input bias servo with OP177FPZ

[fantast]

heaveno,

I have some OP 177FPZ in spare. Was it possible to use them for the input bias servo OPs without any changes?

Kind regards
Claus

[peranders]

It should work.

[fantast]

Thanks Anders,

I assume I shall remove C61/62 and G61/62 if I am going to use them in the input bias servo?

(And possibly I will also do not need the Zeners DZ9 and DZ10).

Many regards
Claus

[peranders]

Correct and the zeners will go also.

[fantast]

What about the tendency to put DC back into the MC System in your design?

[peranders]

The input servo avoids this.

[fantast]

Maybe a silly question, but how was it necessary to have a 8slot wago for power supply, as only 5 channels seem to be sufficient (R+/R-/L+/L-/Ground)?
Kind regards
Claus

PS: Finsished with the soldering now and putting the power supply to it...

[peranders]

You can have one or two power supplies.

[fantast]

Thanks,

now the hard stuff. It is running, however I am missing the left preamp part (no diode, no output). Any good idea where to start to find the failure?

Best regards
Claus

[peranders]

What is your problem? I'm not sure what you mean.

[fantast]

I have checked all connections and parts and everything seams to be OK so far. However, I have a big unbalance at the crossing going to R16 and to R17. Via R8 and T2 the the voltage in around 6V wheras it is just 0.6V the way across R9 and T1. I am not sure where this is from.
Also the DC adjust (after R29) is constantly increasing, starting 5.2V going up to 8V within in few minutes.

Kind regards
Claus

[fantast]

OK.
It was the Zener DZ1 :roll:
Regards
Claus

[fantast]

It is running. First impression is quite good  :wink:
Thanks Anders

[peranders]

Good news!

[fantast]

Next time I am at Chalmers or VTI I will give you a call.
Cheers,
Claus