ E= -19.6 DCV
#7 Sanken C2168 transistor B= -18.8 DCV/ C=46.8 DCV/ E= -18.9 DCV
#8 Sanken 2SC2774 transistor B= -18.75 DCV/ C=46.9 DCV/ E= -19.4 DCV
Here are the rest of the transistors located on the bottom. The measurements are:
Channel (A) Starting at bottom left (second photo)
#1(2SA1170) B= .603 DCV/ C= -46.55 DCV/ E= -.012 DCV
#2(A958) B= -1.22 DCV/ C= -46.33 DCV/ E= -.600 DCV
#3(2SA1170) B= -.593 DCV/ C= -47.3 DCV/ E= -.002 DCV
#4(2SC2168 ???) B= -44.7 DCV/ C= -1.20 DCV/ E= -44.8 DCV
(CHANNEL B) Starting from bottom left (third photo)
#5(2SC2168???) B= -44.8 DCV/ C= -2.27 DCV/ E= -44.8 DCV
#6(2SA1170) B= -1.15 DCV/ C= -45.9 DCV/ E= -.63 DCV
#7(A958) B= -1.9 DCV/ C= -46.7 DCV/ E= -1.22 DCV
#8(2SA1170) B= -1.42 DCV/ C= -46.1 DCV/ E= -.75 DCV
I also measured the speaker outputs, and got these measurements with my Fluke DMM:
Channel (A)= .001 DCV
Channel (B)= -21.8 DCV and then starts to drop in voltage.
The measurements for the OP-AMPS:
OP-AMP (#1) Pin #1= -14.76 DCV/ Pin #2= -.025 DCV/ Pin #3= 15.27 DCV/ Pin #4= .002 DCV Perhaps there was no voltage on this pin #4?
Pin #5= 14.80 DCV/ Both Pins #6 & #7 measured no voltage/ Pin #8= -14.76 DCV
OP-AMP (#2) Pin #1= -14.73 DCV/ Pin #2= -.633 DCV/ Pin #3= -.677 DCV/ Pin #4= -14.8 DCV/ Pin #5= -11.50 DCV/ Pin #6= 15.28 DCV/ Pin #7= -.004 DCV/ Pin #8= -14.75 DCV
Could someone help me figure out what may be causing one side not to work? Would be very grateful!
Thanks in advanced!
Mario P.
It's an Electron Kinetics Eagle 2C amp from the early 90's. It was assembled and inspected around mid December, 1992. One channel has gone out. I tried contacting the company through email, and also called, but have yet to get an answer! This has been a couple of weeks now. I have also tried searching for a schematic for this amp, but no luck!
So, here is what I have done so far. I have checked the main power fuse, and the 2 fuses on the pcb, and they are all good. I then measured the voltage for all of the transistors. These are measurements I got from the top row starting from left to right. I have also included some photos. The first photo shows what appears to be some brown stuff on one of the caps. Not sure if it is from leakage or some kind of glue? The second photo show the channel A side of the amp, and the last photo shows channel B.
(CHANNEL A) Starting from Top left (second photo)
#1 Sanken 2SC2774 transistor B=.631 DCV/ C=48.0 DCV/ E=.018 DCV
#2 Sanken C2168 transistor B=1.22 DCV/ C=47.7 DCV/ E=.627 DCV
#3 Sanken 2SC2774 transistor B=.626 DCV/ C=48.0 DCV/ E=.017 DCV
#4 Sanken A958 transistor B=46.4 DCV/ C=1.22 DCV/ E=47.3 DCV
(CHANNEL B) Starting from Top left (third photo)
#5 Sanken A958 transistor B=47.8 DCV/ C= -40.0 DCV and appeared to be dropping?/ E=46.1 DCV
#6 Sanken 2SC2774 transistor B= -21.0 DCV and dropping in voltage/ C= 46.8 DCV/ E= -19.6 DCV
#7 Sanken C2168 transistor B= -18.8 DCV/ C=46.8 DCV/ E= -18.9 DCV
#8 Sanken 2SC2774 transistor B= -18.75 DCV/ C=46.9 DCV/ E= -19.4 DCV
Here are the rest of the transistors located on the bottom. The measurements are:
Channel (A) Starting at bottom left (second photo)
#1(2SA1170) B= .603 DCV/ C= -46.55 DCV/ E= -.012 DCV
#2(A958) B= -1.22 DCV/ C= -46.33 DCV/ E= -.600 DCV
#3(2SA1170) B= -.593 DCV/ C= -47.3 DCV/ E= -.002 DCV
#4(2SC2168 ???) B= -44.7 DCV/ C= -1.20 DCV/ E= -44.8 DCV
(CHANNEL B) Starting from bottom left (third photo)
#5(2SC2168???) B= -44.8 DCV/ C= -2.27 DCV/ E= -44.8 DCV
#6(2SA1170) B= -1.15 DCV/ C= -45.9 DCV/ E= -.63 DCV
#7(A958) B= -1.9 DCV/ C= -46.7 DCV/ E= -1.22 DCV
#8(2SA1170) B= -1.42 DCV/ C= -46.1 DCV/ E= -.75 DCV
I also measured the speaker outputs, and got these measurements with my Fluke DMM:
Channel (A)= .001 DCV
Channel (B)= -21.8 DCV and then starts to drop in voltage.
The measurements for the OP-AMPS:
OP-AMP (#1) Pin #1= -14.76 DCV/ Pin #2= -.025 DCV/ Pin #3= 15.27 DCV/ Pin #4= .002 DCV Perhaps there was no voltage on this pin #4?
Pin #5= 14.80 DCV/ Both Pins #6 & #7 measured no voltage/ Pin #8= -14.76 DCV
OP-AMP (#2) Pin #1= -14.73 DCV/ Pin #2= -.633 DCV/ Pin #3= -.677 DCV/ Pin #4= -14.8 DCV/ Pin #5= -11.50 DCV/ Pin #6= 15.28 DCV/ Pin #7= -.004 DCV/ Pin #8= -14.75 DCV
Could someone help me figure out what may be causing one side not to work? Would be very grateful!
Thanks in advanced!
Mario P.
Attachments
-
210.7 KB Views: 19
-
279.3 KB Views: 22
-
263 KB Views: 20