Select autorange or manual ranging. Menu Command Keys. • Immediate access to eight common commands. • Shifted keys allow simple access to complete. No other specifications are affected. Refer to the HP A Operating, Programming, and. Configuration Manual for complete performance specifications;. Hp A Pdf User Manuals. View online or download Hp A Repair Manual , Technical Manual.

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Hewlett-Packard was a big name in 20th century for electronics and test equipment. They designed and manufactured many equipment which works and not too shady even by modern standards today, 25 years after. Today electronics test instrumentation part become further split and is known by brand Keysight Technologies.

For those who are not familiar with A, some very useful operation details and features are covered in this HP Journaldedicated for A release. Journal sourced from HP Labs journal archive. But today we will look on old unit, still wearing HP logo, manufactured somewhat in But think for a second, metrology-grade instrumentation market is very conservative.

Agilent / HP A Front Panel Manual |

So one may consider this project as deposit investment, given that instrument can be repaired and brought back to full specifications. It does take tremendous amount of time and effort to test, validate and prove stability and performance of such machines, where no detail is insignificant. Old, but not obsolete. Hope this giving you idea how much it can go as hp345a8, even for broken meter with unknown condition, and why is it so. This means we will not be doing expensive boards swap unless absolutely unavoidable.

If you asking yourself about this, then you are not ready for it. Paid cost for such a unit WITH proper repair can easily exceed cost of buying a fully tested unit.

Also old units manufactured mqnual thanwould have Dallas NVRAM batteries already near end of life, with risk of losing calibration data any day.

Meters containing Option will return a 1,0 when queried with an OPT? Redistribution and use of this article or any images or files referenced in it, in source and binary forms, with or without modification, are permitted provided that the following conditions are met:. All information posted here is hosted just for education purposes and provided AS IS. In no event shall the author, xDevs. Hp458a A front and rear faces.

HP A top and bottom sides, without covers. Unit covers are very dirty overall, with lots of rust on rear part of steel chassis. That would be a major disaster for repair, if such happen.

HP A side handle and rear panel. All sensitive analog boards are enclosed in separate insulated aluminum cage, held by hp3458s standoffs. HP A internals with inguard shields. A1 DC board overview. Pay attention to mains voltage selection switches, located near mains IEC connector.

Using incorrect voltage setting e. This is likely what happened to my unit by previous owner, and was a root cause of damage. Keysight A Multimeter datasheet. Quick Reference Guide, Edition 2, Dec If your unit is old, worth to check if any of them required to do.


The original A fan filter is no longer available. The replacement fan filter uses three unique parts. The replacement kit consists of two unique parts and an installation note. As usual, we have project tracker, dedicated for A repair so any one can contribute, or track the progress. Before starting any repair, good idea to read thru repair hp358a, to get idea of board functions and purpose.

3458A Digital Multimeter, 8 ½ Digit

HP has both assembly and component level repair manuals, which include full schematics and board assembly drawings. I still remember repair efforts and countless hours without schematics, deciphering circuitry in Keithley DMM.

Some parts are available for order from Keysight. List of parts and cost from Keysight, Excel table. As expected, most mechanical parts are affordable to allow minor repair, but when we start looking at PCBA level repair cost is quickly jumps to thousands of dollars, making whole project worthless.

Except missing A9 DCV reference board, everything is there, no missing parts on boards. Vacuum-fluorescent display glass is not damaged barium flash on glass from getter is shiny dark, if air leak into tube it would become white. Before doing any repairs or applying power, wise to check physical condition of components and boards inside instrument. Often this easy operation can spot obvious failures, such as blown MOSFET s, burnt resistors or missing parts, saving time for further repair.

If you see leaked electrolyte or bulging capacitors, do not apply power.

Replace broken parts and clean board thoroughly, to avoid further damage. If any visible discoloration found, use DMM to check connection resistances, and rewire broken nets, mabual needed. I usually replace old electrolytic aluminum capacitors to fresh ones even if they look okay. It does not cost much, but will save the question regarding if original ones are good or bad, or at borderline.

Condition of PCBA s. Front panel must be removed in amnual to remove mains transformer. To do so, lift right side of panel and release it from chassis frame. Be careful with front panel assembly, as vacuum display glass is fragile.

HP 3458A Manuals

Front panel board and keypad. Front panel PCB label. A6 power supply PCBAtop and bottom side. After installing fuse, meter digital section can now power on, giving short beep and displaying error message on VFD. Main power convertor is based around switching ST Lwhich is capable of supplying up to 4 amps of current. This controller handles buttons, buzzer and display operations.

NE nearby provides tone signal to buzzer. Regulator on PCBheatsink removed. Black 2-pin connector at left of regulator is fan header. Gunk in fan motor and motor board.

My favorite destructive analysis reveals fan support with dual ball-bearings. Lubricant was long gone, resulting metal-type dirt and specs in motor. I also ordered some capacitors from DigiKey to replace all electrolytes on this board. You can call me paranoid and insane, but I would not trust 20 year old electrolyte capacitors, even if they are mnaual by 1st tier manufacturers. No, better be safe than sorry… Take them out, and say thank you later.


Leaking capacitors from A6 board. Electrolyte got already out and started its destruction activities. Cleaning PCB required due electrolyte corrosion and solder mask damage. Now I am really glad that we did not cut corners here, and removed them. I was wondering and measured old caps too, for series capacitance and resistance, with help of repaired HP B.

Capacitor measurements with HP B. HP digital outguard PCBtop and bottom view. Meter digital brain, firmware, calibration ROM and digital interface circuits are located on this dual-layer board. We have older board version with all thru hole components, while newer meters usually have smaller SMT -type A5 controller. If your meter still contains valid calibration data, there is a way to read calibration constants back, hp358a that meter can power up and enter operation mode.

For latest version of A5 PCBother electronics video blogger, Martin Lorton also contributed some nice hi-resolution photos of his newer A5 board, so we can check details up3458a parts on it:. Board is redesign to reuse modern components but fully compatible firmware-wise. Firmware ROM Rev.

He also have nice video covering his A here on YouTube channel. Be sure to check it out. There is Service note AA covering this upgrade. Instead of soldering new chips in place, I opted to solder good quality gold-plated collet sockets, so in future soldering would not manaul required. After meter repair and calibration, data stored in that chip will be critical. This makes it rather manuao, as in 24 years resistors and parts in meter drifted more than such old data could be used, as original DC reference board is missing.

But since we have nothing better, I will copy this data into new Dallas DS so we can use it as starting point. Of course, that is due we have nothing else connected, and processor expects data from analog side.

My board also fall within range of Service note A: There is interesting open connection routing with open mask on top side of PCBjust near connector pins. I also replaced GPIB connector, as original one is really rusty.

Timelapse video of HP A restoration in progress. Inguard power supply board, top and bottom view. Broken transformer, disassembly attempt. Each winding have its own metal inner shield to reduce leakage and coupling between different transformer sections.