Hi, I stumbled acros this amp and I like to understand it.
I do not have it on the nbench any more so I can't give more details as given now.
It's a commercial design and I do not wish to disclose the manufacturer.
Here is a link:
http://docs.google.com/Present?docid=ddmq8v3q_8cdhv7fcr&invite=4dc5vw
But if you like mail me and I send you a good copy in pdf format.
1. If you look at the PSU, Where is the ground?
Are Q12 and Q15 setup to create a virtual ground?
2. Q14 and Q17 must be the power stage and Q5, Q18 the drivers.
At the moment I received the amp.
PSU part:
fuse F2 was gone.
R26, R73 of the -15V burned.
AMP part:
R16, 17 and Q5 gone.
After replacing this is what I noticed:
D16 is not lit (LED is OK)
+15V is present at R44. +1.8 over D16.
+20.9V at J1 with no load connected.
0V with load.
Why is D16 not ON?
Voltage to low but why?
I checked the parts around D16 and they are all OK.
All other power supp;y voltages measured normal.
What else can be said about this design.
I do not have it on the nbench any more so I can't give more details as given now.
It's a commercial design and I do not wish to disclose the manufacturer.
Here is a link:
http://docs.google.com/Present?docid=ddmq8v3q_8cdhv7fcr&invite=4dc5vw
But if you like mail me and I send you a good copy in pdf format.
1. If you look at the PSU, Where is the ground?
Are Q12 and Q15 setup to create a virtual ground?
2. Q14 and Q17 must be the power stage and Q5, Q18 the drivers.
At the moment I received the amp.
PSU part:
fuse F2 was gone.
R26, R73 of the -15V burned.
AMP part:
R16, 17 and Q5 gone.
After replacing this is what I noticed:
D16 is not lit (LED is OK)
+15V is present at R44. +1.8 over D16.
+20.9V at J1 with no load connected.
0V with load.
Why is D16 not ON?
Voltage to low but why?
I checked the parts around D16 and they are all OK.
All other power supp;y voltages measured normal.
What else can be said about this design.