carpenter
Full Member level 6
Hello ,
I repair or more precise restoring old HP Electronics Load , I have service manual with list of parts and full schematics.
And have problem.
See on picture, for example R173+R173+D34 they are in bold black frame.
These components are not listed in the parts list and on schematics are in bold black frame.
My question is why?
Were they added to the device additionally or were they removed as unnecessary?
I don't know why they are there
CV Prog is 0 +10V voltge by which set voltge on the load
VMON* is really voltage on the load 0 -10V this two voltage is summing on precise 0,1% resistor R105 , R117 and amplifier U13 LF412 drive big power MOSFET in the load so that VMON* =CV Prog. Simple and clear, I do not understand the meaning of D34 etc.
UNREG is voltage on gate first power MOSFET in the load (negative +6.5V for from close and full open MOSFET) , may be R171=91k and R173=9.1k but who knows, it doesn't make much sense to me.
I repair or more precise restoring old HP Electronics Load , I have service manual with list of parts and full schematics.
And have problem.
See on picture, for example R173+R173+D34 they are in bold black frame.
These components are not listed in the parts list and on schematics are in bold black frame.
My question is why?
Were they added to the device additionally or were they removed as unnecessary?
I don't know why they are there
CV Prog is 0 +10V voltge by which set voltge on the load
VMON* is really voltage on the load 0 -10V this two voltage is summing on precise 0,1% resistor R105 , R117 and amplifier U13 LF412 drive big power MOSFET in the load so that VMON* =CV Prog. Simple and clear, I do not understand the meaning of D34 etc.
UNREG is voltage on gate first power MOSFET in the load (negative +6.5V for from close and full open MOSFET) , may be R171=91k and R173=9.1k but who knows, it doesn't make much sense to me.