| Products > Test Equipment |
| Keithley 2400 SourceMeter review and teardown |
| << < (16/24) > >> |
| openloop:
--- Quote ---U660 AD7849 is hot and not changing the current setting. --- End quote --- U660 is voltage (not current) control. Although fried DAC would explain observables nicely. |
| kawal:
Yes U660 is removed and the situation is not changed apart from NVdac showing +12V everything else looks the same :palm: TP213 was -0.75V Getting expensive Either way why is there -240V on the output when teh output is not enbaled. |
| openloop:
--- Quote ---U660 is removed --- End quote --- Don't rush into things. :) TP213 (THE control) can be driven down either by voltage drive: TP205 near U211 (not TP206!) OR by current drive: TP207 (near U213) Please check those voltages. (to figure out is it current control that screws things up or is it voltage control) |
| kawal:
TP205 = 0.566V TP207 = -7.4V Openloop Do you have a schematic of this unit ? |
| openloop:
--- Quote ---Do you have a schematic of this unit ? --- End quote --- Nope, just bad experience. ;D --- Quote ---TP207 = -7.4V --- End quote --- So the current control is bad... Let's check the summing point where feedback is added to (current) DAC's output: R238 pin 1: DAC R238 pin 2: DAC + feedback R238 pin 3: feedback What are the voltages on those pins? |
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