This manual contains information relating to the installation, operation, performance testing, calibration, and service of the HP A Multimeter. The information. The HP A has seven functions with 3% to 6% digits of resolu- tion, extendable to 7% .. (). Opt Extra Operating and Service Manual. +$ Hp A Pdf User Manuals. View online or download Hp A Operating Instructions Manual, Service Manual.
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DIY voltage-current curve plot detector.
Connection should not break if you just apply some force to the cable, big enough to lift the meter edge from the table. Reference voltage source is same module from A, using LM ovenized buried zener circuit. Suspects are listed below:.
A Digital Multimeter [Obsolete] | Keysight (formerly Agilent’s Electronic Measurement)
Dc Volts Linearity Calibration Dc Current Majual Calibration hp3457q Actual amplifier part is Q, and Q help for constant voltage between source and drain of Q HP A input frontend and signal conditioning schematics Image Vos adjustment trimmer access port in shield cover.
Dc Voltage Function COTO relay for front end. Changing The Security Code Linear power regulator and optoisolation interface between the domains Outguard earth-referenced domain contains of: Inguard shield removed, revealed AC and front end main board.
Calibration coefficients are stored in SRAMwhich is powered even if instruments powered off, with help of on-board lithium battery. This allows to experiment easy without risk of damaging the board taking everything apart for each component swap.
Dc Volts Gain Calibration Wiring Block Preparation Inner protection shields Image 7: Input amplifier after my modifications. Performance Tests cont’d HP A rear view on modified screen Result at night. Front Panel Inputs Measurement noise data plots Manial practical notes about modifications After Q replacement the complete input hpp3457a balance had to be adjusted and re-calibrated.
Preparation For Use Now turn the meter again, front panel facing to us, remove top plastic cover and under it we can find top shield, holder of the multiplexer board. R6 and R14 up3457a their protection diodes prevent gates from excessive current. Ac Voltage Performance Tests This means that disassembly and cover removals not required for adjustment and calibration with few exceptions, covered later.
Second, similar adjustment procedure should be performed in diagnostics mode 2, to correct AC frequency flatness for input divider. For 30 V and V additional As result there is no mechanical switch on front panel to change terminal side manually.
HP A OPERATING INSTRUCTIONS MANUAL Pdf Download.
This is little tricky. Experimentally, I figured out that there is indeed balance offset. Replacement Q matching One kind person my kind regards presented me with thin copper foil with adhesive layer. Note that A conversion from ADC is actually 7 digits, but least digit is averaged out and not reported to the front-end, nor the Manyal port remote controller.
HP 3457A Operating Instructions Manual
manyal After Q replacement with faster curve than original and U more gain input amplifier circuitry started to oscillate with frequency around kHz. Note, that on low voltage ranges 0. Grounding wire terminal Carefully lift rear side of the shield, disconnect cable from rear terminal and turn screen up. Rear Terminal Offset Test Hmm, hold on a moment? Ac Convertor Frequency Response Adjustment This was required to enable trimpot RP1 setting for both negative and positive gate voltage.
Replacement foil resistors S After Q replacement with faster curve than original and U more gain input amplifier circuitry started hp345a oscillate with frequency around kHz. Much more important fact is, that display is now visible and usable at night time.