Bug #275

K2 - Error 402.1 - Frequency switch

Added by tin about 7 years ago. Updated over 4 years ago.

Status:ClosedStart date:19/07/2012
Priority:NormalDue date:
Assignee:tin% Done:

0%

Category:-
Target version:Keithley 2001 #2

Description

Cannot measure 0.032V ±0.005V at A/D IN.

OUT B of the DAC (U531) is set up to output 4.33V at PRECOMP+ (U528 pin 1). The operation of the frequency switch, U522 (FREQ pulled low), is verified by dividing the PRECOMP+ voltage by the voltage ratio across R560 and R558. The “on” resistance (approximately 25Ω) of the analog switch (U522) is added to the resistance of R558 since it is part of the ratio. Again, as in the 400 series tests, this voltage is routed to the A/D buffer (U322) which is configured for x1 gain. Measure 32mV at A/D IN.

suspected components:

U322 - x1 gain
U531
U528
U522
R560
R558

History

#1 Updated by tin over 4 years ago

  • Status changed from New to Resolved

#2 Updated by tin over 4 years ago

  • Status changed from Resolved to Closed

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